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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Mobile Ad hoc Networking (MANET) T. Clausen 3 Internet-Draft LIX, Ecole Polytechnique, France 4 Intended status: Standards Track C. Dearlove 5 Expires: January 11, 2009 BAE Systems Advanced Technology 6 Centre 7 P. Jacquet 8 Project Hipercom, INRIA 9 The OLSRv2 Design Team 10 MANET Working Group 11 July 10, 2008 13 The Optimized Link State Routing Protocol version 2 14 draft-ietf-manet-olsrv2-07 16 Status of This Memo 18 By submitting this Internet-Draft, each author represents that any 19 applicable patent or other IPR claims of which he or she is aware 20 have been or will be disclosed, and any of which he or she becomes 21 aware will be disclosed, in accordance with Section 6 of BCP 79. 23 Internet-Drafts are working documents of the Internet Engineering 24 Task Force (IETF), its areas, and its working groups. Note that 25 other groups may also distribute working documents as Internet- 26 Drafts. 28 Internet-Drafts are draft documents valid for a maximum of six months 29 and may be updated, replaced, or obsoleted by other documents at any 30 time. It is inappropriate to use Internet-Drafts as reference 31 material or to cite them other than as "work in progress." 33 The list of current Internet-Drafts can be accessed at 34 http://www.ietf.org/ietf/1id-abstracts.txt. 36 The list of Internet-Draft Shadow Directories can be accessed at 37 http://www.ietf.org/shadow.html. 39 This Internet-Draft will expire on January 11, 2009. 41 Abstract 43 This document describes version 2 of the Optimized Link State Routing 44 (OLSRv2) protocol. The protocol embodies an optimization of the 45 classical link state algorithm tailored to the requirements of a 46 Mobile Ad hoc NETwork (MANET). 48 The key optimization in OLSRv2 is that of multipoint relays (MPRs), 49 providing an efficient mechanism for network-wide broadcast of link 50 state information (i.e. reducing the cost of performing a network- 51 wide link state broadcast). A secondary optimization is that OLSRv2 52 employs partial link state information; each node maintains 53 information about all destinations, but only a subset of links. 54 Consequently, only selected nodes flood link state advertisements 55 (thus reducing the number of network-wide link state broadcasts) and 56 these advertisements contain only a subset of links (thus reducing 57 the size of network-wide link state broadcasts). The partial link 58 state information thus obtained still allows each OLSRv2 node to at 59 all times maintain optimal (in terms of number of hops) routes to all 60 destinations in the network. 62 OLSRv2 imposes minimum requirements on the network by not requiring 63 sequenced or reliable transmission of control traffic. Furthermore, 64 the only interaction between OLSRv2 and the IP stack is routing table 65 management. 67 OLSRv2 is particularly suitable for large and dense networks as the 68 technique of MPRs works best in this context. 70 Table of Contents 72 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 73 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 74 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 8 75 4. Protocol Overview and Functioning . . . . . . . . . . . . . . 10 76 5. Protocol Parameters and Constants . . . . . . . . . . . . . . 13 77 5.1. Local History Times . . . . . . . . . . . . . . . . . . . 13 78 5.2. Message Intervals . . . . . . . . . . . . . . . . . . . . 14 79 5.3. Advertised Information Validity Times . . . . . . . . . . 14 80 5.4. Received Message Validity Times . . . . . . . . . . . . . 15 81 5.5. Jitter . . . . . . . . . . . . . . . . . . . . . . . . . . 16 82 5.6. Hop Limit Parameter . . . . . . . . . . . . . . . . . . . 16 83 5.7. Willingness . . . . . . . . . . . . . . . . . . . . . . . 17 84 5.8. Parameter Change Constraints . . . . . . . . . . . . . . . 17 85 6. Information Bases . . . . . . . . . . . . . . . . . . . . . . 19 86 6.1. Local Information Base . . . . . . . . . . . . . . . . . . 19 87 6.1.1. Originator Set . . . . . . . . . . . . . . . . . . . . 19 88 6.1.2. Local Attached Network Set . . . . . . . . . . . . . . 20 90 6.2. Node Information Base . . . . . . . . . . . . . . . . . . 20 91 6.3. Topology Information Base . . . . . . . . . . . . . . . . 21 92 6.3.1. Advertised Neighbor Set . . . . . . . . . . . . . . . 21 93 6.3.2. Advertising Remote Node Set . . . . . . . . . . . . . 21 94 6.3.3. Topology Set . . . . . . . . . . . . . . . . . . . . . 22 95 6.3.4. Attached Network Set . . . . . . . . . . . . . . . . . 22 96 6.3.5. Routing Set . . . . . . . . . . . . . . . . . . . . . 23 97 6.4. Processing and Forwarding Information Base . . . . . . . . 23 98 6.4.1. Received Set . . . . . . . . . . . . . . . . . . . . . 24 99 6.4.2. Processed Set . . . . . . . . . . . . . . . . . . . . 24 100 6.4.3. Forwarded Set . . . . . . . . . . . . . . . . . . . . 24 101 6.4.4. Relay Set . . . . . . . . . . . . . . . . . . . . . . 25 102 7. Packet Processing and Message Forwarding . . . . . . . . . . . 26 103 7.1. Actions when Receiving an OLSRv2 Packet . . . . . . . . . 26 104 7.2. Actions when Receiving an OLSRv2 Message . . . . . . . . . 26 105 7.3. Message Considered for Processing . . . . . . . . . . . . 27 106 7.4. Message Considered for Forwarding . . . . . . . . . . . . 28 107 8. Packets and Messages . . . . . . . . . . . . . . . . . . . . . 31 108 8.1. HELLO Messages . . . . . . . . . . . . . . . . . . . . . . 31 109 8.1.1. HELLO Message TLVs . . . . . . . . . . . . . . . . . . 32 110 8.1.2. HELLO Message Address Block TLVs . . . . . . . . . . . 32 111 8.2. TC Messages . . . . . . . . . . . . . . . . . . . . . . . 32 112 8.2.1. TC Message TLVs . . . . . . . . . . . . . . . . . . . 33 113 8.2.2. TC Message Address Block TLVs . . . . . . . . . . . . 34 114 9. HELLO Message Generation . . . . . . . . . . . . . . . . . . . 35 115 9.1. HELLO Message: Transmission . . . . . . . . . . . . . . . 35 116 10. HELLO Message Processing . . . . . . . . . . . . . . . . . . . 36 117 10.1. Updating Willingness . . . . . . . . . . . . . . . . . . . 36 118 10.2. Updating MPR Selectors . . . . . . . . . . . . . . . . . . 36 119 10.3. Symmetric 1-Hop and 2-Hop Neighborhood Changes . . . . . . 36 120 11. TC Message Generation . . . . . . . . . . . . . . . . . . . . 38 121 11.1. TC Message: Transmission . . . . . . . . . . . . . . . . . 39 122 12. TC Message Processing . . . . . . . . . . . . . . . . . . . . 40 123 12.1. Initial TC Message Processing . . . . . . . . . . . . . . 40 124 12.1.1. Populating the Advertising Remote Node Set . . . . . . 41 125 12.1.2. Populating the Topology Set . . . . . . . . . . . . . 42 126 12.1.3. Populating the Attached Network Set . . . . . . . . . 42 127 12.2. Completing TC Message Processing . . . . . . . . . . . . . 43 128 12.2.1. Purging the Topology Set . . . . . . . . . . . . . . . 43 129 12.2.2. Purging the Attached Network Set . . . . . . . . . . . 43 130 13. Information Base Changes . . . . . . . . . . . . . . . . . . . 44 131 14. Selecting MPRs . . . . . . . . . . . . . . . . . . . . . . . . 45 132 15. Populating Derived Sets . . . . . . . . . . . . . . . . . . . 47 133 15.1. Populating the Relay Set . . . . . . . . . . . . . . . . . 47 134 15.2. Populating the Advertised Neighbor Set . . . . . . . . . . 47 135 16. Routing Set Calculation . . . . . . . . . . . . . . . . . . . 48 136 16.1. Network Topology Graph . . . . . . . . . . . . . . . . . . 48 137 16.2. Populating the Routing Set . . . . . . . . . . . . . . . . 49 138 16.3. Routing Set Updates . . . . . . . . . . . . . . . . . . . 50 139 17. Proposed Values for Parameters and Constants . . . . . . . . . 51 140 17.1. Local History Time Parameters . . . . . . . . . . . . . . 51 141 17.2. Message Interval Parameters . . . . . . . . . . . . . . . 51 142 17.3. Advertised Information Validity Time Parameters . . . . . 51 143 17.4. Received Message Validity Time Parameters . . . . . . . . 51 144 17.5. Jitter Time Parameters . . . . . . . . . . . . . . . . . . 51 145 17.6. Hop Limit Parameter . . . . . . . . . . . . . . . . . . . 51 146 17.7. Willingness Parameter and Constants . . . . . . . . . . . 52 147 18. Sequence Numbers . . . . . . . . . . . . . . . . . . . . . . . 53 148 19. Security Considerations . . . . . . . . . . . . . . . . . . . 54 149 19.1. Confidentiality . . . . . . . . . . . . . . . . . . . . . 54 150 19.2. Integrity . . . . . . . . . . . . . . . . . . . . . . . . 54 151 19.3. Interaction with External Routing Domains . . . . . . . . 55 152 20. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 57 153 20.1. Message Types . . . . . . . . . . . . . . . . . . . . . . 57 154 20.2. Message TLV Types . . . . . . . . . . . . . . . . . . . . 57 155 20.3. Address Block TLV Types . . . . . . . . . . . . . . . . . 58 156 21. References . . . . . . . . . . . . . . . . . . . . . . . . . . 60 157 21.1. Normative References . . . . . . . . . . . . . . . . . . . 60 158 21.2. Informative References . . . . . . . . . . . . . . . . . . 60 159 Appendix A. Node Configuration . . . . . . . . . . . . . . . . . 62 160 Appendix B. Example Algorithm for Calculating MPRs . . . . . . . 63 161 B.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 63 162 B.2. MPR Selection Algorithm for each OLSRv2 Interface . . . . 64 163 Appendix C. Example Algorithm for Calculating the Routing Set . . 65 164 C.1. Add Local Symmetric Links . . . . . . . . . . . . . . . . 65 165 C.2. Add Remote Symmetric Links . . . . . . . . . . . . . . . . 66 166 C.3. Add Attached Networks . . . . . . . . . . . . . . . . . . 67 167 Appendix D. Example Message Layout . . . . . . . . . . . . . . . 68 168 Appendix E. Constraints . . . . . . . . . . . . . . . . . . . . . 70 169 Appendix F. Flow and Congestion Control . . . . . . . . . . . . . 74 170 Appendix G. Contributors . . . . . . . . . . . . . . . . . . . . 75 171 Appendix H. Acknowledgements . . . . . . . . . . . . . . . . . . 76 173 1. Introduction 175 The Optimized Link State Routing protocol version 2 (OLSRv2) is an 176 update to OLSRv1 as published in [RFC3626]. Compared to RFC3626, 177 OLSRv2 retains the same basic mechanisms and algorithms, while 178 providing a more flexible signaling framework and some simplification 179 of the messages being exchanged. Also, OLSRv2 accommodates either 180 IPv4 and IPv6 addresses in a compact manner. 182 OLSRv2 is developed for mobile ad hoc networks. It operates as a 183 table driven, proactive protocol, i.e. it exchanges topology 184 information with other nodes in the network regularly. Each node 185 selects a set of its neighbor nodes as "MultiPoint Relays" (MPRs). 186 Control traffic may be flooded through the network using hop by hop 187 forwarding, but where a node only needs to forward control traffic 188 directly received from its MPR selectors (nodes which have selected 189 it as an MPR). This mechanism, denoted "MPR flooding", provides an 190 efficient mechanism for information distribution within the MANET by 191 reducing the number of transmissions required. 193 Nodes selected as MPRs also have a special responsibility when 194 declaring link state information in the network. A sufficient 195 requirement for OLSRv2 to provide shortest (lowest hop count) path 196 routes to all destinations is that nodes declare link state 197 information for their MPR selectors, if any. Additional available 198 link state information may be transmitted, e.g. for redundancy. 199 Thus, as well as being used to facilitate MPR flooding, use of MPRs 200 allows the reduction of the number and size of link state messages, 201 and MPRs are used as intermediate nodes in multi-hop routes. 203 A node selects MPRs from among its one hop neighbors connected by 204 "symmetric", i.e. bi-directional, links. Therefore, selecting routes 205 through MPRs automatically avoids the problems associated with data 206 packet transfer over uni-directional links (such as the problem of 207 not getting link layer acknowledgments at each hop, for link layers 208 employing this technique). 210 OLSRv2 is developed to work independently from other protocols. 211 (Parts of OLSRv2 have been published separately as [packetbb], 212 [timetlv], [RFC5148] and [nhdp] for wider use.) Likewise, OLSRv2 213 makes no assumptions about the underlying link layer. However, 214 OLSRv2 may use link layer information and notifications when 215 available and applicable, as described in [nhdp]. 217 OLSRv2, as OLSRv1, inherits its concept of forwarding and relaying 218 from HIPERLAN (a MAC layer protocol) which is standardized by ETSI 219 [HIPERLAN], [HIPERLAN2]. 221 2. Terminology 223 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 224 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 225 "OPTIONAL" in this document are to be interpreted as described in 226 [RFC2119]. 228 MANET specific terminology is to be interpreted as described in 229 [packetbb] and [nhdp]. 231 Additionally, this document uses the following terminology: 233 Node - A MANET router which implements the Optimized Link State 234 Routing protocol version 2 as specified in this document. 236 OLSRv2 interface - A MANET interface, running OLSRv2. Note that all 237 references to MANET interfaces in [nhdp] refer to OLSRv2 238 interfaces when using [nhdp] as part of OLSRv2. 240 Address - An address, as recorded in the Information Bases specified 241 by this protocol, and included in HELLO and TC messages generated 242 by this protocol, may be either an address or an address prefix. 243 These can be represented as a single address object in a HELLO or 244 TC message, as defined by [packetbb]. An address so represented 245 is considered to have a prefix length equal to its length (in 246 bits) when considered as an address object, and a similar 247 convention is used in the Information Bases specified by this 248 protocol. Two addresses (address objects) are considered equal 249 only if their prefix lengths are also equal. 251 Willingness - The willingness of a node is a numerical value between 252 WILL_NEVER and WILL_ALWAYS (both inclusive), which represents the 253 node's willingness to be selected as an MPR. 255 Willing symmetric 1-hop neighbor - A symmetric 1-hop neighbor of 256 this node which has willingness not equal to WILL_NEVER. 258 Symmetric strict 2-hop neighbor - A symmetric 2-hop neighbor of this 259 node which is not a symmetric 1-hop neighbor of this node, and is 260 a symmetric 1-hop neighbor of a willing symmetric 1-hop neighbor 261 of this node. 263 Symmetric strict 2-hop neighbor through OLSRv2 interface I - A 264 symmetric strict 2-hop neighbor of this node which is a symmetric 265 1-hop neighbor of a willing symmetric 1-hop neighbor of this node 266 by a symmetric link including OLSRv2 interface I. This node MAY 267 elect to consider only information received over OLSRv2 interface 268 I in making this determination. 270 Symmetric strict 2-hop neighborhood - The set of the symmetric 271 strict 2-hop neighbors of a node. 273 Multipoint relay (MPR) - A node which is selected by its symmetric 274 1-hop neighbor, node X, to "re-transmit" all the broadcast 275 messages that it receives from node X, provided that the message 276 is not a duplicate, and that the hop limit field of the message is 277 greater than one. 279 MPR selector - A node which has selected its symmetric 1-hop 280 neighbor, node X, as one of its MPRs is an MPR selector of node X. 282 MPR flooding - The optimized MANET-wide information distribution 283 mechanism, employed by this protocol, in which a message is 284 relayed by only a reduced subset of the nodes in the network. 286 3. Applicability Statement 288 OLSRv2 is a proactive routing protocol for mobile ad hoc networks 289 (MANETs) [RFC2501]. The larger and more dense a network, the more 290 optimization can be achieved by using MPRs compared to the classic 291 link state algorithm. OLSRv2 enables hop-by-hop routing, i.e. each 292 node using its local information provided by OLSRv2 to route packets. 294 As OLSRv2 continuously maintains routes to all destinations in the 295 network, the protocol is beneficial for traffic patterns where the 296 traffic is random and sporadic between a large subset of nodes, and 297 where the (source, destination) pairs are changing over time. No 298 additional control traffic need be generated in this case since 299 routes are maintained for all known destinations at all times. Also, 300 since routes are maintained continuously, traffic is subject to no 301 delays due to buffering or to route discovery. 303 OLSRv2 supports nodes which have multiple interfaces which 304 participate in the MANET using OLSRv2. As described in [nhdp], each 305 OLSRv2 interface may have one or more network addresses (which may 306 have prefix lengths). OLSRv2, additionally, supports nodes which 307 have non-OLSRv2 interfaces which may be local or can serve as 308 gateways towards other networks. 310 OLSRv2 uses the format specified in [packetbb] for all messages and 311 packets. OLSRv2 is thereby able to allow for extensions via 312 "external" and "internal" extensibility. External extensibility 313 allows a protocol extension to specify and exchange new message 314 types, which can be forwarded and delivered correctly even by nodes 315 which do not support that extension. Internal extensibility allows a 316 protocol extension to define additional attributes to be carried 317 embedded in the standard OLSRv2 control messages detailed in this 318 specification (or any new message types defined by other protocol 319 extensions) using the TLV mechanism specified in [packetbb], while 320 still allowing nodes not supporting that extension to forward 321 messages including the extension, and to process messages ignoring 322 the extension. 324 The OLSRv2 neighborhood discovery protocol using HELLO messages is 325 specified in [nhdp]. This neighborhood discovery protocol serves to 326 ensure that each OLSRv2 node has available continuously updated 327 Information Bases describing the node's 1-hop and symmetric 2-hop 328 neighbors. This neighborhood discovery protocol, which also uses 329 [packetbb], is extended in this document by the addition of MPR 330 information. 332 OLSRv2 does not make any assumption about node addresses, other than 333 that each node is assumed to have at least one unique and routable IP 334 address for each interface that it has which participates in the 335 MANET. 337 OLSRv2 can, as does [nhdp], use the link local multicast address "LL- 338 MANET-Routers", and either the "manet" UDP port or the "manet" IP 339 protocol number, all as specified in [manet-iana]. 341 4. Protocol Overview and Functioning 343 OLSRv2 is a proactive routing protocol for mobile ad hoc networks. 344 The protocol inherits the stability of a link state algorithm and has 345 the advantage of having routes immediately available when needed due 346 to its proactive nature. OLSRv2 is an optimization of the classical 347 link state protocol, tailored for mobile ad hoc networks. The main 348 tailoring and optimizations of OLSRv2 are: 350 o Unacknowledged transmission of all control messages; control 351 messages are sent periodically, but may also be sent in response 352 to changes in the local neighborhood. 354 o MPR flooding for MANET-wide link state information distribution. 356 o Partial topology maintenance - each node knows only a subset of 357 the links in the network, sufficient for a minimum hop route to 358 all destinations. 360 The MPR flooding and partial topology maintenance are based on the 361 concept of MultiPoint Relays (MPRs), selected independently by nodes 362 based on the symmetric 1-hop and 2-hop neighbor information 363 maintained using [nhdp]. 365 Using the message exchange format [packetbb] and the neighborhood 366 discovery protocol [nhdp], OLSRv2 also contains the following main 367 components: 369 o A TLV, to be included within the HELLO messages of [nhdp], 370 allowing a node to signal MPR selection. 372 o The optimized mechanism for MANET-wide information distribution, 373 denoted "MPR flooding". 375 o A specification of MANET-wide signaling, denoted TC (Topology 376 Control) messages. TC messages in OLSRv2 serve to: 378 * inject link state information into the entire MANET; 380 * inject addresses of hosts and networks for which they may serve 381 as a gateway into the entire network. 383 TC messages are emitted periodically, thereby allowing nodes to 384 continuously track changes in the network. Incomplete TC messages 385 may be used to report additions to advertised information without 386 repeating unchanged information. Some TC messages may be MPR 387 flooded over only part of the network, allowing a node to ensure 388 that nearer nodes are kept more up to date than distant nodes, 389 such as is used in Fisheye State Routing [FSR] and Fuzzy Sighted 390 Link State routing [FSLS]. 392 Each node in the network selects a set of MPRs. The MPRs of a node X 393 may be any subset of node X's willing symmetric 1-hop neighbors, such 394 that every node in the symmetric strict 2-hop neighborhood of node X 395 has a symmetric link to at least one of node X's MPRs. The MPRs of a 396 node may thus be said to "cover" the node's symmetric strict 2-hop 397 neighborhood. Each node also maintains information about the set of 398 symmetric 1-hop neighbors that have selected it as an MPR, its MPR 399 selectors. 401 As long as the condition above is satisfied, any algorithm selecting 402 MPRs is acceptable in terms of implementation interoperability. 403 However if smaller sets of MPRs are selected then the greater the 404 efficiency gains that are possible. An analysis and examples of MPR 405 selection algorithms is given in [MPR]. 407 A node may independently determine and advertise its willingness to 408 be selected as an MPR. A node may advertise that it always should be 409 selected as an MPR or that it should never be selected as an MPR. In 410 the latter case, the node will neither relay control messages, nor 411 will that node be included as an intermediate node in any routing 412 table calculations. Use of variable willingness is most effective in 413 dense networks. 415 In OLSRv2, actual efficiency gains are based on the sizes of each 416 node's Relay Set, the set of symmetric 1-hop neighbors for which it 417 is to relay broadcast traffic, and its Advertised Neighbor Set, the 418 set of symmetric 1-hop neighbors for which it is to advertise link 419 state information into the network in TC messages. Each of these 420 sets MUST contain all MPR selectors, and MAY contain additional 421 nodes. If the Advertised Neighbor Set is empty, TC messages are not 422 generated by that node, unless needed for gateway reporting, or for a 423 short period to accelerate the removal of outdated link state 424 information. 426 OLSRv2 is designed to work in a completely distributed manner and 427 does not depend on any central entity. The protocol does not require 428 reliable transmission of control messages; each node sends control 429 messages periodically, and can therefore sustain a reasonable loss of 430 some such messages. Such losses may occur frequently in radio 431 networks due to collisions or other transmission problems. OLSRv2 432 MAY use "jitter", randomized adjustments to message transmission 433 times, to reduce the incidence of collisions [RFC5148]. 435 OLSRv2 does not require sequenced delivery of messages. Each TC 436 message contains a sequence number which is incremented for each 437 message. Thus the recipient of a TC message can, if required, easily 438 identify which information is more recent - even if messages have 439 been re-ordered while in transmission. 441 OLSRv2 only interacts with IP through routing table management. 442 OLSRv2 sends its control messages as described in [packetbb] and 443 [nhdp]. 445 5. Protocol Parameters and Constants 447 The parameters and constants used in this specification are those 448 defined in [nhdp] plus those defined in this section. The separation 449 in [nhdp] into interface parameters, node parameters and constants is 450 also used in OLSRv2, however all but one (RX_HOLD_TIME) of the 451 parameters added by OLSRv2 are node parameters. Parameters may be 452 classified into the following categories: 454 o Local history times 456 o Message intervals 458 o Advertised information validity times 460 o Received message validity times 462 o Jitter times 464 o Hop limits 466 o Willingness 468 In addition, constants for particular cases of a node's willingness 469 to be an MPR are defined. These parameters and constants are 470 detailed in the following sections. As for the parameters in [nhdp], 471 parameters defined in this document may be changed dynamically by a 472 node, and need not be the same on different nodes, even in the same 473 MANET, or on different interfaces of the same node (for interface 474 parameters). 476 5.1. Local History Times 478 The following parameter manages the time for which local information 479 is retained: 481 O_HOLD_TIME - is used to define the time for which a recently used 482 and replaced originator address is used to recognize the node's 483 own messages. 485 The following constraint applies to this parameter: 487 o O_HOLD_TIME >= 0 489 5.2. Message Intervals 491 The following interface parameters regulate TC message transmissions 492 by a node. TC messages are usually sent periodically, but MAY also 493 be sent in response to changes in the node's Advertised Neighbor Set 494 and Local Attached Network Set. With a larger value of the parameter 495 TC_INTERVAL, and a smaller value of the parameter TC_MIN_INTERVAL, TC 496 messages may more often be transmitted in response to changes in a 497 highly dynamic network. However because a node has no knowledge of, 498 for example, nodes remote to it joining the network, TC messages MUST 499 NOT be sent purely responsively. 501 TC_INTERVAL - is the maximum time between the transmission of two 502 successive TC messages by this node. When no TC messages are sent 503 in response to local network changes (by design, or because the 504 local network is not changing) then TC messages SHOULD be sent at 505 a regular interval TC_INTERVAL, possibly modified by jitter as 506 specified in [RFC5148]. 508 TC_MIN_INTERVAL - is the minimum interval between transmission of 509 two successive TC messages by this node. (This minimum interval 510 MAY be modified by jitter, as specified in [RFC5148].) 512 The following constraints apply to these parameters: 514 o TC_INTERVAL > 0 516 o TC_MIN_INTERVAL >= 0 518 o TC_INTERVAL >= TC_MIN_INTERVAL 520 o If INTERVAL_TIME TLVs as defined in [timetlv] are included in TC 521 messages, then TC_INTERVAL MUST be representable as described in 522 [timetlv]. 524 5.3. Advertised Information Validity Times 526 The following parameters manage the validity time of information 527 advertised in TC messages: 529 T_HOLD_TIME - is used to define the minimum value in the 530 VALIDITY_TIME TLV included in all TC messages sent by this node. 531 If a single value of parameter TC_HOP_LIMIT (see Section 5.6) is 532 used then this will be the only value in that TLV. 534 A_HOLD_TIME - is the period during which TC messages are sent after 535 they no longer have any advertised information to report, but are 536 sent in order to accelerate outdated information removal by other 537 nodes. 539 The following constraints apply to these parameters: 541 o T_HOLD_TIME > 0 543 o A_HOLD_TIME >= 0 545 o T_HOLD_TIME >= TC_INTERVAL 547 o If TC messages can be lost, then both T_HOLD_TIME and A_HOLD_TIME 548 SHOULD be significantly greater than TC_INTERVAL; a value >= 3 x 549 TC_INTERVAL is RECOMMENDED. 551 o T_HOLD_TIME MUST be representable as described in [timetlv]. 553 5.4. Received Message Validity Times 555 The following parameters manage the validity time of recorded 556 received message information: 558 RX_HOLD_TIME - is an interface parameter, and is the period after 559 receipt of a message by the appropriate OLSRv2 interface of this 560 node for which that information is recorded, in order that the 561 message is recognized as having been previously received on this 562 OLSRv2 interface. 564 P_HOLD_TIME - is the period after receipt of a message which is 565 processed by this node for which that information is recorded, in 566 order that the message is not processed again if received again. 568 F_HOLD_TIME - is the period after receipt of a message which is 569 forwarded by this node for which that information is recorded, in 570 order that the message is not forwarded again if received again. 572 The following constraints apply to these parameters: 574 o RX_HOLD_TIME > 0 576 o P_HOLD_TIME > 0 578 o F_HOLD_TIME > 0 580 o All of these parameters SHOULD be greater than the maximum 581 difference in time that a message may take to traverse the MANET, 582 taking into account any message forwarding jitter as well as 583 propagation, queuing, and processing delays. 585 5.5. Jitter 587 If jitter, as defined in [RFC5148], is used then these parameters are 588 as follows: 590 TP_MAXJITTER - represents the value of MAXJITTER used in [RFC5148] 591 for periodically generated TC messages sent by this node. 593 TT_MAXJITTER - represents the value of MAXJITTER used in [RFC5148] 594 for externally triggered TC messages sent by this node. 596 F_MAXJITTER - represents the default value of MAXJITTER used in 597 [RFC5148] for messages forwarded by this node. However before 598 using F_MAXJITTER a node MAY attempt to deduce a more appropriate 599 value of MAXJITTER, for example based on any INTERVAL_TIME or 600 VALIDITY_TIME TLVs contained in the message to be forwarded. 602 For constraints on these parameters see [RFC5148]. 604 5.6. Hop Limit Parameter 606 The parameter TC_HOP_LIMIT is the hop limit set in each TC message. 607 TC_HOP_LIMIT MAY be a single fixed value, or MAY be different in TC 608 messages sent by the same node. However each other node, at any hop 609 count distance, SHOULD see a regular pattern of TC messages, in order 610 that meaningful values of INTERVAL_TIME and VALIDITY_TIME TLVs at 611 each hop count distance can be included as defined in [timetlv]. 612 Thus the pattern of TC_HOP_LIMIT SHOULD be defined to have this 613 property. For example the repeating pattern (255 4 4) satisfies this 614 property (having period TC_INTERVAL at hop counts up to 4, inclusive, 615 and 3 x TC_INTERVAL at hop counts greater than 4), but the repeating 616 pattern (255 255 4 4) does not satisfy this property because at hop 617 counts greater than 4, message intervals are alternately TC_INTERVAL 618 and 3 x TC_INTERVAL. 620 The following constraints apply to this parameter: 622 o The maximum value of TC_HOP_LIMIT >= the network diameter in hops, 623 a value of 255 is RECOMMENDED. 625 o All values of TC_HOP_LIMIT >= 2. 627 5.7. Willingness 629 Each node has a WILLINGNESS parameter, which MUST be in the range 630 WILL_NEVER to WILL_ALWAYS, inclusive, and represents its willingness 631 to be an MPR, and hence its willingness to forward messages and be an 632 intermediate node on routes. If a node has WILLINGNESS == WILL_NEVER 633 it does not perform these tasks. A MANET using OLSRv2 with too many 634 nodes with WILLINGNESS == WILL_NEVER will not function; it MUST be 635 ensured, by administrative or other means, that this does not happen. 637 Nodes MAY have different WILLINGNESS values; however the three 638 constants WILL_NEVER, WILL_DEFAULT and WILL_ALWAYS MUST have the 639 values defined in Section 5.7. (Use of WILLINGNESS == WILL_DEFAULT 640 allows a node to avoid including an MPR_WILLING TLV in its TC 641 messages, use of WILLINGNESS == WILL_ALWAYS means that a node will 642 always be selected as an MPR by all symmetric 1-hop neighbors.) 644 The following constraints apply to this parameter: 646 o WILLINGNESS >= WILL_NEVER 648 o WILLINGNESS <= WILL_ALWAYS 650 5.8. Parameter Change Constraints 652 This section presents guidelines, applicable if protocol parameters 653 are changed dynamically. 655 O_HOLD_TIME 657 * If O_HOLD_TIME for a node changes, then O_time for all 658 Originator Tuples MAY be changed. 660 TC_INTERVAL 662 * If the TC_INTERVAL for a node increases, then the next TC 663 message generated by this node MUST be generated according to 664 the previous, shorter, TC_INTERVAL. Additional subsequent TC 665 messages MAY be generated according to the previous, shorter, 666 TC_INTERVAL. 668 * If the TC_INTERVAL for a node decreases, then the following TC 669 messages from this node MUST be generated according to the 670 current, shorter, TC_INTERVAL. 672 RX_HOLD_TIME 674 * If RX_HOLD_TIME for an OLSRv2 interface changes, then RX_time 675 for all Received Tuples for that OLSRv2 interface MAY be 676 changed. 678 P_HOLD_TIME 680 * If P_HOLD_TIME changes, then P_time for all Processed Tuples 681 MAY be changed. 683 F_HOLD_TIME 685 * If F_HOLD_TIME changes, then F_time for all Forwarded Tuples 686 MAY be changed. 688 TP_MAXJITTER 690 * If TP_MAXJITTER changes, then the periodic TC message schedule 691 on this node MAY be changed immediately. 693 TT_MAXJITTER 695 * If TT_MAXJITTER changes, then externally triggered TC messages 696 on this node MAY be rescheduled. 698 F_MAXJITTER 700 * If F_MAXJITTER changes, then TC messages waiting to be 701 forwarded with a delay based on this parameter MAY be 702 rescheduled. 704 TC_HOP_LIMIT 706 * If TC_HOP_LIMIT changes, and the node uses multiple values 707 after the change, then message intervals and validity times 708 included in TC messages MUST be respected. The simplest way to 709 do this is to start any new repeating pattern of TC_HOP_LIMIT 710 values with its largest value. 712 6. Information Bases 714 Each node maintains the Information Bases described in the following 715 sections. These are used for describing the protocol in this 716 document. An implementation of this protocol MAY maintain this 717 information in the indicated form, or in any other organization which 718 offers access to this information. In particular note that it is not 719 necessary to remove Tuples from Sets at the exact time indicated, 720 only to behave as if the Tuples were removed at that time. 722 The purpose of OLSRv2 is to determine the Routing Set, which may be 723 used to update IP's Routing Table, providing "next hop" routing 724 information for IP datagrams. OLSRv2 maintains the following 725 Information Bases: 727 Local Information Base - as defined in [nhdp], extended by the 728 addition of an Originator Set, defined in Section 6.1.1 and a 729 Local Attached Network Set, defined in Section 6.1.2. 731 Interface Information Bases - as defined in [nhdp], one Interface 732 Information Base for each OLSRv2 interface. 734 Node Information Base - as defined in [nhdp], extended by the 735 addition of three elements to each Neighbor Tuple, as defined in 736 Section 6.2. 738 Topology Information Base - this Information Base is specific to 739 OLSRv2, and is defined in Section 6.3. 741 Processing and Forwarding Information Base - this Information Base 742 is specific to OLSRv2, and is defined in Section 6.4. 744 The ordering of sequence numbers, when considering which is the 745 greater, is as defined in Section 18. 747 6.1. Local Information Base 749 The Local Information Base as defined in [nhdp] is extended by the 750 addition of an Originator Set, defined in Section 6.1.1, and a Local 751 Attached Network Set, defined in Section 6.1.2. 753 6.1.1. Originator Set 755 A node's Originator Set records addresses that were recently 756 originator addresses. If a node's originator address is immutable 757 then this set is always empty and MAY be omitted. It consists of 758 Originator Tuples: 760 (O_orig_addr, O_time) 762 where: 764 O_orig_addr is a recently used originator address; 766 O_time specifies the time at which this Tuple expires and MUST be 767 removed. 769 6.1.2. Local Attached Network Set 771 A node's Local Attached Network Set records its local non-OLSRv2 772 interfaces that can act as gateways to other networks. The Local 773 Attached Network Set is not modified by this protocol. This protocol 774 MAY respond to changes to the Local Attached Network Set, which MUST 775 reflect corresponding changes in the node's status. It consists of 776 Local Attached Network Tuples: 778 (AL_net_addr, AL_dist) 780 where: 782 AL_net_addr is the network address of an attached network which can 783 be reached via this node. 785 AL_dist is the number of hops to the network with address 786 AL_net_addr from this node. 788 Attached networks local to this node SHOULD be treated as local non- 789 MANET interfaces, and added to the Local Interface Set, as specified 790 in [nhdp], rather than being added to the Local Attached Network Set. 792 An attached network MAY also be attached to other nodes. 794 It is not the responsibility of OLSRv2 to maintain routes from this 795 node to networks recorded in the Local Attached Network Set. 797 6.2. Node Information Base 799 Each Neighbor Tuple in the Neighbor Set, defined in [nhdp], has these 800 additional elements: 802 N_willingness is the node's willingness to be selected as an MPR, in 803 the range from WILL_NEVER to WILL_ALWAYS, both inclusive; 805 N_mpr is a boolean flag, describing if this neighbor is selected as 806 an MPR by this node; 808 N_mpr_selector is a boolean flag, describing if this neighbor has 809 selected this node as an MPR, i.e. is an MPR selector of this 810 node. 812 6.3. Topology Information Base 814 The Topology Information Base stores information required for the 815 generation and processing of TC messages, and information received in 816 TC messages. The Advertised Neighbor Set contains interface 817 addresses of symmetric 1-hop neighbors which are to be reported in TC 818 messages. The Advertising Remote Node Set, the Topology Set and the 819 Attached Network Set record information received in TC messages. 821 Additionally, a Routing Set is maintained, derived from the 822 information recorded in the Neighborhood Information Base, Topology 823 Set, Attached Network Set and Advertising Remote Node Set. 825 6.3.1. Advertised Neighbor Set 827 A node's Advertised Neighbor Set contains interface addresses of 828 symmetric 1-hop neighbors which are to be advertised through TC 829 messages: 831 {A_neighbor_iface_addr} 833 In addition, an Advertised Neighbor Set Sequence Number (ANSN) is 834 maintained. Each time the Advertised Neighbor Set is updated, the 835 ANSN MUST be incremented. The ANSN MUST also be incremented if there 836 is a change to the set of Local Attached Network Tuples that are to 837 be advertised in the node's TC messages. 839 6.3.2. Advertising Remote Node Set 841 A node's Advertising Remote Node Set records information describing 842 each remote node in the network that transmits TC messages. It 843 consists of Advertising Remote Node Tuples: 845 (AR_orig_addr, AR_seq_number, AR_iface_addr_list, AR_time) 847 where: 849 AR_orig_addr is the originator address of a received TC message, 850 note that this does not include a prefix length; 852 AR_seq_number is the greatest ANSN in any TC message received which 853 originated from the node with originator address AR_orig_addr 854 (i.e. which contributed to the information contained in this 855 Tuple); 857 AR_iface_addr_list is an unordered list of the interface addresses 858 of the node with originator address AR_orig_addr; 860 AR_time is the time at which this Tuple expires and MUST be removed. 862 6.3.3. Topology Set 864 A node's Topology Set records topology information about the network. 865 It consists of Topology Tuples: 867 (T_dest_iface_addr, T_orig_addr, T_seq_number, T_time) 869 where: 871 T_dest_iface_addr is an interface address of a destination node, 872 which may be reached in one hop from the node with originator 873 address T_orig_addr; 875 T_orig_addr is the originator address of a node which is the last 876 hop on a path towards the node with interface address 877 T_dest_iface_addr, note that this does not include a prefix 878 length; 880 T_seq_number is the greatest ANSN in any TC message received which 881 originated from the node with originator address T_orig_addr (i.e. 882 which contributed to the information contained in this Tuple); 884 T_time specifies the time at which this Tuple expires and MUST be 885 removed. 887 6.3.4. Attached Network Set 889 A node's Attached Network Set records information about networks 890 attached to other nodes. It consists of Attached Network Tuples: 892 (AN_net_addr, AN_orig_addr, AN_dist, AN_seq_number, AN_time) 894 where: 896 AN_net_addr is the network address of an attached network, which may 897 be reached via the node with originator address AN_orig_addr; 899 AN_orig_addr is the originator address of a node which can act as 900 gateway to the network with address AN_net_addr, note that this 901 does not include a prefix length; 903 AN_dist is the number of hops to the network with address 904 AN_net_addr from the node with originator address AN_orig_addr; 906 AN_seq_number is the greatest ANSN in any TC message received which 907 originated from the node with originator address AN_orig_addr 908 (i.e. which contributed to the information contained in this 909 Tuple); 911 AN_time specifies the time at which this Tuple expires and MUST be 912 removed. 914 6.3.5. Routing Set 916 A node's Routing Set records the selected path to each destination 917 for which a route is known. It consists of Routing Tuples: 919 (R_dest_addr, R_next_iface_addr, R_dist, R_local_iface_addr) 921 where: 923 R_dest_addr is the address of the destination, either the address of 924 an interface of a destination node, or the network address of an 925 attached network; 927 R_next_iface_addr is the OLSRv2 interface address of the "next hop" 928 on the selected path to the destination; 930 R_dist is the number of hops on the selected path to the 931 destination; 933 R_local_iface_addr is the address of the local OLSRv2 interface over 934 which a packet MUST be sent to reach the destination by the 935 selected path. 937 6.4. Processing and Forwarding Information Base 939 The Processing and Forwarding Information Base records information 940 required to ensure that a message is processed at most once and is 941 forwarded at most once per OLSRv2 interface of a node, using MPR 942 flooding. 944 6.4.1. Received Set 946 A node has a Received Set per local OLSRv2 interface. Each Received 947 Set records the signatures of messages which have been received over 948 that OLSRv2 interface. Each consists of Received Tuples: 950 (RX_type, RX_orig_addr, RX_seq_number, RX_time) 952 where: 954 RX_type is the received message type, or zero if the received 955 message sequence number is not type-specific; 957 RX_orig_addr is the originator address of the received message; 959 RX_seq_number is the message sequence number of the received 960 message; 962 RX_time specifies the time at which this Tuple expires and MUST be 963 removed. 965 6.4.2. Processed Set 967 A node's Processed Set records signatures of messages which have been 968 processed by the node. It consists of Processed Tuples: 970 (P_type, P_orig_addr, P_seq_number, P_time) 972 where: 974 P_type is the processed message type, or zero if the processed 975 message sequence number is not type-specific; 977 P_orig_addr is the originator address of the processed message; 979 P_seq_number is the message sequence number of the processed 980 message; 982 P_time specifies the time at which this Tuple expires and MUST be 983 removed. 985 6.4.3. Forwarded Set 987 A node's Forwarded Set records signatures of messages which have been 988 processed by the node. It consists of Forwarded Tuples: 990 (F_type, F_orig_addr, F_seq_number, F_time) 992 where: 994 F_type is the forwarded message type, or zero if the forwarded 995 message sequence number is not type-specific; 997 F_orig_addr is the originator address of the forwarded message; 999 F_seq_number is the message sequence number of the forwarded 1000 message; 1002 F_time specifies the time at which this Tuple expires and MUST be 1003 removed. 1005 6.4.4. Relay Set 1007 A node has a Relay Set per local OLSRv2 interface. Each Relay Set 1008 records the OLSRv2 interface addresses of symmetric 1-hop neighbors, 1009 such that the node is to forward messages received from those 1010 neighbors' OLSRv2 interfaces, on that local OLSRv2 interface, if not 1011 otherwise excluded from forwarding that message (e.g. by it having 1012 been previously forwarded): 1014 {RY_neighbor_iface_addr} 1016 7. Packet Processing and Message Forwarding 1018 On receiving a packet, as defined in [packetbb], a node examines the 1019 packet header and each of the message headers. If the message type 1020 is known to the node, the message is processed locally according to 1021 the specification for that message type. The message is also 1022 independently evaluated for forwarding. 1024 7.1. Actions when Receiving an OLSRv2 Packet 1026 On receiving a packet, a node MUST perform the following tasks: 1028 1. The packet MAY be fully parsed on reception, or the packet and 1029 its messages MAY be parsed only as required. (It is possible to 1030 parse the packet header, or determine its absence, without 1031 parsing any messages. It is possible to divide the packet into 1032 messages without fully parsing the message headers. It is 1033 possible to determine whether a message is to be forwarded, and 1034 to forward it, without parsing its body. It is possible to 1035 determine whether a message is to be processed without parsing 1036 its body.) 1038 2. If parsing fails at any point the relevant entity (packet or 1039 message) MUST be silently discarded, other parts of the packet 1040 (up to the whole packet) MAY be silently discarded. 1042 3. Otherwise: 1044 1. If the packet header is present and it contains a packet TLV 1045 block, then each TLV in it is processed according to its type 1046 if recognized, otherwise the TLV is ignored. 1048 2. Otherwise each message in the packet, if any, is treated 1049 according to Section 7.2. 1051 7.2. Actions when Receiving an OLSRv2 Message 1053 A node MUST perform the following tasks for each received message: 1055 1. If the message header cannot be correctly parsed according to the 1056 specification in [packetbb], or if the node recognizes from the 1057 originator address of the message that the message is one which 1058 the receiving node itself originated (i.e. is the current 1059 originator address of the node, or is an O_orig_addr in an 1060 Originator Tuple) then the message MUST be silently discarded. 1062 2. Otherwise: 1064 1. If the message is a HELLO message, then the message is 1065 processed according to Section 10. 1067 2. Otherwise: 1069 1. Define the "dependent message type" of the message to 1070 equal the message type if the mistypedep flag bit in the 1071 message header is set ('1'), or otherwise to equal a 1072 value "type-independent" which is not in the range 0 to 1073 255. 1075 2. If the message is of a known type, including being a TC 1076 message, then the message is considered for processing 1077 according to Section 7.3, AND; 1079 3. If for the message: 1081 - is present and > 1, AND; 1083 - is not present or < 255 1085 then the message is considered for forwarding according 1086 to Section 7.4. 1088 7.3. Message Considered for Processing 1090 If a message (the "current message") is considered for processing, 1091 then the following tasks MUST be performed: 1093 1. If a Processed Tuple exists with: 1095 * P_type == the dependent message type of the current message, 1096 AND; 1098 * P_orig_addr == the originator address of the current message, 1099 AND; 1101 * P_seq_number == the message sequence number of the current 1102 message; 1104 then the current message MUST NOT be processed. 1106 2. Otherwise: 1108 1. Create a Processed Tuple with: 1110 + P_type = the dependent message type of the current 1111 message; 1113 + P_orig_addr = the originator address of the current 1114 message; 1116 + P_seq_number = the sequence number of the current message; 1118 + P_time = current time + P_HOLD_TIME. 1120 2. Process the current message according to its type. 1122 7.4. Message Considered for Forwarding 1124 If a message is considered for forwarding, and it is either of a 1125 message type defined in this document (i.e. is a TC message) or of an 1126 unknown message type, then it MUST use the following algorithm. A 1127 message of a message type not defined in this document MAY, in an 1128 extension to this protocol, specify the use of this, or another 1129 algorithm. (Such an other algorithm MAY use the Received Set for the 1130 receiving interface, it SHOULD use the Forwarded Set similarly to the 1131 following algorithm.) 1133 If a message (the "current message") is considered for forwarding 1134 according to this algorithm, the following tasks MUST be performed: 1136 1. If the sending interface address (the source address of the IP 1137 datagram containing the current message) does not match (taking 1138 into account any address prefix) an OLSRv2 interface address in 1139 an L_neighbor_iface_addr_list of a Link Tuple, with L_status == 1140 SYMMETRIC, in the Link Set for the OLSRv2 interface on which the 1141 current message was received (the "receiving interface") then the 1142 current message MUST be silently discarded. 1144 2. Otherwise: 1146 1. If a Received Tuple exists in the Received Set for the 1147 receiving interface, with: 1149 + RX_type == the dependent message type of the current 1150 message, AND; 1152 + RX_orig_addr == the originator address of the current 1153 message, AND; 1155 + RX_seq_number == the sequence number of the current 1156 message; 1158 then the current message MUST be silently discarded. 1160 2. Otherwise: 1162 1. Create a Received Tuple in the Received Set for the 1163 receiving interface with: 1165 - RX_type = the dependent message type of the current 1166 message; 1168 - RX_orig_addr = originator address of the current 1169 message; 1171 - RX_seq_number = sequence number of the current 1172 message; 1174 - RX_time = current time + RX_HOLD_TIME. 1176 2. If a Forwarded Tuple exists with: 1178 - F_type == the dependent message type of the current 1179 message, AND; 1181 - F_orig_addr == the originator address of the current 1182 message, AND; 1184 - F_seq_number == the sequence number of the current 1185 message. 1187 then the current message MUST be silently discarded. 1189 3. Otherwise if the sending interface address matches 1190 (taking account of any address prefix) an 1191 RY_neighbor_iface_addr in the Relay Set for the receiving 1192 interface, then: 1194 1. Create a Forwarded Tuple with: 1196 o F_type = the dependent message type of the current 1197 message; 1199 o F_orig_addr = originator address of the current 1200 message; 1202 o F_seq_number = sequence number of the current 1203 message; 1205 o F_time = current time + F_HOLD_TIME. 1207 2. The message header of the current message is modified 1208 by: 1210 o decrement in the message header by 1; 1212 o increment in the message header by 1. 1214 3. For each OLSRv2 interface of the node, include the 1215 message in a packet to be transmitted on that OLSRv2 1216 interface, as described in Section 8. This packet 1217 may contain other forwarded messages and/or messages 1218 generated by this node. Forwarded messages may be 1219 jittered as described in [RFC5148]. The value of 1220 MAXJITTER used in jittering a forwarded message MAY 1221 be based on information in that message (in 1222 particular any INTERVAL_TIME or VALIDITY_TIME TLVs in 1223 that message) or otherwise SHOULD be with a maximum 1224 delay of F_MAXJITTER. A node MAY modify the jitter 1225 applied to a message in order to more efficiently 1226 combine messages in packets, as long as the maximum 1227 jitter is not exceeded. 1229 8. Packets and Messages 1231 Nodes using OLSRv2 exchange information through messages. One or 1232 more messages sent by a node at the same time SHOULD be combined into 1233 a single packet. These messages may have originated at the sending 1234 node, or have originated at another node and are forwarded by the 1235 sending node. Messages with different originating nodes MAY be 1236 combined in the same packet. Messages from other protocols defined 1237 using [packetbb] MAY be combined in the same packet. 1239 The packet and message format used by OLSRv2 is defined in 1240 [packetbb], where: 1242 o OLSRv2 packets MAY include packet TLVs, however OLSRv2 itself does 1243 not specify any packet TLVs. 1245 o All references in this specification to TLVs that do not indicate 1246 a type extension, assume Type Extension == 0. TLVs in processed 1247 messages with a type extension which is neither zero as so 1248 assumed, nor a specifically indicated non-zero type extension, are 1249 ignored. 1251 Other options defined in [packetbb] may be freely used, in particular 1252 any other values of , , or consistent with their specifications. 1255 The remainder of this section defines, within the framework of 1256 [packetbb], message types and TLVs specific to OLSRv2. 1258 8.1. HELLO Messages 1260 A HELLO message in OLSRv2 is generated as specified in [nhdp]. 1261 Additionally, an OLSRv2 node: 1263 o MUST include TLV(s) with Type == MPR associated with all OLSRv2 1264 interface addresses that: 1266 * are included in the HELLO message associated with a TLV with 1267 Type == LINK_STATUS and Value == SYMMETRIC; AND 1269 * are included in a Neighbor Tuple with N_mpr == true. 1271 If there is more than one copy of such an address in the HELLO 1272 message, then this applies to the specific copy of the address 1273 with which the LINK_STATUS TLV is associated. 1275 o MUST NOT include any TLVs with Type == MPR associated with any 1276 other addresses. 1278 o MAY include a message TLV with Type == MPR_WILLING, indicating the 1279 node's willingness to be selected as an MPR. 1281 8.1.1. HELLO Message TLVs 1283 In a HELLO message, a node MUST include an MPR_WILLING message TLV as 1284 specified in Table 1, unless WILLINGNESS == WILL_DEFAULT (in which 1285 case it MAY be included). A node MUST NOT include more than one 1286 MPR_WILLING message TLV. 1288 +-------------+--------------+--------------------------------------+ 1289 | Type | Value Length | Value | 1290 +-------------+--------------+--------------------------------------+ 1291 | MPR_WILLING | 1 octet | Node parameter WILLINGNESS; unused | 1292 | | | bits (based on the maximum | 1293 | | | willingness value WILL_ALWAYS) are | 1294 | | | RESERVED and SHOULD be set to zero. | 1295 +-------------+--------------+--------------------------------------+ 1297 Table 1 1299 If a node does not advertise an MPR_WILLING TLV in a HELLO message, 1300 then the node MUST be assumed to have WILLINGNESS equal to 1301 WILL_DEFAULT. 1303 8.1.2. HELLO Message Address Block TLVs 1305 In a HELLO message, a node MAY include MPR address block TLV(s) as 1306 specified in Table 2. 1308 +------+--------------+-------+ 1309 | Type | Value Length | Value | 1310 +------+--------------+-------+ 1311 | MPR | 0 octets | None. | 1312 +------+--------------+-------+ 1314 Table 2 1316 8.2. TC Messages 1318 A TC message MUST contain: 1320 o , and elements in its 1321 message header, as specified in [packetbb]. 1323 o A element in its message header if the message 1324 contains either a VALIDITY_TIME or an INTERVAL_TIME TLV indicating 1325 more than one time value according to distance. 1327 o A single message TLV with Type == CONT_SEQ_NUM, and Type Extension 1328 == COMPLETE or Type Extension == INCOMPLETE, as specified in 1329 Section 8.2.1 (for complete and incomplete TC messages, 1330 respectively). 1332 o A message TLV with Type == VALIDITY_TIME, as specified in 1333 [timetlv]. The options included in [timetlv] for representing 1334 zero and infinite times MUST NOT be used. 1336 o All of the node's interface addresses. These MUST be included in 1337 the message's address blocks, unless: 1339 * the node has a single interface, with a single interface 1340 address with maximum prefix length, and 1342 * that address is the node's originator address. 1344 In this exceptional case, the address will be included as the 1345 message's originator address, and MAY be omitted from the 1346 message's address blocks. 1348 o TLV(s) with Type == LOCAL_IF and Value == UNSPEC_IF associated 1349 with all of the node's interface addresses. 1351 o If the TC message is complete, all addresses in the Advertised 1352 Address Set and all addresses in the Local Attached Network Set, 1353 the latter (only) with associated GATEWAY address block TLV(s), as 1354 specified in Section 8.2.2. 1356 A TC message SHOULD have the mistypedep bit of , as 1357 defined in [packetbb], cleared ('0'). 1359 A TC message MAY contain: 1361 o If the TC message is incomplete, any addresses in the Advertised 1362 Address Set and any addresses in the Local Attached Network Set, 1363 the latter (only) with associated GATEWAY address block TLV(s), as 1364 specified in Section 8.2.2. 1366 o A message TLV with Type == INTERVAL_TIME, as specified in 1367 [timetlv]. The options included in [timetlv] for representing 1368 zero and infinite times MUST NOT be used. 1370 8.2.1. TC Message TLVs 1372 In a TC message, a node MUST include a single CONT_SEQ_NUM message 1373 TLV, as specified in Table 3, and with Type Extension == COMPLETE or 1374 Type Extension == INCOMPLETE, according to whether the TC message is 1375 complete or incomplete. 1377 +--------------+--------------+-------------------------------------+ 1378 | Type | Value Length | Value | 1379 +--------------+--------------+-------------------------------------+ 1380 | CONT_SEQ_NUM | 1 octet | The ANSN contained in the | 1381 | | | Advertised Neighbor Set. | 1382 +--------------+--------------+-------------------------------------+ 1384 Table 3 1386 8.2.2. TC Message Address Block TLVs 1388 In a TC message, a node MAY include GATEWAY address block TLV(s) as 1389 specified in Table 4. 1391 +---------+--------------+-------------------------------------+ 1392 | Type | Value Length | Value | 1393 +---------+--------------+-------------------------------------+ 1394 | GATEWAY | 1 octet | Number of hops to attached network. | 1395 +---------+--------------+-------------------------------------+ 1397 Table 4 1399 GATEWAY address block TLV(s) MUST be associated with all attached 1400 network addresses, and MUST NOT be associated with any other 1401 addresses. 1403 9. HELLO Message Generation 1405 An OLSRv2 HELLO message is composed and generated as defined in 1406 [nhdp], with the following additions: 1408 o A message TLV with Type == MPR_WILLING and Value == the node 1409 parameter WILLINGNESS MUST be included, unless WILLINGNESS == 1410 WILL_DEFAULT (in which case it MAY be included). 1412 o For each address which is included in the message with an 1413 associated TLV with Type == LINK_STATUS and Value == SYMMETRIC, 1414 and is of an MPR (i.e. the address is in the 1415 N_neighbor_iface_addr_list of a Neighbor Tuple with N_mpr == 1416 true), an address block TLV with Type == MPR MUST be included. 1417 This TLV MUST be associated with the same copy of the address as 1418 is the TLV with Type == LINK_STATUS. 1420 o For each address which is included in the message and is not 1421 associated with a TLV with Type == LINK_STATUS and Value == 1422 SYMMETRIC, or is not of an MPR (i.e. the address is not in the 1423 N_neighbor_iface_addr_list of a Neighbor Tuple with N_mpr == 1424 true), an address block TLV with Type == MPR MUST NOT be 1425 associated with any copy of this address. 1427 o An additional HELLO message MAY be sent when the node's set of 1428 MPRs changes, in addition to the cases specified in [nhdp], and 1429 subject to the same constraints. 1431 9.1. HELLO Message: Transmission 1433 HELLO messages are included in packets as specified in [packetbb]. 1434 These packets may contain other messages, including TC messages. 1436 10. HELLO Message Processing 1438 Subsequent to the processing of HELLO messages, as specified in 1439 [nhdp], the node MUST identify the Neighbor Tuple which was created 1440 or updated by the processing specified in [nhdp] (the "current 1441 Neighbor Tuple") and update N_willingness as described in 1442 Section 10.1 and N_mpr_selector as described in Section 10.2. 1443 Following these, the node MUST also perform the processing defined in 1444 Section 10.3. 1446 10.1. Updating Willingness 1448 N_willingness in the current Neighbor Tuple is updated as follows: 1450 1. If the HELLO message contains a message TLV with Type == 1451 MPR_WILLING then N_willingness is set to the value of that TLV; 1453 2. Otherwise, N_willingness is set to WILL_DEFAULT. 1455 10.2. Updating MPR Selectors 1457 N_mpr_selector is updated as follows: 1459 1. If a node finds any of its local OLSRv2 interface addresses with 1460 an associated TLV with Type == MPR in the HELLO message 1461 (indicating that the originator node has selected the receiving 1462 node as an MPR), then N_mpr_selector in the current Neighbor 1463 Tuple is set true. 1465 2. Otherwise, if a node finds any of its own interface addresses 1466 with an associated TLV with Type == LINK_STATUS and Value == 1467 SYMMETRIC in the HELLO message, then N_mpr_selector in the 1468 current Neighbor Tuple is set false. 1470 10.3. Symmetric 1-Hop and 2-Hop Neighborhood Changes 1472 A node MUST also perform the following: 1474 1. If N_symmetric of a Neighbor Tuple changes from true to false, 1475 then N_mpr_selector of that Neighbor Tuple MUST be set false. 1477 2. The set of MPRs of a node MUST be recalculated if: 1479 * a Link Tuple is added with L_status == SYMMETRIC, OR; 1481 * a Link Tuple with L_status == SYMMETRIC is removed, OR; 1482 * a Link Tuple with L_status == SYMMETRIC changes to having 1483 L_status == HEARD or L_status == LOST, OR; 1485 * a Link Tuple with L_status == HEARD or L_status == LOST 1486 changes to having L_status == SYMMETRIC, OR; 1488 * a 2-Hop Tuple is added or removed, OR; 1490 * the N_willingness of a Neighbor Tuple with N_symmetric == true 1491 changes from WILL_NEVER to any other value, OR; 1493 * the N_willingness of a Neighbor Tuple with N_symmetric == true 1494 and N_mpr == true changes to WILL_NEVER from any other value, 1495 OR; 1497 * the N_willingness of a Neighbor Tuple with N_symmetric == true 1498 and N_mpr == false changes to WILL_ALWAYS from any other 1499 value. 1501 3. Otherwise the set of MPRs of a node MAY be recalculated if the 1502 N_willingness of a Neighbor Tuple with N_symmetric == true 1503 changes in any other way; it SHOULD be recalculated if N_mpr == 1504 false and this is an increase in N_willingness or if N_mpr == 1505 true and this is a decrease in N_willingness. 1507 If the set of MPRs of a node is recalculated, this MUST be as 1508 described in Section 14. Before that calculation, the N_mpr of all 1509 Neighbor Tuples are set false. After that calculation the N_mpr of 1510 all Neighbor Tuples representing symmetric 1-hop neighbors which are 1511 chosen as MPRs, are set true. 1513 11. TC Message Generation 1515 A node with one or more OLSRv2 interfaces, and with a non-empty 1516 Advertised Neighbor Set or a non-empty Local Attached Network Set 1517 MUST generate TC messages. A node with an empty Advertised Neighbor 1518 Set and empty Local Attached Network Set SHOULD also generate "empty" 1519 TC messages for a period A_HOLD_TIME after it last generated a non- 1520 empty TC message. TC messages (non-empty and empty) are generated 1521 according to the following: 1523 1. The message hop count, if included, MUST be set to zero. 1525 2. The message hop limit MUST be set to a value greater than 1. A 1526 node MAY use the same hop limit TC_HOP_LIMIT in all TC messages, 1527 or use different values of the hop limit TC_HOP_LIMIT in TC 1528 messages, see Section 5.6. 1530 3. The message MUST contain a message TLV with Type == CONT_SEQ_NUM 1531 and Value == ANSN from the Advertised Neighbor Set. If the TC 1532 message is complete then this message TLV MUST have Type 1533 Extension == COMPLETE, otherwise it MUST have Type Extension == 1534 INCOMPLETE. 1536 4. The message MUST contain a message TLV with Type == 1537 VALIDITY_TIME, as specified in [timetlv]. If all TC messages are 1538 sent with the same hop limit then this TLV MUST have Value == 1539 T_HOLD_TIME. If TC messages are sent with different hop limits 1540 (more than one value of TC_HOP_LIMIT) then this TLV MUST specify 1541 times which vary with the number of hops distance appropriate to 1542 the chosen pattern of TC message hop limits, as specified in 1543 [timetlv], these times SHOULD be appropriate multiples of 1544 T_HOLD_TIME. 1546 5. The message MAY contain a message TLV with Type == INTERVAL_TIME, 1547 as specified in [timetlv]. If all TC messages are sent with the 1548 same hop limit then this TLV MUST have Value == TC_INTERVAL. If 1549 TC messages are sent with different hop limits, then this TLV 1550 MUST specify times which vary with the number of hops distance 1551 appropriate to the chosen pattern of TC message hop limits, as 1552 specified in [timetlv], these times SHOULD be appropriate 1553 multiples of TC_INTERVAL. 1555 6. Unless the node has a single interface, with a single interface 1556 address with maximum prefix length, and that address is the 1557 node's originator address, the message MUST contain all of the 1558 node's interface addresses (i.e. all addresses in an 1559 I_local_iface_addr_list) in its address blocks. 1561 7. All addresses of the node's interfaces that are included in an 1562 address block MUST be associated with a TLV with Type == LOCAL_IF 1563 and Value == UNSPEC_IF. 1565 8. A complete message MUST include, and an incomplete message MAY 1566 include, in its address blocks: 1568 1. Each A_neighbor_iface_addr from the Advertised Neighbor Set; 1570 2. AL_net_addr from each Local Attached Neighbor Tuple, each 1571 associated with a TLV with Type == GATEWAY and Value == 1572 AL_dist. 1574 11.1. TC Message: Transmission 1576 Complete TC messages are generated and transmitted periodically on 1577 all OLSRv2 interfaces, with a default interval between two 1578 consecutive TC transmissions by the same node of TC_INTERVAL. 1580 TC messages MAY be generated in response to a change of contents, 1581 indicated by a change in ANSN. In this case a node MAY send a 1582 complete TC message, and if so MAY re-start its TC message schedule. 1583 Alternatively a node MAY send an incomplete TC message with at least 1584 the new content in its address blocks. Note that a node cannot 1585 report removal of advertised content using an incomplete TC message. 1587 When sending a TC message in response to a change of contents, a node 1588 must respect a minimum interval of TC_MIN_INTERVAL between generated 1589 TC messages. Sending an incomplete TC message MUST NOT cause the 1590 interval between complete TC messages to be increased, and thus a 1591 node MUST NOT send an incomplete TC message if within TC_MIN_INTERVAL 1592 of the next scheduled complete TC message. 1594 The generation of TC messages, whether scheduled or triggered by a 1595 change of contents MAY be jittered as described in [RFC5148]. The 1596 values of MAXJITTER used SHOULD be: 1598 o TP_MAXJITTER for periodic TC message generation; 1600 o TT_MAXJITTER for responsive TC message generation. 1602 TC messages are included in packets as specified in [packetbb]. 1603 These packets MAY contain other messages, including HELLO messages 1604 and TC messages with different originator addresses. TC messages are 1605 forwarded according to the specification in Section 7.4. 1607 12. TC Message Processing 1609 When, according to Section 7.3, a TC message is to be "processed 1610 according to its type", this means that: 1612 o If any address associated with a TLV with Type == LOCAL_IF is one 1613 of the receiving node's current or recently used interface 1614 addresses (i.e. is in any I_local_iface_addr_list in the Local 1615 Interface Set or is equal to any IR_local_iface_addr in the 1616 Removed Interface Address Set), then the TC message MUST be 1617 discarded. 1619 o If the TC message does not contain exactly one message TLV with 1620 Type == CONT_SEQ_NUM and Type Extension == COMPLETE or Type 1621 Extension == INCOMPLETE, then the TC message MUST be discarded. 1623 o If the TC message contains a message TLV with Type == CONT_SEQ_NUM 1624 and Type Extension == COMPLETE, then processing according to 1625 Section 12.1 and then according to Section 12.2 is carried out. 1627 o If the TC message contains a message TLV with Type == CONT_SEQ_NUM 1628 and Type Extension == INCOMPLETE, then only processing according 1629 to Section 12.1 is carried out. 1631 12.1. Initial TC Message Processing 1633 For the purposes of this section: 1635 o "originator address" refers to the originator address in the TC 1636 message header. 1638 o "validity time" is calculated from the VALIDITY_TIME message TLV 1639 in the TC message according to the specification in [timetlv]. 1640 All information in the TC message has the same validity time. 1642 o "ANSN" is defined as being the value of the message TLV with Type 1643 == CONT_SEQ_NUM. 1645 o "sending address list" refers to the list of addresses in all 1646 address blocks which have associated TLV(s) with Type == LOCAL_IF 1647 and Value == UNSPEC_IF. If the sending address list is otherwise 1648 empty, then the message's originator address is added to the 1649 sending address list, with maximum prefix length. 1651 o Comparisons of sequence numbers are carried out as specified in 1652 Section 18. 1654 The TC message is processed as follows: 1656 1. The Advertising Remote Node Set is updated according to 1657 Section 12.1.1; if the TC message is indicated as discarded in 1658 that processing then the following steps are not carried out. 1660 2. The Topology Set is updated according to Section 12.1.2. 1662 3. The Attached Network Set is updated according to Section 12.1.3. 1664 12.1.1. Populating the Advertising Remote Node Set 1666 The node MUST update its Advertising Remote Node Set as follows: 1668 1. If there is an Advertising Remote Node Tuple with: 1670 * AR_orig_addr == originator address; AND 1672 * AR_seq_number > ANSN 1674 then the TC message MUST be discarded. 1676 2. Otherwise: 1678 1. If there is no Advertising Remote Node Tuple such that: 1680 + AR_orig_addr == originator address; 1682 then create an Advertising Remote Node Tuple with: 1684 + AR_orig_addr = originator address. 1686 2. This Advertising Remote Node Tuple (existing or new, the 1687 "current tuple") is then modified as follows: 1689 + AR_seq_number = ANSN; 1691 + AR_time = current time + validity time. 1693 + AR_iface_addr_list = sending address list 1695 3. For each other Advertising Remote Node Tuple (with a 1696 different AR_orig_addr, the "other tuple") whose 1697 AR_iface_addr_list contains any address in the 1698 AR_iface_addr_list of the current tuple: 1700 1. remove all Topology Tuples with T_orig_addr == 1701 AR_orig_addr of the other tuple; 1703 2. remove all Attached Network Tuples with AN_orig_addr == 1704 AR_orig_addr of the other tuple; 1706 3. remove the other tuple. 1708 12.1.2. Populating the Topology Set 1710 The node MUST update its Topology Set as follows: 1712 1. For each address (henceforth advertised address) in an address 1713 block which does not have an associated TLV with Type == 1714 LOCAL_IF, or an associated TLV with Type == GATEWAY: 1716 1. If there is no Topology Tuple such that: 1718 + T_dest_iface_addr == advertised address; AND 1720 + T_orig_addr == originator address 1722 then create a new Topology Tuple with: 1724 + T_dest_iface_addr = advertised address; 1726 + T_orig_addr = originator address. 1728 2. This Topology Tuple (existing or new) is then modified as 1729 follows: 1731 + T_seq_number = ANSN; 1733 + T_time = current time + validity time. 1735 12.1.3. Populating the Attached Network Set 1737 The node MUST update its Attached Network Set as follows: 1739 1. For each address (henceforth network address) in an address block 1740 which does not have an associated TLV with Type == LOCAL_IF, and 1741 does have an associated TLV with Type == GATEWAY: 1743 1. If there is no Attached Network Tuple such that: 1745 + AN_net_addr == network address; AND 1747 + AN_orig_addr == originator address 1749 then create a new Attached Network Tuple with: 1751 + AN_net_addr = network address; 1753 + AN_orig_addr = originator address 1755 2. This Attached Network Tuple (existing or new) is then 1756 modified as follows: 1758 + AN_dist = the value of the associated GATEWAY TLV; 1760 + AN_seq_number = ANSN; 1762 + AN_time = current time + validity time. 1764 12.2. Completing TC Message Processing 1766 The TC message is processed as follows: 1768 1. The Topology Set is updated according to Section 12.2.1. 1770 2. The Attached Network Set is updated according to Section 12.2.2. 1772 12.2.1. Purging the Topology Set 1774 The Topology Set MUST be updated as follows: 1776 1. Any Topology Tuples with: 1778 * T_orig_addr == originator address; AND 1780 * T_seq_number < ANSN 1782 MUST be removed. 1784 12.2.2. Purging the Attached Network Set 1786 The Attached Network Set MUST be updated as follows: 1788 1. Any Attached Network Tuples with: 1790 * AN_orig_addr == originator address; AND 1792 * AN_seq_number < ANSN 1794 MUST be removed. 1796 13. Information Base Changes 1798 1. The Originator Set in the Local Information Base MUST be updated 1799 when the node changes originator address. If there is no 1800 Originator Tuple with: 1802 * O_orig_addr == old originator address 1804 then create an Originator Tuple with: 1806 * O_orig_addr = old originator address 1808 This Originator Tuple (existing or new) is then modified as 1809 follows: 1811 * O_time = current time + O_HOLD_TIME 1813 2. The Topology Information Base MUST be changed when an Advertising 1814 Remote Node Tuple expires (AR_time is reached). The following 1815 changes are required before the Advertising Remote Node Tuple is 1816 removed: 1818 1. All Topology Tuples with: 1820 + T_orig_addr == AR_orig_addr of the Advertising Remote Node 1821 Tuple 1823 are removed. 1825 2. All Attached Network Tuples with: 1827 + AN_orig_addr == AR_orig_addr of the Advertising Remote 1828 Node Tuple 1830 are removed. 1832 14. Selecting MPRs 1834 Each node MUST select, from among its willing symmetric 1-hop 1835 neighbors, a subset of nodes as MPRs. MPRs are used to flood control 1836 messages from a node into the network, while reducing the number of 1837 retransmissions that will occur in a region. Thus, the concept of 1838 MPR flooding is an optimization of a classical flooding mechanism. 1839 MPRs MAY also be used to reduce the shared topology information in 1840 the network. Consequently, while it is not essential that the set of 1841 MPRs is minimal, keeping the number of MPRs small ensures that the 1842 overhead of OLSRv2 is kept at a minimum. 1844 A node MUST select MPRs for each of its OLSRv2 interfaces, but then 1845 forms the union of those sets as its single set of MPRs. This union 1846 MUST include all symmetric 1-hop neighbors with willingness 1847 WILL_ALWAYS. Only this overall set of MPRs is relevant, the recorded 1848 and used MPR relationship is one of nodes, not interfaces. Nodes MAY 1849 select their MPRs by any process which satisfies the conditions which 1850 follow. Nodes can freely interoperate whether they use the same or 1851 different MPR selection algorithms. 1853 For each OLSRv2 interface a node MUST select a set of MPRs. This set 1854 MUST have the properties that: 1856 o All of the selected MPRs are willing symmetric 1-hop neighbors, 1857 AND; 1859 o If the selecting node sends a message on that OLSRv2 interface, 1860 and that message is successfully forwarded by all of the selected 1861 MPRs for that interface, then all symmetric strict 2-hop neighbors 1862 of the selecting node through that OLSRv2 interface will receive 1863 that message on a symmetric link. 1865 Note that it is always possible to select a valid set of MPRs. The 1866 set of all willing symmetric 1-hop neighbors of a node is a (maximal) 1867 valid set of MPRs for that node. However a node SHOULD NOT select a 1868 symmetric 1-hop neighbor with willingness not equal to WILL_ALWAYS as 1869 an MPR if there are no symmetric strict 2-hop neighbors with a 1870 symmetric link to that symmetric 1-hop neighbor. Thus a node with no 1871 symmetric 1-hop neighbors with willingness WILL_ALWAYS and with no 1872 symmetric strict 2-hop neighbors SHOULD NOT select any MPRs. 1874 A node MAY select its MPRs for each OLSRv2 interface independently, 1875 or it MAY coordinate its MPR selections across its OLSRv2 interfaces, 1876 as long as the required condition is satisfied for each OLSRv2 1877 interface. Each node MAY select its MPRs independently from the MPR 1878 selection by other nodes, or it MAY, for example, give preference to 1879 nodes that either are, or are not, already selected as MPRs by other 1880 nodes. 1882 When selecting MPRs for each OLSRv2 interface independently, this MAY 1883 be done using information from the Link Set and 2-Hop Set of that 1884 OLSRv2 interface, and the Neighbor Set of the node (specifically the 1885 N_willingness elements). 1887 The selection of MPRs (overall, not per OLSRv2 interface) is recorded 1888 in the Neighbor Set of the node (using the N_mpr elements). A 1889 selected MPR MUST be a willing symmetric 1-hop neighbor (i.e. the 1890 corresponding N_symmetric == true, and the corresponding 1891 N_willingness is not equal to WILL_NEVER). 1893 A node MUST recalculate its MPRs whenever the currently selected set 1894 of MPRs does not still satisfy the required conditions. It MAY 1895 recalculate its MPRs if the current set of MPRs is still valid, but 1896 could be more efficient. It is sufficient to recalculate a node's 1897 MPRs when there is a change to any of the node's Link Sets affecting 1898 the symmetry of any link (addition or removal of a Link Tuple with 1899 L_status == SYMMETRIC, or change of any L_status to or from 1900 SYMMETRIC), any change to any of the node's 2-Hop Sets, or a change 1901 of the N_willingness (to or from WILL_NEVER or to WILL_ALWAYS is 1902 sufficient) of any Neighbor Tuple with N_symmetric == true. 1904 An algorithm that creates a set of MPRs that satisfies the required 1905 conditions is given in Appendix B. 1907 15. Populating Derived Sets 1909 The Relay Sets and the Advertised Neighbor Set of a node are denoted 1910 derived sets, since updates to these sets are not directly a function 1911 of message exchanges, but rather are derived from updates to other 1912 sets, in particular to the MPR selector status of other nodes 1913 recorded in the Neighbor Set. 1915 15.1. Populating the Relay Set 1917 The Relay Set for an OLSRv2 interface contains the set of OLSRv2 1918 interface addresses of those symmetric 1-hop neighbors for which this 1919 OLSRv2 interface is to relay broadcast traffic. This set MUST 1920 contain only addresses of OLSRv2 interfaces with which this OLSRv2 1921 interface has a symmetric link. This set MUST include all such 1922 addresses of all such OLSRv2 interfaces of nodes which are MPR 1923 selectors of this node. 1925 The Relay Set for an OLSRv2 interface of this node is thus created 1926 by: 1928 1. For each Link Tuple in the Link Set for this OLSRv2 interface 1929 with L_status == SYMMETRIC, and the corresponding Neighbor Tuple 1930 with N_neighbor_iface_addr_list containing 1931 L_neighbor_iface_addr_list: 1933 1. All addresses from L_neighbor_iface_addr_list MUST be 1934 included in the Relay Set of this OLSRv2 interface if 1935 N_mpr_selector == true, and otherwise MAY be so included. 1937 15.2. Populating the Advertised Neighbor Set 1939 The Advertised Neighbor Set of a node contains all interface 1940 addresses of those symmetric 1-hop neighbors to which the node 1941 advertises a link in its TC messages. This set MUST include all 1942 addresses in all MPR selector of this node. 1944 The Advertised Neighbor Set for this node is thus created by: 1946 1. For each Neighbor Tuple with N_symmetric == true: 1948 1. All addresses from N_neighbor_iface_addr_list MUST be 1949 included in the Advertised Neighbor Set if N_mpr_selector == 1950 true, and otherwise MAY be so included. 1952 Whenever address(es) are added to or removed from the Advertised 1953 Neighbor Set, its ANSN MUST be incremented. 1955 16. Routing Set Calculation 1957 The Routing Set of a node is populated with Routing Tuples that 1958 represent paths from that node to all destinations in the network. 1959 These paths are calculated based on the Network Topology Graph, which 1960 is constructed from information in the Information Bases, obtained 1961 via HELLO and TC message exchange. 1963 16.1. Network Topology Graph 1965 The Network Topology Graph is formed from information from the node's 1966 Link Sets, Neighbor Set, Topology Set and Attached Network Set. The 1967 Network Topology Graph SHOULD also use information from the node's 1968 2-Hop Sets. The Network Topology Graph forms that node's topological 1969 view of the network in form of a directed graph, containing the 1970 following arcs: 1972 o Local symmetric links - all arcs X -> Y such that: 1974 * X is an address in the I_local_iface_addr_list of a Local 1975 Interface Tuple of this node, AND; 1977 * Y is an address in the L_neighbor_iface_addr_list of a Link 1978 Tuple in the corresponding (to the OLSRv2 interface of that 1979 I_local_iface_addr_list) Link Set which has L_status == 1980 SYMMETRIC. 1982 o 2-hop symmetric links - all arcs Y -> Z such that: 1984 * Y is an address in the L_neighbor_iface_addr_list of a Link 1985 Tuple, in any of the node's Link Sets, which has L_status == 1986 SYMMETRIC, AND; 1988 * the Neighbor Tuple with Y in its N_neighbor_iface_addr_list has 1989 N_willingness not equal to WILL_NEVER, AND; 1991 * Z is the N2_2hop_iface_addr of a 2-Hop Tuple in the 2-Hop Set 1992 corresponding to the OLSRv2 interface of the chosen Link Set. 1994 o Advertised symmetric links - all arcs U -> V such that there 1995 exists a Topology Tuple and a corresponding Advertising Remote 1996 Node Tuple (i.e. with AR_orig_addr == T_orig_addr) with: 1998 * U is in the AR_iface_addr_list of the Advertising Remote Node 1999 Tuple, AND; 2001 * V is the T_dest_iface_addr of the Topology Tuple. 2003 o Symmetric 1-hop neighbor addresses - all arcs Y -> W such that: 2005 * Y is, and W is not, an address in the 2006 L_neighbor_iface_addr_list of a Link Tuple, in any of the 2007 node's Link Sets, which has L_status == SYMMETRIC, AND; 2009 * W and Y are included in the same N_neighbor_iface_addr_list 2010 (i.e. the one in the Neighbor Tuple whose 2011 N_neighbor_iface_addr_list contains the 2012 L_neighbor_iface_addr_list that includes Y). 2014 o Attached network addresses - all arcs U -> T such that there 2015 exists an Attached Network Tuple and a corresponding Advertising 2016 Remote Node Tuple (i.e. with AR_orig_addr == AN_orig_addr) with: 2018 * U is in the AR_iface_addr_list of the Advertising Remote Node 2019 Tuple, AND; 2021 * T is the AN_net_addr of the Attached Network Tuple. 2023 All links in the first three cases above have a hop count of one, the 2024 symmetric 1-hop neighbor addresses have a hop count of zero, and the 2025 attached network addresses have a hop count given by the appropriate 2026 value of AN_dist. 2028 16.2. Populating the Routing Set 2030 The Routing Set MUST contain the shortest paths for all destinations 2031 from all local OLSRv2 interfaces using the Network Topology Graph. 2032 This calculation MAY use any algorithm, including any means of 2033 choosing between paths of equal length. 2035 Using the notation of Section 16.1, each path will have as its first 2036 arc a local symmetric link X -> Y. There will be a path for each 2037 terminating Y, Z, V, W and T which can be connected to local OLSRv2 2038 interface address X using the indicated arcs. The corresponding 2039 Routing Tuple for this path will have: 2041 o R_dest_addr = the terminating Y, Z, V, W or T; 2043 o R_next_iface_addr = the first arc's Y; 2045 o R_dist = the total hop count of the path; 2047 o R_local_iface_addr = the first arc's X. 2049 An example algorithm for calculating the Routing Set of a node is 2050 given in Appendix C. 2052 16.3. Routing Set Updates 2054 The Routing Set MUST be updated when changes in the Neighborhood 2055 Information Base or the Topology Information Base indicate a change 2056 of the known symmetric links and/or attached networks in the MANET. 2057 It is sufficient to consider only changes which affect at least one 2058 of: 2060 o The Link Set of any OLSRv2 interface, and to consider only Link 2061 Tuples which have, or just had, L_status == SYMMETRIC (including 2062 removal of such Link Tuples). 2064 o The Neighbor Set of the node, and to consider only Neighbor Tuples 2065 that have, or just had, N_symmetric == true. 2067 o The 2-Hop Set of any OLSRv2 interface. 2069 o The Advertising Remote Node Set of the node. 2071 o The Topology Set of the node. 2073 o The Attached Network Set of the node. 2075 Updates to the Routing Set do not generate or trigger any messages to 2076 be transmitted. The state of the Routing Set SHOULD, however, be 2077 reflected in the IP routing table by adding and removing entries from 2078 the IP routing table as appropriate. 2080 17. Proposed Values for Parameters and Constants 2082 OLSRv2 uses all parameters and constants defined in [nhdp] and 2083 additional parameters and constants defined in this document. All 2084 but one (RX_HOLD_TIME) of these additional parameters are node 2085 parameters as defined in [nhdp]. These proposed values of the 2086 additional parameters are appropriate to the case where all 2087 parameters (including those defined in [nhdp]) have a single value. 2088 Proposed values for parameters defined in [nhdp] are given in that 2089 document. 2091 17.1. Local History Time Parameters 2093 o O_HOLD_TIME = 30 seconds 2095 17.2. Message Interval Parameters 2097 o TC_INTERVAL = 5 seconds 2099 o TC_MIN_INTERVAL = TC_INTERVAL/4 2101 17.3. Advertised Information Validity Time Parameters 2103 o T_HOLD_TIME = 3 x TC_INTERVAL 2105 o A_HOLD_TIME = T_HOLD_TIME 2107 17.4. Received Message Validity Time Parameters 2109 o RX_HOLD_TIME = 30 seconds 2111 o P_HOLD_TIME = 30 seconds 2113 o F_HOLD_TIME = 30 seconds 2115 17.5. Jitter Time Parameters 2117 o TP_MAXJITTER = HP_MAXJITTER 2119 o TT_MAXJITTER = HT_MAXJITTER 2121 o F_MAXJITTER = TT_MAXJITTER 2123 17.6. Hop Limit Parameter 2125 o TC_HOP_LIMIT = 255 2127 17.7. Willingness Parameter and Constants 2129 o WILLINGNESS = WILL_DEFAULT 2131 o WILL_NEVER = 0 2133 o WILL_DEFAULT = 3 2135 o WILL_ALWAYS = 7 2137 18. Sequence Numbers 2139 Sequence numbers are used in OLSRv2 with the purpose of discarding 2140 "old" information, i.e. messages received out of order. However with 2141 a limited number of bits for representing sequence numbers, wrap- 2142 around (that the sequence number is incremented from the maximum 2143 possible value to zero) will occur. To prevent this from interfering 2144 with the operation of OLSRv2, the following MUST be observed when 2145 determining the ordering of sequence numbers. 2147 The term MAXVALUE designates in the following one more than the 2148 largest possible value for a sequence number. For a 16 bit sequence 2149 number (as are those defined in this specification) MAXVALUE is 2150 65536. 2152 The sequence number S1 is said to be "greater than" the sequence 2153 number S2 if: 2155 o S1 > S2 AND S1 - S2 < MAXVALUE/2 OR 2157 o S2 > S1 AND S2 - S1 > MAXVALUE/2 2159 When sequence numbers S1 and S2 differ by MAXVALUE/2 their ordering 2160 cannot be determined. In this case, which should not occur, either 2161 ordering may be assumed. 2163 Thus when comparing two messages, it is possible - even in the 2164 presence of wrap-around - to determine which message contains the 2165 most recent information. 2167 19. Security Considerations 2169 Currently, OLSRv2 does not specify any special security measures. As 2170 a proactive routing protocol, OLSRv2 makes a target for various 2171 attacks. The various possible vulnerabilities are discussed in this 2172 section. 2174 19.1. Confidentiality 2176 Being a proactive protocol, OLSRv2 periodically MPR floods 2177 topological information to all nodes in the network. Hence, if used 2178 in an unprotected wireless network, the network topology is revealed 2179 to anyone who listens to OLSRv2 control messages. 2181 In situations where the confidentiality of the network topology is of 2182 importance, regular cryptographic techniques, such as exchange of 2183 OLSRv2 control traffic messages encrypted by PGP [RFC4880] or 2184 encrypted by some shared secret key, can be applied to ensure that 2185 control traffic can be read and interpreted by only those authorized 2186 to do so. 2188 19.2. Integrity 2190 In OLSRv2, each node is injecting topological information into the 2191 network through transmitting HELLO messages and, for some nodes, TC 2192 messages. If some nodes for some reason, malicious or malfunction, 2193 inject invalid control traffic, network integrity may be compromised. 2194 Therefore, message authentication is recommended. 2196 Different such situations may occur, for instance: 2198 1. a node generates TC messages, advertising links to non-neighbor 2199 nodes; 2201 2. a node generates TC messages, pretending to be another node; 2203 3. a node generates HELLO messages, advertising non-neighbor nodes; 2205 4. a node generates HELLO messages, pretending to be another node; 2207 5. a node forwards altered control messages; 2209 6. a node does not forward control messages; 2211 7. a node does not select multipoint relays correctly; 2213 8. a node forwards broadcast control messages unaltered, but does 2214 not forward unicast data traffic; 2216 9. a node "replays" previously recorded control traffic from another 2217 node. 2219 Authentication of the originator node for control messages (for 2220 situations 2, 4 and 5) and on the individual links announced in the 2221 control messages (for situations 1 and 3) may be used as a 2222 countermeasure. However to prevent nodes from repeating old (and 2223 correctly authenticated) information (situation 9) temporal 2224 information is required, allowing a node to positively identify such 2225 delayed messages. 2227 In general, digital signatures and other required security 2228 information may be transmitted as a separate OLSRv2 message type, or 2229 signatures and security information may be transmitted within the 2230 OLSRv2 HELLO and TC messages, using the TLV mechanism. Either option 2231 permits that "secured" and "unsecured" nodes can coexist in the same 2232 network, if desired, 2234 Specifically, the authenticity of entire OLSRv2 control packets can 2235 be established through employing IPsec authentication headers, 2236 whereas authenticity of individual links (situations 1 and 3) require 2237 additional security information to be distributed. 2239 An important consideration is that all control messages in OLSRv2 are 2240 transmitted either to all nodes in the neighborhood (HELLO messages) 2241 or broadcast to all nodes in the network (TC messages). 2243 For example, a control message in OLSRv2 is always a point-to- 2244 multipoint transmission. It is therefore important that the 2245 authentication mechanism employed permits that any receiving node can 2246 validate the authenticity of a message. As an analogy, given a block 2247 of text, signed by a PGP private key, then anyone with the 2248 corresponding public key can verify the authenticity of the text. 2250 19.3. Interaction with External Routing Domains 2252 OLSRv2 does, through the use of TC messages, provide a basic 2253 mechanism for injecting external routing information to the OLSRv2 2254 domain. Appendix A also specifies that routing information can be 2255 extracted from the topology table or the routing table of OLSRv2 and, 2256 potentially, injected into an external domain if the routing protocol 2257 governing that domain permits. 2259 Other than as described in Appendix A, when operating nodes 2260 connecting OLSRv2 to an external routing domain, care MUST be taken 2261 not to allow potentially insecure and untrustworthy information to be 2262 injected from the OLSRv2 domain to external routing domains. Care 2263 MUST be taken to validate the correctness of information prior to it 2264 being injected as to avoid polluting routing tables with invalid 2265 information. 2267 A recommended way of extending connectivity from an existing routing 2268 domain to an OLSRv2 routed MANET is to assign an IP prefix (under the 2269 authority of the nodes/gateways connecting the MANET with the exiting 2270 routing domain) exclusively to the OLSRv2 MANET area, and to 2271 configure the gateways statically to advertise routes to that IP 2272 sequence to nodes in the existing routing domain. 2274 20. IANA Considerations 2276 20.1. Message Types 2278 This specification defines one message type, to be allocated from the 2279 0-223 range of the "Message Types" namespace defined in [packetbb], 2280 as specified in Table 5. 2282 +------+------+-----------------------------------------+ 2283 | Name | Type | Description | 2284 +------+------+-----------------------------------------+ 2285 | TC | TBD1 | Topology Control (MANET-wide signaling) | 2286 +------+------+-----------------------------------------+ 2288 Table 5 2290 20.2. Message TLV Types 2292 This specification defines two message TLV types, which must be 2293 allocated from the "Message TLV Types" namespace defined in 2294 [packetbb]. IANA are requested to make allocations in the 8-127 2295 range for these types. This will create two new type extension 2296 registries with assignments as specified in Table 6 and Table 7. 2297 Specifications of these TLVs are in Section 8.1.1 and Section 8.2.1. 2299 +-------------+------+-----------+----------------------------------+ 2300 | Name | Type | Type | Description | 2301 | | | extension | | 2302 +-------------+------+-----------+----------------------------------+ 2303 | MPR_WILLING | TBD2 | 0 | Specifies the originating node's | 2304 | | | | willingness to act as a relay | 2305 | | | | and to partake in network | 2306 | | | | formation | 2307 | | | | | 2308 | | | 1-255 | Expert Review | 2309 +-------------+------+-----------+----------------------------------+ 2311 Table 6 2313 +--------------+------+----------------+----------------------------+ 2314 | Name | Type | Type extension | Description | 2315 +--------------+------+----------------+----------------------------+ 2316 | CONT_SEQ_NUM | TBD3 | 0 (COMPLETE) | Specifies a content | 2317 | | | | sequence number for this | 2318 | | | | complete message | 2319 | | | | | 2320 | | | 1 (INCOMPLETE) | Specifies a content | 2321 | | | | sequence number for this | 2322 | | | | incomplete message | 2323 | | | | | 2324 | | | 2-255 | Expert Review | 2325 +--------------+------+----------------+----------------------------+ 2327 Table 7 2329 Type extensions indicated as Expert Review SHOULD be allocated as 2330 described in [packetbb], based on Expert Review as defined in 2331 [RFC5226]. 2333 20.3. Address Block TLV Types 2335 This specification defines two address block TLV types, which must be 2336 allocated from the "Address Block TLV Types" namespace defined in 2337 [packetbb]. IANA are requested to make allocations in the 8-127 2338 range for these types. This will create two new type extension 2339 registries with assignments as specified in Table 8 and Table 9. 2340 Specifications of these TLVs are in Section 8.1.2 and Section 8.2.2. 2342 +------+------+-----------+-----------------------------------------+ 2343 | Name | Type | Type | Description | 2344 | | | extension | | 2345 +------+------+-----------+-----------------------------------------+ 2346 | MPR | TBD4 | 0 | Specifies that a given address is of a | 2347 | | | | node selected as an MPR | 2348 | | | | | 2349 | | | 1-255 | Expert Review | 2350 +------+------+-----------+-----------------------------------------+ 2352 Table 8 2354 +---------+------+-----------+--------------------------------------+ 2355 | Name | Type | Type | Description | 2356 | | | extension | | 2357 +---------+------+-----------+--------------------------------------+ 2358 | GATEWAY | TBD5 | 0 | Specifies that a given address is | 2359 | | | | reached via a gateway on the | 2360 | | | | originating node | 2361 | | | | | 2362 | | | 1-255 | Expert Review | 2363 +---------+------+-----------+--------------------------------------+ 2365 Table 9 2367 Type extensions indicated as Expert Review SHOULD be allocated as 2368 described in [packetbb], based on Expert Review as defined in 2369 [RFC5226]. 2371 21. References 2373 21.1. Normative References 2375 [packetbb] Clausen, T., Dean, J., Dearlove, C., and C. Adjih, 2376 "Generalized MANET Packet/Message Format", work in 2377 progress draft-ietf-manet-packetbb-13.txt, June 2008. 2379 [timetlv] Clausen, T. and C. Dearlove, "Representing multi-value 2380 time in MANETs", Work In 2381 Progress draft-ietf-manet-timetlv-05.txt, July 2008. 2383 [RFC5148] Clausen, T., Dearlove, C., and B. Adamson, "Jitter 2384 considerations in MANETs", RFC 5148, February 2008. 2386 [nhdp] Clausen, T., Dean, J., and C. Dearlove, "MANET 2387 Neighborhood Discovery Protocol (NHDP)", work in 2388 progress draft-ietf-manet-nhdp-07.txt, July 2008. 2390 [manet-iana] Chakeres, I., "IANA Allocations for MANET Protocols", 2391 Work In Progress draft-ietf-manet-iana-07.txt, 2392 November 2007. 2394 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 2395 Requirement Levels", RFC 2119, BCP 14, March 1997. 2397 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing 2398 an IANA Considerations Section in RFCs", RFC 5226, 2399 BCP 26, May 2008. 2401 21.2. Informative References 2403 [RFC2501] Macker, J. and S. Corson, "Mobile Ad hoc Networking 2404 (MANET): Routing Protocol Performance Issues and 2405 Evaluation Considerations", RFC 2501, January 1999. 2407 [RFC3626] Clausen, T. and P. Jacquet, "The Optimized Link State 2408 Routing Protocol", RFC 3626, October 2003. 2410 [RFC4880] Callas, J., Donnerhacke, L., Finney, H., and R. Thayer, 2411 "OpenPGP message format", RFC 4880, November 2007. 2413 [HIPERLAN] ETSI, "ETSI STC-RES10 Committee. Radio equipment and 2414 systems: HIPERLAN type 1, functional specifications ETS 2415 300-652", June 1996. 2417 [HIPERLAN2] Jacquet, P., Minet, P., Muhlethaler, P., and N. 2418 Rivierre, "Increasing reliability in cable free radio 2419 LANs: Low level forwarding in HIPERLAN.", 1996. 2421 [MPR] Qayyum, A., Viennot, L., and A. Laouiti, "Multipoint 2422 relaying: An efficient technique for flooding in mobile 2423 wireless networks.", 2001. 2425 [FSR] Pei, G., Gerla, M., and T. Chen, "Fisheye state routing 2426 in mobile ad hoc networks", 2000. 2428 [FSLS] Santivanez, C., Ramanathan, R., and I. Stavrakakis, 2429 "Making link-state routing scale for ad hoc networks", 2430 2000. 2432 Appendix A. Node Configuration 2434 OLSRv2 does not make any assumption about node addresses, other than 2435 that each node is assumed to have at least one unique and routable IP 2436 address for each interface that it has which participates in the 2437 MANET. 2439 When applicable, a recommended way of connecting an OLSRv2 network to 2440 an existing IP routing domain is to assign an IP prefix (under the 2441 authority of the nodes/gateways connecting the MANET with the routing 2442 domain) exclusively to the OLSRv2 area, and to configure the gateways 2443 statically to advertise routes to that IP sequence to nodes in the 2444 existing routing domain. 2446 Appendix B. Example Algorithm for Calculating MPRs 2448 The following specifies an algorithm which MAY be used to select 2449 MPRs. MPRs are calculated per OLSRv2 interface, but then a single 2450 set of MPRs is formed from the union of the MPRs for all OLSRv2 2451 interfaces. (As noted in Section 14 a node MAY improve on this, by 2452 coordination between OLSRv2 interfaces.) A node's MPRs are recorded 2453 using the element N_mpr in Neighbor Tuples. 2455 If using this algorithm then the following steps MUST be executed in 2456 order for a node to select its MPRs: 2458 1. Set N_mpr = false in all Neighbor Tuples; 2460 2. For each Neighbor Tuple with N_symmetric == true and 2461 N_willingness == WILL_ALWAYS, set N_mpr = true; 2463 3. For each OLSRv2 interface of the node, use the algorithm in 2464 Appendix B.2. Note that this sets N_mpr = true for some Neighbor 2465 Tuples, these nodes are already selected as MPRs when using the 2466 algorithm for following OLSRv2 interfaces. 2468 4. OPTIONALLY, consider each selected MPR in turn, and if the set of 2469 selected MPRs without that node still satisfies the necessary 2470 conditions, for all OLSRv2 interfaces, then that node MAY be 2471 removed from the set of MPRs. This process MAY be repeated until 2472 no MPRs are removed. Nodes MAY be considered in order of 2473 increasing N_willingness. 2475 Symmetric 1-hop neighbor nodes with N_willingness == WILL_NEVER MUST 2476 NOT be selected as MPRs, and MUST be ignored in the following 2477 algorithm, as MUST be symmetric 2-hop neighbor nodes which are also 2478 symmetric 1-hop neighbor nodes (i.e. when considering 2-Hop Tuples, 2479 ignore any 2-Hop Tuples whose N2_2hop_iface_addr is in the 2480 N_neighbor_iface_addr_list of any Neighbor Tuple, or whose 2481 N2_neighbor_iface_addr_list is included in the 2482 N_neighbor_iface_addr_list of any Neighbor Tuple with N_willingness 2483 == WILL_NEVER). 2485 B.1. Terminology 2487 The following terminology will be used when selecting MPRs for the 2488 OLSRv2 interface I: 2490 N(I) - The set of symmetric 1-hop neighbors which have a symmetric 2491 link to I. 2493 N2(I) - The set of addresses of interfaces of a node with a 2494 symmetric link to a node in N(I); this MAY be restricted to 2495 considering only information received over I (in which case N2(I) 2496 is the set of N2_2hop_iface_addr in 2-Hop Tuples in the 2-Hop Set 2497 for OLSRv2 interface I). 2499 Connected to I via Y - An address A in N2(I) is connected to I via a 2500 node Y in N(I) if A is an address of an interface of a symmetric 2501 1-hop neighbor of Y (i.e. A is the N2_2hop_iface_addr in a 2-Hop 2502 Tuple in the 2-Hop Set for OLSRv2 interface I, and whose 2503 N2_neighbor_iface_addr_list is contained in the set of interface 2504 addresses of Y). 2506 D(Y, I) - For a node Y in N(I), the number of addresses in N2(I) 2507 which are connected to I via Y. 2509 R(Y, I): - For a node Y in N(I), the number of addresses in N2(I) 2510 which are connected to I via Y, but are not connected to I via any 2511 node which has already been selected as an MPR. 2513 B.2. MPR Selection Algorithm for each OLSRv2 Interface 2515 When selecting MPRs for the OLSRv2 interface I: 2517 1. For each address A in N2(I) for which there is only one node Y in 2518 N(I) such that A is connected to I via Y, select that node Y as 2519 an MPR (i.e. set N_mpr = true in the Neighbor Tuple corresponding 2520 to Y). 2522 2. While there exists any node Y in N(I) with R(Y, I) > 0: 2524 1. Select a node Y in N(I) with R(Y, I) > 0 in the following 2525 order of priority: 2527 + greatest N_willingness in the Neighbor Tuple corresponding 2528 to Y, THEN; 2530 + greatest R(Y, I), THEN; 2532 + greatest D(Y, I), THEN; 2534 + N_mpr_selector is equal to true, if possible, THEN; 2536 + any choice. 2538 2. Select Y as an MPR (i.e. set N_mpr = true in the Neighbor 2539 Tuple corresponding to Y). 2541 Appendix C. Example Algorithm for Calculating the Routing Set 2543 The following procedure is given as an example for calculating the 2544 Routing Set using a variation of Dijkstra's algorithm. First all 2545 Routing Tuples are removed, and then the procedures in the following 2546 sections are applied in turn. 2548 C.1. Add Local Symmetric Links 2550 1. For each Local Interface Tuple in the Local Interface Set: 2552 1. For each address A in I_local_iface_addr_list: 2554 1. For each Link Tuple in the Link Set for this local 2555 interface, with L_status == SYMMETRIC: 2557 1. For each address, B, in that Link Tuple's 2558 L_neighbor_iface_addr_list, add a new Routing Tuple 2559 with: 2561 o R_dest_addr = B; 2563 o R_next_iface_addr = B; 2565 o R_dist = 1; 2567 o R_local_iface_addr = A. 2569 2. For each Neighbor Tuple, for which there is an address B in 2570 N_neighbor_iface_addr_list, for which there is a Routing Tuple 2571 (the "previous Routing Tuple") with R_dest_addr == B: 2573 1. For each address C in N_neighbor_iface_addr_list for which 2574 there is no Routing Tuple with R_dest_addr == C, add a 2575 Routing Tuple with: 2577 + R_dest_addr = C; 2579 + R_next_iface_addr = B; 2581 + R_dist = 1; 2583 + R_local_iface_addr = R_local_iface_addr of the previous 2584 Routing Tuple. 2586 C.2. Add Remote Symmetric Links 2588 The following procedure, which adds Routing Tuples for destination 2589 nodes h+1 hops away, MUST be executed for each value of h, starting 2590 with h = 1 and incrementing by 1 for each iteration. The execution 2591 MUST stop if no new Routing Tuples are added in an iteration. 2593 1. For each Topology Tuple, if: 2595 * T_dest_iface_addr is not equal to R_dest_addr of any Routing 2596 Tuple, AND; 2598 * for the Advertising Remote Node Tuple with AR_orig_addr == 2599 T_orig_addr, there is an address in the AR_iface_addr_list 2600 which is equal to the R_dest_addr of a Routing Tuple (the 2601 "previous Routing Tuple") whose R_dist == h 2603 then add a new Routing Tuple, with: 2605 * R_dest_addr = T_dest_iface_addr; 2607 * R_next_iface_addr = R_next_iface_addr of the previous Routing 2608 Tuple; 2610 * R_dist = h+1; 2612 * R_local_iface_addr = R_local_iface_addr of the previous 2613 Routing Tuple. 2615 More than one Topology Tuple may be usable to select the next hop 2616 R_next_iface_addr for reaching the address R_dest_addr. Ties 2617 should be broken such that nodes with greater willingness are 2618 preferred, and between nodes of equal willingness, MPR selectors 2619 are preferred over non-MPR selectors. 2621 2. After the above iteration has completed, if h == 1, for each 2622 2-Hop Neighbor Tuple where: 2624 * N2_2hop_iface_addr is not equal to R_dest_addr of any Routing 2625 Tuple, AND; 2627 * The Neighbor Tuple whose N_neighbor_iface_addr_list contains 2628 N2_neighbor_iface_addr_list has N_willingness not equal to 2629 WILL_NEVER 2631 select a Routing Tuple (the "previous Routing Tuple") whose 2632 R_dest_addr is contained in N2_neighbor_iface_addr_list, and add 2633 a new Routing Tuple with: 2635 * R_dest_addr = N2_2hop_iface_addr; 2637 * R_next_iface_addr = R_next_iface_addr of the previous Routing 2638 Tuple; 2640 * R_dist = 2; 2642 * R_local_iface_addr = R_local_iface_addr of the previous 2643 Routing Tuple. 2645 More than one 2-Hop Neighbor Tuple may be usable to select the 2646 next hop R_next_iface_addr for reaching the address R_dest_addr. 2647 Ties should be broken such that nodes with greater willingness 2648 are preferred, and between nodes of equal willingness, MPR 2649 selectors are preferred over non-MPR selectors. 2651 C.3. Add Attached Networks 2653 1. For each Attached Network Tuple, if for the Advertising Remote 2654 Node Tuple with AR_orig_addr == AN_orig_addr, there is an address 2655 in the AR_iface_addr_list which is equal to the R_dest_addr of a 2656 Routing Tuple (the "previous Routing Tuple"), then: 2658 1. If there is no Routing Tuple with R_dest_addr == AN_net_addr, 2659 then add a new Routing Tuple with: 2661 + R_dest_addr = AN_net_addr; 2663 + R_next_iface_addr = R_next_iface_addr of the previous 2664 Routing Tuple; 2666 + R_dist = (R_dist of the previous Routing Tuple) + AN_dist; 2668 + R_local_iface_addr = R_local_iface_addr of the previous 2669 Routing Tuple. 2671 2. Otherwise if the Routing Tuple with R_dest_addr == 2672 AN_net_addr (the "current Routing Tuple") has R_dist > 2673 (R_dist of the previous Routing Tuple) + AN_dist, then modify 2674 the current Routing Tuple by: 2676 + R_next_iface_addr = R_next_iface_addr of the previous 2677 Routing Tuple; 2679 + R_dist = (R_dist of the previous Routing Tuple) + AN_dist; 2681 + R_local_iface_addr = R_local_iface_addr of the previous 2682 Routing Tuple. 2684 Appendix D. Example Message Layout 2686 An example TC message, using IPv4 (four octet) addresses, is as 2687 follows. The overall message length is 65 octets. 2689 The message has flags octet value 240, and hence a complete message 2690 header. It has a message TLV block with content length 13 octets 2691 containing three TLVs. The first two TLVs are validity and interval 2692 times for the message. The third TLV is the content sequence number 2693 TLV used to carry the 2 octet ANSN, and (with default type extension 2694 zero, i.e. COMPLETE) indicating that the TC message is complete. 2695 Each TLV uses a TLV with flags octet value 16, indicating that it has 2696 a value, but no type extension or start and stop indexes. The first 2697 two TLVs have a value length of 1 octet, the last has a value length 2698 of 2 octets. 2700 The message has two address blocks. The first address block contains 2701 6 addresses, with flags octet value 128, hence with a head section, 2702 (with length 2 octets) but no tail section, and hence mid sections 2703 with length two octets. The following TLV block (content length 6 2704 octets) contains a single LOCAL_IF TLV (flags octet value 48) 2705 indicating that the first three addresses (indexes 0 to 2) are 2706 associated with the value (length 1 octet) UNSPEC_IF, i.e. they are 2707 the originating node's local interface addresses. The remaining 2708 three addresses have no associated TLV, they are the interface 2709 addresses of advertised neighbors. 2711 The second address block contains 1 address, with flags octet 176 2712 indicating that there is a head section (with length 2 octets), that 2713 the tail section (length 2 octets) consists of zero valued octets 2714 (not included), and that there is a single prefix length, which is 2715 16. The network address is thus Head.0.0/16. The following TLV 2716 block (content length 8 octets) includes one TLV that indicates that 2717 the originating node is a gateway to this network, at a given number 2718 of hops distance (value length 1 octet). The TLV flags octet value 2719 of 16 indicates that no indexes are needed. 2721 0 1 2 3 2722 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2723 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2724 | TC |1 1 1 1 0 0 0 0|0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1| 2725 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2726 | Originator Address | 2727 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2728 | Hop Limit | Hop Count | Message Sequence Number | 2729 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2730 |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1| VALIDITY_TIME |0 0 0 1 0 0 0 0| 2731 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2732 |0 0 0 0 0 0 0 1| Value | INTERVAL_TIME |0 0 0 1 0 0 0 0| 2733 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2734 |0 0 0 0 0 0 0 1| Value | CONT_SEQ_NUM |0 0 0 1 0 0 0 0| 2735 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2736 |0 0 0 0 0 0 1 0| Value (ANSN) |0 0 0 0 0 1 1 0| 2737 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2738 |1 0 0 0 0 0 0 0|0 0 0 0 0 0 1 0| Head | 2739 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2740 | Mid | Mid | 2741 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2742 | Mid | Mid | 2743 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2744 | Mid | Mid | 2745 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2746 |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| LOCAL_IF |0 0 1 1 0 0 0 0| 2747 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2748 |0 0 0 0 0 0 0 0|0 0 0 0 0 0 1 0|0 0 0 0 0 0 0 1| UNSPEC_IF | 2749 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2750 |0 0 0 0 0 0 0 1|1 0 1 1 0 0 0 0|0 0 0 0 0 0 1 0| Head | 2751 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2752 | Head (cont) |0 0 0 0 0 0 1 0|0 0 0 1 0 0 0 0|0 0 0 0 0 0 0 0| 2753 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2754 |0 0 0 0 0 1 0 0| GATEWAY |0 0 0 1 0 0 0 0|0 0 0 0 0 0 0 1| 2755 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2756 | Number Hops | 2757 +-+-+-+-+-+-+-+-+ 2759 Appendix E. Constraints 2761 Any process which updates the Local Information Base, the 2762 Neighborhood Information Base or the Topology Information Base MUST 2763 ensure that all constraints specified in this appendix are 2764 maintained, as well as those specified in [nhdp]. 2766 In each Originator Tuple: 2768 o O_orig_addr MUST NOT equal any other O_orig_addr. 2770 o O_orig_addr MUST NOT equal this node's originator address. 2772 In each Local Attached Network Tuple: 2774 o AL_net_addr MUST NOT equal any other AL_net_addr. 2776 o AL_net_addr MUST NOT be in the I_local_iface_addr_list of any 2777 Local Interface Tuple or be equal to the IR_local_iface_addr of 2778 any Removed Interface Address Tuple. 2780 o AL_dist MUST NOT be less than zero. 2782 In each Link Tuple: 2784 o L_neighbor_iface_addr_list MUST NOT contain the AL_net_addr of any 2785 Local Attached Network Tuple. 2787 o If L_status == SYMMETRIC and the Neighbor Tuple whose 2788 N_neighbor_iface_addr_list contains L_neighbor_iface_addr_list has 2789 N_mpr_selector == true, then, for each address in this 2790 L_neighbor_iface_addr_list, there MUST be an equal 2791 RY_neighbor_iface_addr in the Relay Set associated with the same 2792 OLSRv2 interface. 2794 In each Neighbor Tuple: 2796 o N_neighbor_iface_addr_list MUST NOT contain the AL_net_addr of any 2797 Local Attached Network Tuple. 2799 o If N_willingness MUST be in the range from WILL_NEVER to 2800 WILL_ALWAYS, inclusive. 2802 o If N_mpr == true, then N_symmetric MUST be true and N_willingness 2803 MUST NOT equal WILL_NEVER. 2805 o If N_symmetric == true and N_mpr == false, then N_willingness MUST 2806 NOT equal WILL_ALWAYS. 2808 o If N_mpr_selector == true, then N_symmetric MUST be true. 2810 o If N_mpr_selector == true, then, for each address in this 2811 N_neighbor_iface_addr_list, there MUST be an equal 2812 A_neighbor_iface_addr in the Advertised Neighbor Set. 2814 In each Lost Neighbor Tuple: 2816 o NL_neighbor_iface_addr MUST NOT equal the AL_net_addr of any Local 2817 Attached Network Tuple. 2819 In each 2-Hop Tuple: 2821 o N2_2hop_iface_addr MUST NOT equal the AL_net_addr of any Local 2822 Attached Network Tuple. 2824 In each Received Tuple: 2826 o RX_orig_addr MUST NOT equal this node's originator address or any 2827 O_orig_addr. 2829 o Each ordered triple (RX_type, RX_orig_addr, RX_seq_number) MUST 2830 NOT equal the corresponding triple in any other Received Tuple in 2831 the same Received Set. 2833 In each Processed Tuple: 2835 o P_orig_addr MUST NOT equal this node's originator address or any 2836 O_orig_addr. 2838 o Each ordered triple (P_type, P_orig_addr, P_seq_number) MUST NOT 2839 equal the corresponding triple in any other Processed Tuple. 2841 In each Forwarded Tuple: 2843 o F_orig_addr MUST NOT equal this node's originator address or any 2844 O_orig_addr. 2846 o Each ordered triple (F_type, F_orig_addr, F_seq_number) MUST NOT 2847 equal the corresponding triple in any other Forwarded Tuple. 2849 In each Relay Tuple: 2851 o RY_neighbor_iface_addr MUST NOT equal the RY_neighbor_iface_addr 2852 in any other Relay Tuple in the same Relay Set. 2854 o RY_neighbor_iface_addr MUST be in the L_neighbor_iface_addr_list 2855 of a Link Tuple with L_status == SYMMETRIC. 2857 In the Advertised Neighbor Set: 2859 o Each A_neighbor_iface_addr MUST NOT equal any other 2860 A_neighbor_iface_addr. 2862 o Each A_neighbor_iface_addr MUST be in the 2863 N_neighbor_iface_addr_list of a Neighbor Tuple with N_symmetric == 2864 true. 2866 In each Advertising Remote Node Tuple: 2868 o AR_orig_addr MUST NOT equal this node's originator address or any 2869 O_orig_addr. 2871 o AR_orig_addr MUST NOT equal the AR_orig_addr in any other ANSN 2872 History Tuple. 2874 o AR_iface_addr_list MUST NOT be empty. 2876 o AR_iface_addr_list MUST NOT contain any duplicated addresses. 2878 o AR_iface_addr_list MUST NOT contain any address which is in the 2879 I_local_iface_addr_list of any Local Interface Tuple or be equal 2880 to the IR_local_iface_addr of any Removed Interface Address Tuple. 2882 o AR_iface_addr_list MUST NOT contain any address which is the 2883 AL_net_addr of any Local Attached Network Tuple. 2885 In each Topology Tuple: 2887 o T_dest_iface_addr MUST NOT be in the I_local_iface_addr_list of 2888 any Local Interface Tuple or be equal to the IR_local_iface_addr 2889 of any Removed Interface Address Tuple. 2891 o T_dest_iface_addr MUST NOT equal the AL_net_addr of any Local 2892 Attached Network Tuple. 2894 o There MUST be an Advertising Remote Node Tuple with AR_orig_addr 2895 == T_orig_addr. 2897 o T_dest_iface_addr MUST NOT be in the AR_iface_addr_list of the 2898 Advertising Remote Node Tuple with AR_orig_addr == T_orig_addr. 2900 o T_seq_number MUST NOT be greater than AR_seq_number of the 2901 Advertising Remote Node Tuple with AR_orig_addr == T_orig_addr. 2903 o The ordered pair (T_dest_iface_addr, T_orig_addr) MUST NOT equal 2904 the corresponding pair in any other Topology Tuple. 2906 In each Attached Network Tuple: 2908 o AN_net_addr MUST NOT be in the I_local_iface_addr_list of any 2909 Local Interface Tuple or be equal to the IR_local_iface_addr of 2910 any Removed Interface Address Tuple. 2912 o AN_net_addr MUST NOT equal the AL_net_addr of any Local Attached 2913 Network Tuple. 2915 o There MUST be an Advertising Remote Node Tuple with AR_orig_addr 2916 == AN_orig_addr. 2918 o AN_seq_number MUST NOT be greater than AR_seq_number of the 2919 Advertising Remote Node Tuple with AR_orig_addr == AN_orig_addr. 2921 o AN_dist MUST NOT be less than zero. 2923 o The ordered pair (AN_net_addr, AN_orig_addr) MUST NOT equal the 2924 corresponding pair in any other Attached Network Tuple. 2926 Appendix F. Flow and Congestion Control 2928 Due to its proactive nature, the OLSRv2 protocol has a natural 2929 control over the flow of its control traffic. Nodes transmit control 2930 messages at predetermined rates specified and bounded by message 2931 intervals. 2933 OLSRv2 employs [nhdp] for local signaling, embedding MPR selection 2934 advertisement through a simple address block TLV, and node 2935 willingness advertisement (if any) as a single message TLV. OLSRv2 2936 local signaling, therefore, shares the characteristics and 2937 constraints of [nhdp]. 2939 Furthermore, MPR flooding greatly reduces signaling overhead from 2940 from link state information dissemination in two ways. First, the 2941 amount of link state information for a node to declare is reduced to 2942 only contain that node's MPR selectors. This reduces the size of a 2943 link state declaration as compared to declaring full link state 2944 information. In particular some nodes may not need to declare any 2945 such information. Second, using MPR flooding, the cost of 2946 distributing link state information throughout the network is greatly 2947 reduced, as compared to when using classic flooding, since only MPRs 2948 need to forward link state declaration messages. In dense networks, 2949 the reduction of control traffic can be of several orders of 2950 magnitude compared to routing protocols using classical flooding 2951 [MPR]. This feature naturally provides more bandwidth for useful 2952 data traffic and pushes further the frontier of congestion. 2954 Since the control traffic is continuous and periodic, it keeps the 2955 quality of the links used in routing more stable. However, using 2956 certain OLSRv2 options, some control messages (HELLO messages or TC 2957 messages) may be intentionally sent in advance of their deadline in 2958 order to increase the responsiveness of the protocol to topology 2959 changes. This may cause a small, temporary, and local increase of 2960 control traffic, however this is at all times bounded by the use of 2961 minimum message intervals. 2963 Appendix G. Contributors 2965 This specification is the result of the joint efforts of the 2966 following contributors -- listed alphabetically. 2968 o Cedric Adjih, INRIA, France, 2970 o Emmanuel Baccelli, INRIA , France, 2972 o Thomas Heide Clausen, LIX, France, 2974 o Justin Dean, NRL, USA, 2976 o Christopher Dearlove, BAE Systems, UK, 2977 2979 o Satoh Hiroki, Hitachi SDL, Japan, 2981 o Philippe Jacquet, INRIA, France, 2983 o Monden Kazuya, Hitachi SDL, Japan, 2985 o Kenichi Mase, Niigata University, Japan, 2987 o Ryuji Wakikawa, KEIO University, Japan, 2989 Appendix H. Acknowledgements 2991 The authors would like to acknowledge the team behind OLSRv1, 2992 specified in RFC3626, including Anis Laouiti (INT, Paris), Pascale 2993 Minet (INRIA, France), Laurent Viennot (INRIA, France), and Amir 2994 Qayyum (M.A. Jinnah University, Islamabad) for their contributions. 2996 The authors would like to gratefully acknowledge the following people 2997 for intense technical discussions, early reviews and comments on the 2998 specification and its components (listed alphabetically): Khaldoun Al 2999 Agha (LRI), Song-Yean Cho (LIX), Alan Cullen (BAE Systems), Louise 3000 Lamont (CRC), Li Li (CRC), Joe Macker (NRL), Richard Ogier (SRI), 3001 Charles E. Perkins (WiChorus), Shubhranshu Singh (Samsung AIT), and 3002 the entire IETF MANET working group. 3004 Authors' Addresses 3006 Thomas Heide Clausen 3007 LIX, Ecole Polytechnique, France 3009 Phone: +33 6 6058 9349 3010 EMail: T.Clausen@computer.org 3011 URI: http://www.ThomasClausen.org/ 3013 Christopher Dearlove 3014 BAE Systems Advanced Technology Centre 3016 Phone: +44 1245 242194 3017 EMail: chris.dearlove@baesystems.com 3018 URI: http://www.baesystems.com/ 3020 Philippe Jacquet 3021 Project Hipercom, INRIA 3023 Phone: +33 1 3963 5263 3024 EMail: philippe.jacquet@inria.fr 3026 The OLSRv2 Design Team 3027 MANET Working Group 3029 Full Copyright Statement 3031 Copyright (C) The IETF Trust (2008). 3033 This document is subject to the rights, licenses and restrictions 3034 contained in BCP 78, and except as set forth therein, the authors 3035 retain all their rights. 3037 This document and the information contained herein are provided on an 3038 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 3039 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 3040 THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 3041 OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 3042 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 3043 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 3045 Intellectual Property 3047 The IETF takes no position regarding the validity or scope of any 3048 Intellectual Property Rights or other rights that might be claimed to 3049 pertain to the implementation or use of the technology described in 3050 this document or the extent to which any license under such rights 3051 might or might not be available; nor does it represent that it has 3052 made any independent effort to identify any such rights. Information 3053 on the procedures with respect to rights in RFC documents can be 3054 found in BCP 78 and BCP 79. 3056 Copies of IPR disclosures made to the IETF Secretariat and any 3057 assurances of licenses to be made available, or the result of an 3058 attempt made to obtain a general license or permission for the use of 3059 such proprietary rights by implementers or users of this 3060 specification can be obtained from the IETF on-line IPR repository at 3061 http://www.ietf.org/ipr. 3063 The IETF invites any interested party to bring to its attention any 3064 copyrights, patents or patent applications, or other proprietary 3065 rights that may cover technology that may be required to implement 3066 this standard. Please address the information to the IETF at 3067 ietf-ipr@ietf.org.