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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Possible downref: Non-RFC (?) normative reference: ref. 'IPSP' ** Downref: Normative reference to an Informational RFC: RFC 4541 == Outdated reference: draft-ietf-6man-default-iids has been published as RFC 8064 -- Obsolete informational reference (is this intentional?): RFC 3633 (Obsoleted by RFC 8415) Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 6Lo Working Group J. Nieminen 3 Internet-Draft T. Savolainen 4 Intended status: Standards Track M. Isomaki 5 Expires: December 13, 2014 Nokia 6 B. Patil 7 AT&T 8 Z. Shelby 9 Arm 10 C. Gomez 11 Universitat Politecnica de Catalunya/i2CAT 12 June 11, 2014 14 Transmission of IPv6 Packets over BLUETOOTH(R) Low Energy 15 draft-ietf-6lo-btle-02 17 Abstract 19 Bluetooth Smart is the brand name for the Bluetooth low energy 20 feature in the Bluetooth specification defined by the Bluetooth 21 Special Interest Group. The standard Bluetooth radio has been widely 22 implemented and available in mobile phones, notebook computers, audio 23 headsets and many other devices. The low power version of Bluetooth 24 is a specification that enables the use of this air interface with 25 devices such as sensors, smart meters, appliances, etc. The low 26 power variant of Bluetooth is standardized since the revision 4.0 of 27 the Bluetooth specifications, although version 4.1 or newer is 28 required for IPv6. This document describes how IPv6 is transported 29 over Bluetooth low energy using 6LoWPAN techniques. 31 Status of This Memo 33 This Internet-Draft is submitted in full conformance with the 34 provisions of BCP 78 and BCP 79. 36 Internet-Drafts are working documents of the Internet Engineering 37 Task Force (IETF). Note that other groups may also distribute 38 working documents as Internet-Drafts. The list of current Internet- 39 Drafts is at http://datatracker.ietf.org/drafts/current/. 41 Internet-Drafts are draft documents valid for a maximum of six months 42 and may be updated, replaced, or obsoleted by other documents at any 43 time. It is inappropriate to use Internet-Drafts as reference 44 material or to cite them other than as "work in progress." 46 This Internet-Draft will expire on December 13, 2014. 48 Copyright Notice 50 Copyright (c) 2014 IETF Trust and the persons identified as the 51 document authors. All rights reserved. 53 This document is subject to BCP 78 and the IETF Trust's Legal 54 Provisions Relating to IETF Documents 55 (http://trustee.ietf.org/license-info) in effect on the date of 56 publication of this document. Please review these documents 57 carefully, as they describe your rights and restrictions with respect 58 to this document. Code Components extracted from this document must 59 include Simplified BSD License text as described in Section 4.e of 60 the Trust Legal Provisions and are provided without warranty as 61 described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 66 1.1. Terminology and Requirements Language . . . . . . . . . . 3 67 2. Bluetooth Low Energy . . . . . . . . . . . . . . . . . . . . 3 68 2.1. Bluetooth LE stack . . . . . . . . . . . . . . . . . . . 4 69 2.2. Link layer roles and topology . . . . . . . . . . . . . . 5 70 2.3. Bluetooth LE device addressing . . . . . . . . . . . . . 5 71 2.4. Bluetooth LE packets sizes and MTU . . . . . . . . . . . 6 72 3. Specification of IPv6 over Bluetooth Low Energy . . . . . . . 6 73 3.1. Protocol stack . . . . . . . . . . . . . . . . . . . . . 6 74 3.2. Link model . . . . . . . . . . . . . . . . . . . . . . . 7 75 3.2.1. Stateless address autoconfiguration . . . . . . . . . 8 76 3.2.2. Neighbor discovery . . . . . . . . . . . . . . . . . 8 77 3.2.3. Header compression . . . . . . . . . . . . . . . . . 9 78 3.2.3.1. Remote destination example . . . . . . . . . . . 10 79 3.2.4. Unicast and Multicast address mapping . . . . . . . . 11 80 3.3. Internet connectivity scenarios . . . . . . . . . . . . . 11 81 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 82 5. Security Considerations . . . . . . . . . . . . . . . . . . . 12 83 6. Additional contributors . . . . . . . . . . . . . . . . . . . 13 84 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 85 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 86 8.1. Normative References . . . . . . . . . . . . . . . . . . 13 87 8.2. Informative References . . . . . . . . . . . . . . . . . 14 88 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 90 1. Introduction 92 Bluetooth low energy (LE) is a radio technology targeted for devices 93 that operate with coin cell batteries or minimalistic power sources, 94 which means that low power consumption is essential. Bluetooth LE is 95 an especially attractive technology for Internet of Things 96 applications, such as health monitors, environmental sensing, 97 proximity applications and many others. 99 Considering the potential for the exponential growth in the number of 100 sensors and Internet connected devices and things, IPv6 is an ideal 101 protocol due to the large address space it provides. In addition, 102 IPv6 provides tools for stateless address autoconfiguration, which is 103 particularly suitable for sensor network applications and nodes which 104 have very limited processing power or lack a full-fledged operating 105 system. 107 RFC 4944 [RFC4944] specifies the transmission of IPv6 over IEEE 108 802.15.4. The Bluetooth LE link in many respects has similar 109 characteristics to that of IEEE 802.15.4. Many of the mechanisms 110 defined in the RFC 4944 can be applied to the transmission of IPv6 on 111 Bluetooth LE links. This document specifies the details of IPv6 112 transmission over Bluetooth LE links. 114 1.1. Terminology and Requirements Language 116 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 117 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 118 document are to be interpreted as described in RFC 2119 [RFC2119]. 120 The terms 6LN, 6LR and 6LBR are defined as in [RFC6775], with an 121 addition that Bluetooth LE central and Bluetooth LE peripheral (see 122 Section 2.2) can both be either 6LN or 6LBR. 124 2. Bluetooth Low Energy 126 Bluetooth LE is designed for transferring small amounts of data 127 infrequently at modest data rates at a very low cost per bit. 128 Bluetooth Special Interest Group (Bluetooth SIG) has introduced two 129 trademarks, Bluetooth Smart for single-mode devices (a device that 130 only supports Bluetooth LE) and Bluetooth Smart Ready for dual-mode 131 devices (devices that support both Bluetooth and Bluetooth LE). In 132 the rest of the document, the term Bluetooth LE refers to both types 133 of devices. 135 Bluetooth LE was introduced in Bluetooth 4.0 and further enhanced in 136 Bluetooth 4.1 [BTCorev4.1]. Bluetooth SIG will also publish Internet 137 Protocol Support Profile (IPSP) [IPSP], which includes Internet 138 Protocol Support Service (IPSS) and that enables discovery of IP- 139 enabled devices and establishment of link-layer connection for 140 transporting IPv6 packets. IPv6 over Bluetooth LE is dependent on 141 both Bluetooth 4.1 and IPSP. 143 Devices such as mobile phones, notebooks, tablets and other handheld 144 computing devices which will include Bluetooth 4.1 chipsets will also 145 have the low-energy functionality of Bluetooth. Bluetooth LE will 146 also be included in many different types of accessories that 147 collaborate with mobile devices such as phones, tablets and notebook 148 computers. An example of a use case for a Bluetooth LE accessory is 149 a heart rate monitor that sends data via the mobile phone to a server 150 on the Internet. 152 2.1. Bluetooth LE stack 154 The lower layer of the Bluetooth LE stack consists of the Physical 155 (PHY) and the Link Layer (LL). The Physical Layer transmits and 156 receives the actual packets. The Link Layer is responsible for 157 providing medium access, connection establishment, error control and 158 flow control. The upper layer consists of the Logical Link Control 159 and Adaptation Protocol (L2CAP), Attribute Protocol (ATT), Generic 160 Attribute Profile (GATT) and Generic Access Profile (GAP) as shown in 161 Figure 1. The device internal Host Controller Interface (HCI) 162 separates the lower layers, often implemented in the Bluetooth 163 controller, from higher layers, often implemented in the host stack. 164 GATT and Bluetooth LE profiles together enable the creation of 165 applications in a standardized way without using IP. L2CAP provides 166 multiplexing capability by multiplexing the data channels from the 167 above layers. L2CAP also provides fragmentation and reassembly for 168 large data packets. 170 +-------------------------------------------------+ 171 | Applications | 172 +---------------------------------------+---------+ 173 | Generic Attribute Profile | Generic | 174 +--------------------+------------------+ Access | 175 | Attribute Protocol | Security Manager | Profile | 176 +--------------------+------------------+---------+ 177 | Logical Link Control and Adaptation Protocol | 178 - - -+-----------------------+-------------------------+- - - HCI 179 | Link Layer | Direct Test Mode | 180 +-------------------------------------------------+ 181 | Physical Layer | 182 +-------------------------------------------------+ 184 Figure 1: Bluetooth LE Protocol Stack 186 2.2. Link layer roles and topology 188 Bluetooth LE defines two GAP roles of relevance herein: the Bluetooth 189 LE central role and the Bluetooth LE peripheral role. A device in 190 the central role, which is called central from now on, has 191 traditionally been able to manage multiple simultaneous connections 192 with a number of devices in the peripheral role, called peripherals 193 from now on. A peripheral is commonly connected to a single central, 194 but since Bluetooth 4.1 can also connect to multiple centrals. In 195 this document for IPv6 networking purposes the Bluetooth LE network 196 (i.e. a Bluetooth LE piconet) follows a star topology shown in the 197 Figure 2, where the router typically implements the Bluetooth LE 198 central role and nodes implement the Bluetooth LE peripheral role. 199 In the future mesh networking may be defined for IPv6 over Bluetooth 200 LE. 202 Node --. .-- Node 203 \ / 204 Node ---- Router ---- Node 205 / \ 206 Node --' '-- Node 208 Figure 2: Bluetooth LE Star Topology 210 In Bluetooth LE a central is assumed to be less constrained than a 211 peripheral. Hence, in the primary deployment scenario central and 212 peripheral will act as 6LoWPAN Border Router (6LBR) and a 6LoWPAN 213 Node (6LN), respectively. 215 In Bluetooth LE, direct communication only takes place between a 216 central and a peripheral. Hence, in a Bluetooth LE network using 217 IPv6, a radio hop is equivalent to an IPv6 link and vice versa. 219 2.3. Bluetooth LE device addressing 221 Every Bluetooth LE device is identified by a 48-bit device address. 222 The Bluetooth specification describes the device address of a 223 Bluetooth LE device as:"Devices are identified using a device 224 address. Device addresses may be either a public device address or a 225 random device address." [BTCorev4.1]. The public device addresses 226 are based on the IEEE 802-2001 standard [IEEE802-2001]. The random 227 device addresses are generated as defined in the Bluetooth 228 specification. The device addresses are always unique within a 229 Bluetooth LE piconet, but the random addresses are not guaranteed to 230 be globally unique. 232 2.4. Bluetooth LE packets sizes and MTU 234 Optimal MTU defined for L2CAP fixed channels over Bluetooth LE is 27 235 bytes including the L2CAP header of four bytes. Default MTU for 236 Bluetooth LE is hence defined to be 27 bytes. Therefore, excluding 237 L2CAP header of four bytes, protocol data unit (PDU) size of 23 bytes 238 is available for upper layers. In order to be able to transmit IPv6 239 packets of 1280 bytes or larger, link layer fragmentation and 240 reassembly solution is provided by the L2CAP layer. The IPSP defines 241 means for negotiating up a link-layer connection that provides MTU of 242 1280 bytes or higher for the IPv6 layer [IPSP]. The link-layer MTU 243 is negotiated separately for each direction. Implementations that 244 require single link-layer MTU value SHALL use the smallest of the 245 possibly different MTU values. 247 3. Specification of IPv6 over Bluetooth Low Energy 249 Before any IP-layer communications can take place over Bluetooth LE, 250 Bluetooth LE enabled nodes such as 6LNs and 6LBRs have to find each 251 other and establish a suitable link-layer connection. The discovery 252 and Bluetooth LE connection setup procedures are documented by 253 Bluetooth SIG in the IPSP specification [IPSP], and hence are out of 254 scope of this document. The IPSP depends on Bluetooth version 4.1, 255 and hence both Bluetooth version 4.1 or newer and IPSP are required 256 for IPv6 communications. 258 Bluetooth LE technology sets strict requirements for low power 259 consumption and thus limits the allowed protocol overhead. 6LoWPAN 260 standards [RFC6775], and [RFC6282] provide useful functionality for 261 reducing overhead which can be applied to Bluetooth LE. This 262 functionality comprises of link-local IPv6 addresses and stateless 263 IPv6 address autoconfiguration (see Section 3.2.1), Neighbor 264 Discovery (see Section 3.2.2) and header compression (see 265 Section 3.2.3). 267 A significant difference between IEEE 802.15.4 and Bluetooth LE is 268 that the former supports both star and mesh topology (and requires a 269 routing protocol), whereas Bluetooth LE does not currently support 270 the formation of multihop networks at the link layer. 272 3.1. Protocol stack 274 Figure 3 illustrates IPv6 over Bluetooth LE stack including the 275 Internet Protocol Support Service. UDP and TCP are provided as 276 examples of transport protocols, but the stack can be used by any 277 other upper layer protocol capable of running atop of IPv6. The 278 6LoWPAN layer runs on top of Bluetooth LE L2CAP layer. 280 +---------+ +----------------------------+ 281 | IPSS | | UDP/TCP/other | 282 +---------+ +----------------------------+ 283 | GATT | | IPv6 | 284 +---------+ +----------------------------+ 285 | ATT | | 6LoWPAN for Bluetooth LE | 286 +---------+--+----------------------------+ 287 | Bluetooth LE L2CAP | 288 - - +-----------------------------------------+- - - HCI 289 | Bluetooth LE Link Layer | 290 +-----------------------------------------+ 291 | Bluetooth LE Physical | 292 +-----------------------------------------+ 294 Figure 3: IPv6 over Bluetooth LE Stack 296 3.2. Link model 298 The concept of IPv6 link (layer 3) and the physical link (combination 299 of PHY and MAC) needs to be clear and the relationship has to be well 300 understood in order to specify the addressing scheme for transmitting 301 IPv6 packets over the Bluetooth LE link. RFC 4861 [RFC4861] defines 302 a link as "a communication facility or medium over which nodes can 303 communicate at the link layer, i.e., the layer immediately below 304 IPv6." 306 In the case of Bluetooth LE, 6LoWPAN layer is adapted to support 307 transmission of IPv6 packets over Bluetooth LE. The IPSP defines all 308 steps required for setting up the Bluetooth LE connection over which 309 6LoWPAN can function [IPSP], including handling the link-layer 310 fragmentation required on Bluetooth LE, as described in Section 2.4. 312 This specification also assumes the IPv6 header compression format 313 specified in RFC 6282 is used [RFC6282]. It is also assumed that the 314 IPv6 payload length can be inferred from the L2CAP header length and 315 the IID value inferred from the link-layer address with help of 316 Neighbor Cache, if elided from compressed packet header. 318 Bluetooth LE connections used to build a star topology are point-to- 319 point in nature, as Bluetooth broadcast features are not used for 320 IPv6 over Bluetooth LE. 6LN-to-6LN communications, e.g. using link- 321 local addresses, need to be bridged by the 6LBR. The 6LBR ensures 322 address collisions do not occur (see Section 3.2.2). 324 After the peripheral and central have connected at the Bluetooth LE 325 level, the link can be considered up and IPv6 address configuration 326 and transmission can begin. 328 3.2.1. Stateless address autoconfiguration 330 A Bluetooth LE 6LN performs stateless address autoconfiguration as 331 per RFC 4862 [RFC4862]. A 64-bit Interface identifier (IID) for a 332 Bluetooth LE interface MAY be formed by utilizing the 48-bit 333 Bluetooth device address (see Section 2.3) as defined in RFC 2464 334 "IPv6 over Ethernet" specification [RFC2464]. Alternatively, a 335 randomly generated IID (see Section 3.2.2) can be used instead, for 336 example, as discussed in [I-D.ietf-6man-default-iids]. In the case 337 of randomly generated IID or randomly generated Bluetooth device 338 address, the "Universal/Local" bit MUST be set to 0 [RFC4291]. Only 339 if the Bluetooth device address is known to be a public address the 340 "Universal/Local" bit can be set to 1. 342 As defined in RFC 4291 [RFC4291], the IPv6 link-local address for a 343 Bluetooth LE node is formed by appending the IID, to the prefix 344 FE80::/64, as depicted in Figure 4. 346 10 bits 54 bits 64 bits 347 +----------+-----------------+----------------------+ 348 |1111111010| zeros | Interface Identifier | 349 +----------+-----------------+----------------------+ 351 Figure 4: IPv6 link-local address in Bluetooth LE 353 The tool for a 6LBR to obtain an IPv6 prefix for numbering the 354 Bluetooth LE network is out of scope of this document, but can be, 355 for example, accomplished via DHCPv6 Prefix Delegation [RFC3633] or 356 by using Unique Local IPv6 Unicast Addresses (ULA) [RFC4193]. Due to 357 the link model of the Bluetooth LE (see Section 2.2) the 6LBR MUST 358 set the "on-link" flag (L) to zero in the Prefix Information Option 359 [RFC4861]. This will cause 6LNs to always send packets to the 6LBR, 360 including the case when the destination is another 6LN using the same 361 prefix. 363 3.2.2. Neighbor discovery 365 'Neighbor Discovery Optimization for IPv6 over Low-Power Wireless 366 Personal Area Networks (6LoWPANs)' [RFC6775] describes the neighbor 367 discovery approach as adapted for use in several 6LoWPAN topologies, 368 including the mesh topology. Bluetooth LE does not support mesh 369 networks and hence only those aspects that apply to a star topology 370 are considered. 372 The following aspects of the Neighbor Discovery optimizations 373 [RFC6775] are applicable to Bluetooth LE 6LNs: 375 1. A Bluetooth LE 6LN MUST register its addresses with the 6LBR by 376 sending a Neighbor Solicitation (NS) message with the Address 377 Registration Option (ARO) and process the Neighbor Advertisement (NA) 378 accordingly. The NS with the ARO option MUST be sent irrespective of 379 the method used to generate the IID. The 6LN MUST register only one 380 IPv6 address per IPv6 prefix available on a link. 382 2. For sending Router Solicitations and processing Router 383 Advertisements the Bluetooth LE 6LNs MUST, respectively, follow 384 Sections 5.3 and 5.4 of the [RFC6775]. 386 3.2.3. Header compression 388 Header compression as defined in RFC 6282 [RFC6282], which specifies 389 the compression format for IPv6 datagrams on top of IEEE 802.15.4, is 390 REQUIRED in this document as the basis for IPv6 header compression on 391 top of Bluetooth LE. All headers MUST be compressed according to RFC 392 6282 [RFC6282] encoding formats. 394 The Bluetooth LE's star topology structure and ARO can be exploited 395 in order to provide a mechanism for IID compression. The following 396 text describes the principles of IPv6 address compression on top of 397 Bluetooth LE. 399 The ARO option requires use of EUI-64 identifier [RFC6775]. In the 400 case of Bluetooth LE, the field SHALL be filled with the 48-bit 401 device address used by the Bluetooth LE node converted into 64-bit 402 Modified EUI-64 format [RFC4291]. 404 To enable efficient header compression, the 6LBR MUST include 6LoWPAN 405 Context Option (6CO) [RFC6775] for all prefixes the 6LBR advertises 406 in Router Advertisements for use in stateless address 407 autoconfiguration. 409 When a 6LN is sending a packet to or through a 6LBR, it MUST fully 410 elide the source address it has registered with ARO to the 6LBR for 411 the indicated prefix. That is, if SAC=0 and SAM=11 the 6LN MUST have 412 registered the source link-local IPv6 address it is using using ARO, 413 and if SAC=1 and SAM=11 the 6LN MUST have registered the source IPv6 414 address with the prefix related to compression context identified 415 with Context Identifier Extension. The destination IPv6 address MUST 416 be fully elided if the destination address is the same address to 417 which the 6LN has succesfully registered its source IPv6 address with 418 ARO (set DAC=0, DAM=11). The destination IPv6 address MUST be fully 419 or partially elided if context has been set up for the destination 420 address. For example, DAC=0 and DAM=01 when destination prefix is 421 link-local, and DAC=1 and DAM=01 with Context Identifier Extension if 422 compression context has been configured for the used destination 423 prefix. 425 When a 6LBR is transmitting packets to 6LN, it MUST fully elide the 426 source IID if the source IPv6 address is the one 6LN has used to 427 register its address with ARO (set SAC=0, SAM=11), and it MUST elide 428 the source prefix or address if a compression context related to the 429 IPv6 source address has been set up. The 6LBR also MUST elide the 430 destination IPv6 address registered by the 6LN with ARO and thus 6LN 431 can determine it based on indication of link-local prefix (DAC=0) or 432 indication of other prefix (DAC=1 with Context Identifier Extension). 434 3.2.3.1. Remote destination example 436 When a 6LN transmits an IPv6 packet to a remote destination using 437 global Unicast IPv6 addresses, if a context is defined for the 6LN's 438 global IPv6 address, the 6LN has to indicate this context in the 439 corresponding source fields of the compressed IPv6 header as per 440 Section 3.1 of RFC 6282 [RFC6282], and has to elide the full IPv6 441 source address previously registered with ARO. For this, the 6LN 442 MUST use the following settings in the IPv6 compressed header: CID=1, 443 SAC=1, SAM=11. In this case, the 6LBR can infer the elided IPv6 444 source address since 1) the 6LBR has previously assigned the prefix 445 to the 6LNs; and 2) the 6LBR maintains a Neighbor Cache that relates 446 the Device Address and the IID the device has registered with ARO. 447 If a context is defined for the IPv6 destination address, the 6LN has 448 to also indicate this context in the corresponding destination fields 449 of the compressed IPv6 header, and elide the prefix of or the full 450 destination IPv6 address. For this, the 6LN MUST set the DAM field 451 of the compressed IPv6 header as DAM=01 (if the context covers a 452 64-bit prefix) or as DAM=11 (if the context covers a full, 128-bit 453 address). CID and DAC MUST be set to CID=1 and DAC=1. Note that 454 when a context is defined for the IPv6 destination address, the 6LBR 455 can infer the elided destination prefix by using the context. 457 When a 6LBR receives an IPv6 packet sent by a remote node outside the 458 Bluetooth LE network, and the destination of the packet is a 6LN, if 459 a context is defined for the prefix of the 6LN's global IPv6 address, 460 the 6LBR has to indicate this context in the corresponding 461 destination fields of the compressed IPv6 header. The 6LBR has to 462 elide the IPv6 destination address of the packet before forwarding 463 it, if the IPv6 destination address is inferable by the 6LN. For 464 this, the 6LBR will set the DAM field of the IPv6 compressed header 465 as DAM=11. CID and DAC needs to be set to CID=1 and DAC=1. If a 466 context is defined for the IPv6 source address, the 6LBR needs to 467 indicate this context in the source fields of the compressed IPv6 468 header, and elide that prefix as well. For this, the 6LBR needs to 469 set the SAM field of the IPv6 compressed header as SAM=01 (if the 470 context covers a 64-bit prefix) or SAM=11 (if the context covers a 471 full, 128-bit address). CID and SAC are to be set to CID=1 and 472 SAC=1. 474 3.2.4. Unicast and Multicast address mapping 476 The Bluetooth LE link layer does not support multicast. Hence 477 traffic is always unicast between two Bluetooth LE nodes. Even in 478 the case where a 6LBR is attached to multiple 6LNs, the 6LBR cannot 479 do a multicast to all the connected 6LNs. If the 6LBR needs to send 480 a multicast packet to all its 6LNs, it has to replicate the packet 481 and unicast it on each link. However, this may not be energy- 482 efficient and particular care must be taken if the master is battery- 483 powered. In the opposite direction, a 6LN always has to send packets 484 to or through 6LBR. Hence, when a 6LN needs to transmit an IPv6 485 multicast packet, the 6LN will unicast the corresponding Bluetooth LE 486 packet to the 6LBR. The 6LBR will then forward the multicast packet 487 to other 6LNs. To avoid excess of unwanted multicast traffic being 488 sent to 6LNs, the 6LBR SHOULD implement MLD Snooping feature 489 [RFC4541]. 491 3.3. Internet connectivity scenarios 493 In a typical scenario, the Bluetooth LE network is connected to the 494 Internet as shown in the Figure 5. 496 6LN 497 \ ____________ 498 \ / \ 499 6LN ---- 6LBR ----- | Internet | 500 / \____________/ 501 / 502 6LN 504 <-- Bluetooth LE --> 506 Figure 5: Bluetooth LE network connected to the Internet 508 In some scenarios, the Bluetooth LE network may transiently or 509 permanently be an isolated network as shown in the Figure 6. 511 6LN 6LN 512 \ / 513 \ / 514 6LN --- 6LBR --- 6LN 515 / \ 516 / \ 517 6LN 6LN 519 <--- Bluetooth LE ---> 521 Figure 6: Isolated Bluetooth LE network 523 It is also possible to have point-to-point connection between two 524 6LNs, one of which being central and another being peripheral. 525 Similarly, it is possible to have point-to-point connections between 526 two 6LBRs, one of which being central and another being peripheral. 528 At this point in time mesh networking with Bluetooth LE is not 529 specified. 531 In the isolated network scenario communications between 6LN and 6LBR 532 can use IPv6 link-local methodology, but for communications between 533 different 6LNs, the 6LBR has to number the network with ULA prefix 534 [RFC4193], and route packets between 6LNs. 536 4. IANA Considerations 538 There are no IANA considerations related to this document. 540 5. Security Considerations 542 The transmission of IPv6 over Bluetooth LE links has similar 543 requirements and concerns for security as for IEEE 802.15.4. 544 Bluetooth LE Link Layer security considerations are covered by the 545 IPSP [IPSP]. 547 Bluetooth LE Link Layer supports encryption and authentication by 548 using the Counter with CBC-MAC (CCM) mechanism [RFC3610] and a 549 128-bit AES block cipher. Upper layer security mechanisms may 550 exploit this functionality when it is available. (Note: CCM does not 551 consume bytes from the maximum per-packet L2CAP data size, since the 552 link layer data unit has a specific field for them when they are 553 used.) 555 Key management in Bluetooth LE is provided by the Security Manager 556 Protocol (SMP), as defined in [BTCorev4.1]. 558 6. Additional contributors 560 Kanji Kerai, Jari Mutikainen, David Canfeng-Chen and Minjun Xi from 561 Nokia have contributed significantly to this document. 563 7. Acknowledgements 565 The Bluetooth, Bluetooth Smart and Bluetooth Smart Ready marks are 566 registred trademarks owned by Bluetooth SIG, Inc. 568 Samita Chakrabarti, Erik Nordmark, and Marcel De Kogel have provided 569 valuable feedback for this draft. 571 Authors would like to give special acknowledgements for Krishna 572 Shingala, Frank Berntsen, and Bluetooth SIG's Internet Working Group 573 for providing significant feedback and improvement proposals for this 574 document. 576 8. References 578 8.1. Normative References 580 [BTCorev4.1] 581 Bluetooth Special Interest Group, "Bluetooth Core 582 Specification Version 4.1", December 2013. 584 [IPSP] Bluetooth Special Interest Group, "Bluetooth Internet 585 Protocol Support Profile Specification - REFERENCE TO BE 586 UPDATED ONCE IPSP IS PUBLISHED", 2014. 588 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 589 Requirement Levels", BCP 14, RFC 2119, March 1997. 591 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 592 Networks", RFC 2464, December 1998. 594 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 595 Architecture", RFC 4291, February 2006. 597 [RFC4541] Christensen, M., Kimball, K., and F. Solensky, 598 "Considerations for Internet Group Management Protocol 599 (IGMP) and Multicast Listener Discovery (MLD) Snooping 600 Switches", RFC 4541, May 2006. 602 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 603 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 604 September 2007. 606 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 607 Address Autoconfiguration", RFC 4862, September 2007. 609 [RFC6282] Hui, J. and P. Thubert, "Compression Format for IPv6 610 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, 611 September 2011. 613 [RFC6775] Shelby, Z., Chakrabarti, S., Nordmark, E., and C. Bormann, 614 "Neighbor Discovery Optimization for IPv6 over Low-Power 615 Wireless Personal Area Networks (6LoWPANs)", RFC 6775, 616 November 2012. 618 8.2. Informative References 620 [I-D.ietf-6man-default-iids] 621 Gont, F., Cooper, A., Thaler, D., and W. Will, 622 "Recommendation on Stable IPv6 Interface Identifiers", 623 draft-ietf-6man-default-iids-00 (work in progress), 624 January 2014. 626 [IEEE802-2001] 627 Institute of Electrical and Electronics Engineers (IEEE), 628 "IEEE 802-2001 Standard for Local and Metropolitan Area 629 Networks: Overview and Architecture", 2002. 631 [RFC3610] Whiting, D., Housley, R., and N. Ferguson, "Counter with 632 CBC-MAC (CCM)", RFC 3610, September 2003. 634 [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic 635 Host Configuration Protocol (DHCP) version 6", RFC 3633, 636 December 2003. 638 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 639 Addresses", RFC 4193, October 2005. 641 [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, 642 "Transmission of IPv6 Packets over IEEE 802.15.4 643 Networks", RFC 4944, September 2007. 645 Authors' Addresses 647 Johanna Nieminen 648 Nokia 649 Itamerenkatu 11-13 650 Helsinki 00180 651 Finland 653 Email: johannamaria.nieminen@gmail.com 654 Teemu Savolainen 655 Nokia 656 Hermiankatu 12 D 657 Tampere 33720 658 Finland 660 Email: teemu.savolainen@nokia.com 662 Markus Isomaki 663 Nokia 664 Keilalahdentie 2-4 665 Espoo 02150 666 Finland 668 Email: markus.isomaki@nokia.com 670 Basavaraj Patil 671 AT&T 672 1410 E. Renner Road 673 Richardson, TX 75082 674 USA 676 Email: basavaraj.patil@att.com 678 Zach Shelby 679 Arm 680 Hallituskatu 13-17D 681 Oulu 90100 682 Finland 684 Email: zach.shelby@arm.com 686 Carles Gomez 687 Universitat Politecnica de Catalunya/i2CAT 688 C/Esteve Terradas, 7 689 Castelldefels 08860 690 Spain 692 Email: carlesgo@entel.upc.edu