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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) == Missing Reference: 'BCP38' is mentioned on line 1014, but not defined == Unused Reference: 'RFC2827' is defined on line 1285, but no explicit reference was found in the text ** Obsolete normative reference: RFC 5226 (Obsoleted by RFC 8126) ** Downref: Normative reference to an Informational RFC: RFC 7665 Summary: 2 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Service Function Chaining P. Quinn, Ed. 3 Internet-Draft Cisco Systems, Inc. 4 Intended status: Standards Track U. Elzur, Ed. 5 Expires: August 27, 2017 Intel 6 February 23, 2017 8 Network Service Header 9 draft-ietf-sfc-nsh-12.txt 11 Abstract 13 This document describes a Network Service Header (NSH) inserted onto 14 packets or frames to realize service function paths. NSH also 15 provides a mechanism for metadata exchange along the instantiated 16 service path. NSH is the SFC encapsulation required to support the 17 Service Function Chaining (SFC) Architecture (defined in RFC7665). 19 1. Requirements Language 21 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 22 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 23 document are to be interpreted as described in RFC 2119 [RFC2119]. 25 Status of this Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at http://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on August 27, 2017. 42 Copyright Notice 44 Copyright (c) 2017 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (http://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 Table of Contents 59 1. Requirements Language . . . . . . . . . . . . . . . . . . . . 2 60 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 61 2.1. Definition of Terms . . . . . . . . . . . . . . . . . . . 4 62 2.2. Problem Space . . . . . . . . . . . . . . . . . . . . . . 5 63 2.3. NSH-based Service Chaining . . . . . . . . . . . . . . . . 5 64 3. Network Service Header . . . . . . . . . . . . . . . . . . . . 7 65 3.1. Network Service Header Format . . . . . . . . . . . . . . 7 66 3.2. NSH Base Header . . . . . . . . . . . . . . . . . . . . . 7 67 3.3. Service Path Header . . . . . . . . . . . . . . . . . . . 10 68 3.4. NSH MD Type 1 . . . . . . . . . . . . . . . . . . . . . . 10 69 3.5. NSH MD Type 2 . . . . . . . . . . . . . . . . . . . . . . 11 70 3.5.1. Optional Variable Length Metadata . . . . . . . . . . 12 71 4. NSH Actions . . . . . . . . . . . . . . . . . . . . . . . . . 14 72 5. NSH Encapsulation . . . . . . . . . . . . . . . . . . . . . . 16 73 6. Fragmentation Considerations . . . . . . . . . . . . . . . . . 17 74 7. Service Path Forwarding with NSH . . . . . . . . . . . . . . . 18 75 7.1. SFFs and Overlay Selection . . . . . . . . . . . . . . . . 18 76 7.2. Mapping NSH to Network Transport . . . . . . . . . . . . . 20 77 7.3. Service Plane Visibility . . . . . . . . . . . . . . . . . 21 78 7.4. Service Graphs . . . . . . . . . . . . . . . . . . . . . . 21 79 8. Policy Enforcement with NSH . . . . . . . . . . . . . . . . . 22 80 8.1. NSH Metadata and Policy Enforcement . . . . . . . . . . . 22 81 8.2. Updating/Augmenting Metadata . . . . . . . . . . . . . . . 24 82 8.3. Service Path Identifier and Metadata . . . . . . . . . . . 25 83 9. Security Considerations . . . . . . . . . . . . . . . . . . . 27 84 10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 28 85 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 31 86 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32 87 12.1. NSH EtherType . . . . . . . . . . . . . . . . . . . . . . 32 88 12.2. Network Service Header (NSH) Parameters . . . . . . . . . 32 89 12.2.1. NSH Base Header Reserved Bits . . . . . . . . . . . . 32 90 12.2.2. NSH Version . . . . . . . . . . . . . . . . . . . . . 32 91 12.2.3. MD Type Registry . . . . . . . . . . . . . . . . . . . 32 92 12.2.4. MD Class Registry . . . . . . . . . . . . . . . . . . 33 93 12.2.5. NSH Base Header Next Protocol . . . . . . . . . . . . 33 94 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 35 95 13.1. Normative References . . . . . . . . . . . . . . . . . . . 35 96 13.2. Informative References . . . . . . . . . . . . . . . . . . 35 97 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 37 99 2. Introduction 101 Service functions are widely deployed and essential in many networks. 102 These service functions provide a range of features such as security, 103 WAN acceleration, and server load balancing. Service functions may 104 be instantiated at different points in the network infrastructure 105 such as the wide area network, data center, campus, and so forth. 107 Prior to development of the SFC architecture [RFC7665] and the 108 protocol specified in this document, current service function 109 deployment models have been relatively static, and bound to topology 110 for insertion and policy selection. Furthermore, they do not adapt 111 well to elastic service environments enabled by virtualization. 113 New data center network and cloud architectures require more flexible 114 service function deployment models. Additionally, the transition to 115 virtual platforms requires an agile service insertion model that 116 supports dynamic and elastic service delivery; the movement of 117 service functions and application workloads in the network and the 118 ability to easily bind service policy to granular information such as 119 per-subscriber state and steer traffic to the requisite service 120 function(s) are necessary. 122 NSH defines a new service plane protocol specifically for the 123 creation of dynamic service chains and is composed of the following 124 elements: 126 1. Service Function Path identification 128 2. Transport independent service function chain 130 3. Per-packet network and service metadata or optional variable 131 type-length-value (TLV) metadata. 133 NSH is designed to be easy to implement across a range of devices, 134 both physical and virtual, including hardware platforms. 136 An NSH-aware control plane is outside the scope of this document. 138 [RFC7665] provides an overview of a service chaining architecture 139 that clearly defines the roles of the various elements and the scope 140 of a service function chaining encapsulation. NSH is the SFC 141 encapsulation referenced in RFC7665. 143 2.1. Definition of Terms 144 Classification: Defined in [RFC7665]. 146 Classifier: Defined in [RFC7665]. 148 Metadata: Defined in [RFC7665]. 150 Network Locator: dataplane address, typically IPv4 or IPv6, used to 151 send and receive network traffic. 153 Network Node/Element: Device that forwards packets or frames based 154 on outer header (i.e. transport) information. 156 Network Overlay: Logical network built on top of existing network 157 (the underlay). Packets are encapsulated or tunneled to create 158 the overlay network topology. 160 Service Classifier: Logical entity providing classification 161 function. Since they are logical, classifiers may be co-resident 162 with SFC elements such as SFs or SFFs. Service classifiers 163 perform classification and impose NSH. The initial classifier 164 imposes the initial NSH and sends the NSH packet to the first SFF 165 in the path. Non-initial (i.e. subsequent) classification can 166 occur as needed and can alter, or create a new service path. 168 Service Function (SF): Defined in [RFC7665]. 170 Service Function Chain (SFC): Defined in [RFC7665]. 172 Service Function Forwarder (SFF): Defined in [RFC7665]. 174 Service Function Path (SFP): Defined in [RFC7665]. 176 SFC Proxy: Defined in [RFC7665]. 178 2.2. Problem Space 180 Network Service Header (NSH) addresses several limitations associated 181 with service function deployments. [RFC7498] provides a 182 comprehensive review of those issues. 184 2.3. NSH-based Service Chaining 186 The NSH creates a dedicated service plane, more specifically, NSH 187 enables: 189 1. Topological Independence: Service forwarding occurs within the 190 service plane, the underlying network topology does not require 191 modification. NSH provides an identifier used to select the 192 network overlay for network forwarding. 194 2. Service Chaining: NSH enables service chaining per [RFC7665]. 195 NSH contains path identification information needed to realize a 196 service path. Furthermore, NSH provides the ability to monitor 197 and troubleshoot a service chain, end-to-end via service-specific 198 OAM messages. The NSH fields can be used by administrators (via, 199 for example, a traffic analyzer) to verify (account, ensure 200 correct chaining, provide reports, etc.) the path specifics of 201 packets being forwarded along a service path. 203 3. NSH provides a mechanism to carry shared metadata between 204 participating entities and service functions. The semantics of 205 the shared metadata is communicated via a control plane, which is 206 outside the scope of this document, to participating nodes. 207 [SFC-CP] provides an example of such in section 3.3. Examples of 208 metadata include classification information used for policy 209 enforcement and network context for forwarding post service 210 delivery. 212 4. Classification and re-classification: sharing the metadata allows 213 service functions to share initial and intermediate 214 classification results with downstream service functions saving 215 re-classification, where enough information was enclosed. 217 5. NSH offers a common and standards-based header for service 218 chaining to all network and service nodes. 220 6. Transport Agnostic: NSH is transport independent. An appropriate 221 (for a given deployment) network transport protocol can be used 222 to transport NSH-encapsulated traffic. This transport may form 223 an overlay network and if an existing overlay topology provides 224 the required service path connectivity, that existing overlay may 225 be used. 227 3. Network Service Header 229 A Network Service Header (NSH) contains service path information and 230 optionally metadata that are added to a packet or frame and used to 231 create a service plane. An outer transport header is imposed, on NSH 232 and the original packet/frame, for network forwarding. 234 A Service Classifier adds the NSH. The NSH is removed by the last 235 SFF in the service chain or by a SF that consumes the packet. 237 3.1. Network Service Header Format 239 An NSH is composed of a 4-byte (all references to bytes in this draft 240 refer to 8-bit bytes, or octets) Base Header, a 4-byte Service Path 241 Header and Context Headers, as shown in Figure 1 below. 243 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 1 244 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 245 | Base Header | 246 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 247 | Service Path Header | 248 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 249 | | 250 ~ Context Headers ~ 251 | | 252 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 254 Figure 1: Network Service Header 256 Base header: provides information about the service header and the 257 payload protocol. 259 Service Path Header: provide path identification and location within 260 a service path. 262 Context headers: carry metadata (i.e. context data) along a service 263 path. 265 3.2. NSH Base Header 267 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 1 268 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 269 |Ver|O|C|R|R|R|R|R|R| Length | MD Type | Next Protocol | 270 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 271 Figure 2: NSH Base Header 273 Base Header Field Descriptions: 275 Version: The version field is used to ensure backward compatibility 276 going forward with future NSH updates. It MUST be set to 0x0 by the 277 sender, in this first revision of NSH. Given the widespread 278 implementation of existing hardware that uses the first nibble after 279 an MPLS label stack for ECMP decision processing, this document 280 reserves version 01 and this value MUST NOT be used in future 281 versions of the protocol. Please see [RFC7325] for further 282 discussion of MPLS-related forwarding requirements. 284 O bit: Setting this bit indicates an Operations, Administration, and 285 Maintenance (OAM) packet. The actual packet format and processing of 286 SFC OAM messages is outside the scope of this specification (see [I- 287 D.ietf-sfc-oam-framework]). 289 SF/SFF/SFC Proxy/Classifer implementations, which do not support SFC 290 OAM procedures, SHALL discard packets with O-bit set. 292 SF/SFF/SFC Proxy/Classifer implementations MAY support a configurable 293 parameter to enable forwarding received SFC OAM packets unmodified to 294 the next element in the chain. Such behavior may be acceptable for a 295 subset of OAM functions, but can result in unexpected outcomes for 296 others, thus it is recommended to analyze the impact of forwarding an 297 OAM packet for all OAM functions prior to enabling this behavior. 298 The configurable parameter MUST be disabled by default. 300 For non OAM packets, the O-bit MUST be cleared and MUST NOT be 301 modified along the SFP. 303 C bit: Indicates that a critical metadata TLV is present. This bit 304 acts as an indication for hardware implementers to decide how to 305 handle the presence of a critical TLV without necessarily needing to 306 parse all TLVs present. For an MD Type of 0x1 (i.e. no variable 307 length metadata is present), the C bit MUST be set to 0x0. 309 All other flag fields are reserved for future use. Reserved bits 310 MUST be set to zero when sent and MUST be ignored upon receipt. 312 Length: total length, in 4-byte words, of NSH including the Base 313 Header, the Service Path Header and the context headers or optional 314 variable length metadata. The Length MUST be of value 0x6 for MD 315 Type equal to 0x1 and MUST be of value 0x2 or greater for MD Type 316 equal to 0x2. The NSH header length MUST be an integer number of 4 317 bytes. The length field indicates the "end" of NSH and where the 318 original packet/frame begins. 320 MD Type: indicates the format of NSH beyond the mandatory Base Header 321 and the Service Path Header. MD Type defines the format of the 322 metadata being carried. Please see IANA Considerations section 323 below. 325 NSH defines two MD types: 327 0x1 - which indicates that the format of the header includes fixed 328 length context headers (see Figure 4 below). 330 0x2 - which does not mandate any headers beyond the Base Header and 331 Service Path Header, but may contain optional variable length context 332 information. 334 The format of the base header and the service path header is 335 invariant, and not affected by MD Type. 337 NSH implementations MUST support MD Type = 0x1, and SHOULD support MD 338 Type = 0x2. There exists, however, a middle ground, wherein a device 339 will support MD Type 0x1 (as per the MUST) metadata, yet be deployed 340 in a network with MD Type 0x2 metadata packets. In that case, the MD 341 Type 0x1 node, MUST utilize the base header length field to determine 342 the original payload offset if it requires access to the original 343 packet/frame. 345 Next Protocol: indicates the protocol type of the encapsulated data. 346 NSH does not alter the inner payload, and the semantics on the inner 347 protocol remain unchanged due to NSH service function chaining. 348 Please see IANA Considerations section below. 350 This draft defines the following Next Protocol values: 352 0x1 : IPv4 353 0x2 : IPv6 354 0x3 : Ethernet 355 0x4: NSH 356 0x5: MPLS 357 0x6-0xFD: Unassigned 358 0xFE-0xFF: Experimental 360 3.3. Service Path Header 362 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 1 363 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 364 | Service Path Identifier (SPI) | Service Index | 365 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 367 Service Path Identifier (SPI): 24 bits 368 Service Index (SI): 8 bits 370 Figure 3: NSH Service Path Header 372 Service Path Identifier (SPI): identifies a service path. 373 Participating nodes MUST use this identifier for Service Function 374 Path selection. The initial classifier MUST set the appropriate SPI 375 for a given classification result. 377 Service Index (SI): provides location within the SFP. The initial 378 classifier for a given SFP SHOULD set the SI to 255, however the 379 control plane MAY configure the initial value of SI as appropriate 380 (i.e. taking into account the length of the service function path). 381 Service Index MUST be decremented by Service Functions or by SFC 382 Proxy nodes after performing required services and the new 383 decremented SI value MUST be used in the egress NSH packet. The 384 initial Classifier MUST send the packet to the first SFF in the 385 identified SFP for forwarding along an SFP. If re-classification 386 occurs, and that re-classification results in a new SPI, the 387 (re)classifier is, in effect, the initial classifier for the 388 resultant SPI. 390 SI SHOULD be used in conjunction with Service Path Identifier for 391 Service Function Path Selection and for determining the next SFF/SF 392 in the path. Service Index (SI) is also valuable when 393 troubleshooting/ reporting service paths. In addition to indicating 394 the location within a Service Function Path, SI can be used for 395 service plane loop detection. 397 3.4. NSH MD Type 1 399 When the Base Header specifies MD Type = 0x1, four Context Headers, 400 4-byte each, MUST be added immediately following the Service Path 401 Header, as per Figure 4. Context Headers that carry no metadata MUST 402 be set to zero. 404 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 1 405 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 406 |Ver|O|C|R|R|R|R|R|R| Length | MD type=0x1 | Next Protocol | 407 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 408 | Service Path Identifer | Service Index | 409 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 410 | | 411 | Fixed Length Context Header | 412 | | 413 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 415 Figure 4: NSH MD Type=0x1 417 This specification does not make any assumption about the content 418 placed in the mandatory context field of the NSH header, and does not 419 describe the structure or meaning of the included metadata. 421 An SFC-aware SF MUST receive the data semantics first in order to 422 process the data placed in the mandatory context field. The data 423 semantics include both the allocation schema and the meaning of the 424 included data. How an SFC-aware SF gets the data semantics is 425 outside the scope of this specification. 427 Upon receiving an NSH MD-type 1 packet, if the SFC-aware SF is 428 configured for mandatory use of metadata but does not yet receive the 429 data semantics for the mandatory context field, it MUST NOT process 430 the packet and MUST log at least once per the SPI for which a 431 mandatory metadata is missing. 433 [dcalloc] and [broadalloc] provide specific examples of how metadata 434 can be allocated. 436 3.5. NSH MD Type 2 438 When the base header specifies MD Type= 0x2, zero or more Variable 439 Length Context Headers MAY be added, immediately following the 440 Service Path Header. Therefore, Length = 0x2, indicates that only 441 the Base Header followed by the Service Path Header are present. The 442 optional Variable Length Context Headers MUST be of an integer number 443 of 4-bytes. The base header length field MUST be used to determine 444 the offset to locate the original packet or frame for SFC nodes that 445 require access to that information. 447 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 1 448 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 449 |Ver|O|C|R|R|R|R|R|R| Length | MD Type=0x2 | Next Protocol | 450 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 451 | Service Path Identifier | Service Index | 452 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 453 | | 454 ~ Variable Length Context Headers (opt.) ~ 455 | | 456 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 458 Figure 5: NSH MD Type=0x2 460 3.5.1. Optional Variable Length Metadata 462 The format of the optional variable length context headers, is as 463 described below. 465 0 1 2 3 466 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 1 467 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 468 | Metadata Class |C| Type |R| Len | 469 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 470 | Variable Metadata | 471 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 473 Figure 6: Variable Context Headers 475 Metadata Class (MD Class): The MD Class defines the scope of the 476 'Type' field to provide a hierarchical namespace. The IANA 477 Considerations section defines how the MD Class values can be 478 allocated to standards bodies, vendors, and others. 480 Type: the Type field is split into two ranges - 0 to 127 for non- 481 critical options and 128-255 for critical options. While the value 482 allocation is the responsibility of the MD Class owner, critical 483 options MUST NOT be allocated from the 0 to 127 range and non- 484 critical options MUST NOT be allocated from the 128-255 range. 486 Figure 7 below illustrates the placement of the Critical bit within 487 the Type field. 489 +-+-+-+-+-+-+-+-+ 490 |C| Type | 491 +-+-+-+-+-+-+-+-+ 493 Figure 7: Critical Bit Placement Within the TLV Type Field 495 If an NSH-aware node receives an encapsulated packet containing a TLV 496 with the Critical bit set to 0x1 in the Type field and it does not 497 understand how to process the Type, it MUST drop the packet. Transit 498 devices (i.e. network nodes that do not participate in the service 499 plane) MUST NOT drop packets based on the setting of this bit. 501 Reserved bit: one reserved bit is present for future use. The 502 reserved bits MUST be set to 0x0. 504 Length: Length of the variable metadata, in single byte words. In 505 case the metadata length is not an integer number of 4-byte words, 506 the sender MUST add pad bytes immediately following the last metadata 507 byte to extend the metadata to an integer number of 4-byte words. 508 The receiver MUST round up the length field to the nearest 4-byte 509 word boundary, to locate and process the next field in the packet. 510 The receiver MUST access only those bytes in the metadata indicated 511 by the length field (i.e. actual number of single byte words) and 512 MUST ignore the remaining bytes up to the nearest 4-byte word 513 boundary. The Length may be 0 or greater. 515 A value of 0x0 denotes a TLV header without a Variable Metadata 516 field. 518 This specification does not make any assumption about TLVs that are 519 mandatory-to-implement or those that are mandatory-to-process. These 520 considerations are deployment-specific. However, the control plane 521 is entitled to instruct SFC-aware SFs with the data structure of TLVs 522 together with their scoping (see Section 3.3.3 of [SFC-CP]). 524 If multiple mandatory-to-process TLVs are required for a given SFP, 525 the control plane MAY instruct the SFC-aware SF with the order to 526 consume these TLVs. If no instructions are provided, the SFC-aware 527 SF MUST process these TLVs in the order their appear in the NSH 528 packet. 530 If multiple instances of the same TLV are included in an NSH packet, 531 but the definition of that TLV does not allow for it, the SFC-aware 532 SF MUST NOT process the packet and MUST log at least once per the SPI 533 for which multiple instances of that TLV is supplied. 535 4. NSH Actions 537 NSH-aware nodes are the only nodes that MAY alter the content of the 538 NSH headers. NSH-aware nodes include: service classifiers, SFF, SF 539 and SFC proxies. These nodes have several possible header related 540 actions: 542 1. Insert or remove NSH: These actions can occur at the start and 543 end respectively of a service path. Packets are classified, and 544 if determined to require servicing, NSH will be imposed. A 545 service classifier MUST insert NSH at the start of an SFP. An 546 imposed NSH MUST contain valid Base Header and Service Path 547 Header. At the end of a service function path, a SFF, MUST be 548 the last node operating on the service header and MUST remove it. 550 Multiple logical classifiers may exist within a given service 551 path. Non-initial classifiers may re-classify data and that re- 552 classification MAY result in a new Service Function Path. When 553 the logical classifier performs re-classification that results in 554 a change of service path, it MUST remove the existing NSH and 555 MUST impose a new NSH with the Base Header and Service Path 556 Header reflecting the new service path information and set the 557 initial SI. Metadata MAY be preserved in the new NSH. 559 2. Select service path: The Service Path Header provides service 560 chain information and is used by SFFs to determine correct 561 service path selection. SFFs MUST use the Service Path Header 562 for selecting the next SF or SFF in the service path. 564 3. Update NSH: NSH-aware service functions (SF) MUST decrement the 565 service index. If an SFF receives a packet with an SPI and SI 566 that do not correspond to a valid next hop in a valid Service 567 Function Path, that packet MUST be dropped by the SFF. 569 Classifier(s) MAY update Context Headers if new/updated context 570 is available. 572 If an SFC proxy is in use (acting on behalf of a non-NSH-aware 573 service function for NSH actions), then the proxy MUST update 574 Service Index and MAY update contexts. When an SFC proxy 575 receives an NSH-encapsulated packet, it MUST remove the NSH 576 headers before forwarding it to an NSH unaware SF. When the SFC 577 Proxy receives a packet back from an NSH unaware SF, it MUST re- 578 encapsulates it with the correct NSH, and MUST decrement the 579 Service Index. 581 4. Service policy selection: Service Function instances derive 582 policy (i.e. service actions such as permit or deny) selection 583 and enforcement from the service header. Metadata shared in the 584 service header can provide a range of service-relevant 585 information such as traffic classification. Service functions 586 SHOULD use NSH to select local service policy. 588 Figure 8 maps each of the four actions above to the components in the 589 SFC architecture that can perform it. 591 +---------------+------------------+-------+----------------+---------+ 592 | | Insert |Select | Update |Service | 593 | | or remove NSH |Service| NSH |policy | 594 | | |Function| |selection| 595 | Component +--------+--------+Path +----------------+ | 596 | | | | | Dec. |Update | | 597 | | Insert | Remove | |Service |Context| | 598 | | | | | Index |Header | | 599 +----------------+--------+--------+-------+--------+-------+---------+ 600 | | + | + | | | + | | 601 |Classifier | | | | | | | 602 +--------------- +--------+--------+-------+--------+-------+---------+ 603 |Service Function| | + | + | | | | 604 |Forwarder(SFF) | | | | | | | 605 +--------------- +--------+--------+-------+--------+-------+---------+ 606 |Service | | | | + | + | + | 607 |Function (SF) | | | | | | | 608 +--------------- +--------+--------+-------+--------+-------+---------+ 609 |SFC Proxy | + | + | | + | | | 610 +----------------+--------+--------+-------+--------+-------+---------+ 612 Figure 8: NSH Action and Role Mapping 614 5. NSH Encapsulation 616 Once NSH is added to a packet, an outer encapsulation is used to 617 forward the original packet and the associated metadata to the start 618 of a service chain. The encapsulation serves two purposes: 620 1. Creates a topologically independent services plane. Packets are 621 forwarded to the required services without changing the 622 underlying network topology 624 2. Transit network nodes simply forward the encapsulated packets as 625 is. 627 The service header is independent of the encapsulation used and is 628 encapsulated in existing transports. The presence of NSH is 629 indicated via protocol type or other indicator in the outer 630 encapsulation. 632 6. Fragmentation Considerations 634 NSH and the associated transport header are "added" to the 635 encapsulated packet/frame. This additional information increases the 636 size of the packet. 638 As discussed in [encap-considerations], within an administrative 639 domain, an operator can ensure that the underlay MTU is sufficient to 640 carry SFC traffic without requiring fragmentation. 642 However, there will be cases where the underlay MTU is not large 643 enough to carry the NSH traffic. Since NSH does not provide 644 fragmentation support at the service plane, the transport/overlay 645 layer MUST provide the requisite fragmentation handling. Section 6 646 of [encap-considerations] provides guidance for those scenarios. 648 7. Service Path Forwarding with NSH 650 7.1. SFFs and Overlay Selection 652 As described above, NSH contains a Service Path Identifier (SPI) and 653 a Service Index (SI). The SPI is, as per its name, an identifier. 654 The SPI alone cannot be used to forward packets along a service path. 655 Rather the SPI provide a level of indirection between the service 656 path/topology and the network transport. Furthermore, there is no 657 requirement, or expectation of an SPI being bound to a pre-determined 658 or static network path. 660 The Service Index provides an indication of location within a service 661 path. The combination of SPI and SI provides the identification of a 662 logical SF and its order within the service plane, and is used to 663 select the appropriate network locator(s) for overlay forwarding. 664 The logical SF may be a single SF, or a set of eligible SFs that are 665 equivalent. In the latter case, the SFF provides load distribution 666 amongst the collection of SFs as needed. 668 SI serves as a mechanism for detecting invalid service function path. 669 In particular, an SI value of zero indicates that forwarding is 670 incorrect and the packet must be discarded 672 This indirection -- path ID to overlay -- creates a true service 673 plane. That is the SFF/SF topology is constructed without impacting 674 the network topology but more importantly service plane only 675 participants (i.e. most SFs) need not be part of the network overlay 676 topology and its associated infrastructure (e.g. control plane, 677 routing tables, etc.). As mentioned above, an existing overlay 678 topology may be used provided it offers the requisite connectivity. 680 The mapping of SPI to transport occurs on an SFF (as discussed above, 681 the first SFF in the path gets a NSH encapsulated packet from the 682 Classifier). The SFF consults the SPI/ID values to determine the 683 appropriate overlay transport protocol (several may be used within a 684 given network) and next hop for the requisite SF. Figure 9 below 685 depicts an example of a single next-hop SPI/SI to network overlay 686 network locator mapping. 688 +-------------------------------------------------------+ 689 | SPI | SI | Next hop(s) | Transport | 690 +-------------------------------------------------------+ 691 | 10 | 255 | 192.0.2.1 | VXLAN-gpe | 692 | 10 | 254 | 198.51.100.10 | GRE | 693 | 10 | 251 | 198.51.100.15 | GRE | 694 | 40 | 251 | 198.51.100.15 | GRE | 695 | 50 | 200 | 01:23:45:67:89:ab | Ethernet | 696 | 15 | 212 | Null (end of path) | None | 697 +-------------------------------------------------------+ 699 Figure 9: SFF NSH Mapping Example 701 Additionally, further indirection is possible: the resolution of the 702 required SF network locator may be a localized resolution on an SFF, 703 rather than a service function chain control plane responsibility, as 704 per figures 10 and 11 below. 706 Please note: VXLAN-gpe and GRE in the above table refer to 707 [VXLAN-gpe] and [RFC2784], respectively. 709 +----------------------------+ 710 | SPI | SI | Next hop(s) | 711 +----------------------------+ 712 | 10 | 3 | SF2 | 713 | 245 | 12 | SF34 | 714 | 40 | 9 | SF9 | 715 +----------------------------+ 717 Figure 10: NSH to SF Mapping Example 719 +----------------------------------------+ 720 | SF | Next hop(s) | Transport | 721 +----------------------------------------| 722 | SF2 | 192.0.2.2 | VXLAN-gpe | 723 | SF34| 198.51.100.34 | UDP | 724 | SF9 | 2001:db8::1 | GRE | 725 +--------------------------+------------- 726 = 727 Figure 11: SF Locator Mapping Example 729 Since the SPI is a representation of the service path, the lookup may 730 return more than one possible next-hop within a service path for a 731 given SF, essentially a series of weighted (equally or otherwise) 732 paths to be used (for load distribution, redundancy or policy), see 733 Figure 12. The metric depicted in Figure 12 is an example to help 734 illustrated weighing SFs. In a real network, the metric will range 735 from a simple preference (similar to routing next- hop), to a true 736 dynamic composite metric based on some service function-centric state 737 (including load, sessions state, capacity, etc.) 739 +----------------------------------+ 740 | SPI | SI | NH | Metric | 741 +----------------------------------+ 742 | 10 | 3 | 203.0.113.1 | 1 | 743 | | | 203.0.113.2 | 1 | 744 | | | | | 745 | 20 | 12 | 192.0.2.1 | 1 | 746 | | | 203.0.113.4 | 1 | 747 | | | | | 748 | 30 | 7 | 192.0.2.10 | 10 | 749 | | | 198.51.100.1| 5 | 750 +----------------------------------+ 751 (encapsulation type omitted for formatting) 753 Figure 12: NSH Weighted Service Path 755 7.2. Mapping NSH to Network Transport 757 As described above, the mapping of SPI to network topology may result 758 in a single path, or it might result in a more complex topology. 759 Furthermore, the SPI to overlay mapping occurs at each SFF 760 independently. Any combination of topology selection is possible. 761 Please note, there is no requirement to create a new overlay topology 762 if a suitable one already existing. NSH packets can use any (new or 763 existing) overlay provided the requisite connectivity requirements 764 are satisfied. 766 Examples of mapping for a topology: 768 1. Next SF is located at SFFb with locator 2001:db8::1 769 SFFa mapping: SPI=10 --> VXLAN-gpe, dst-ip: 2001:db8::1 771 2. Next SF is located at SFFc with multiple network locators for 772 load distribution purposes: 773 SFFb mapping: SPI=10 --> VXLAN-gpe, dst_ip:203.0.113.1, 774 203.0.113.2, 203.0.113.3, equal cost 776 3. Next SF is located at SFFd with two paths from SFFc, one for 777 redundancy: 778 SFFc mapping: SPI=10 --> VXLAN-gpe, dst_ip:192.0.2.10 cost=10, 779 203.0.113.10, cost=20 781 In the above example, each SFF makes an independent decision about 782 the network overlay path and policy for that path. In other words, 783 there is no a priori mandate about how to forward packets in the 784 network (only the order of services that must be traversed). 786 The network operator retains the ability to engineer the network 787 paths as required. For example, the overlay path between SFFs may 788 utilize traffic engineering, QoS marking, or ECMP, without requiring 789 complex configuration and network protocol support to be extended to 790 the service path explicitly. In other words, the network operates as 791 expected, and evolves as required, as does the service plane. 793 7.3. Service Plane Visibility 795 The SPI and SI serve an important function for visibility into the 796 service topology. An operator can determine what service path a 797 packet is "on", and its location within that path simply by viewing 798 the NSH information (packet capture, IPFIX, etc.). The information 799 can be used for service scheduling and placement decisions, 800 troubleshooting and compliance verification. 802 7.4. Service Graphs 804 While a given realized service function path is a specific sequence 805 of service functions, the service as seen by a user can actually be a 806 collection of service function paths, with the interconnection 807 provided by classifiers (in-service path, non-initial 808 reclassification). These internal reclassifiers examine the packet 809 at relevant points in the network, and, if needed, SPI and SI are 810 updated (whether this update is a re-write, or the imposition of a 811 new NSH with new values is implementation specific) to reflect the 812 "result" of the classification. These classifiers may also of course 813 modify the metadata associated with the packet. 814 RFC7665, section 2.1 describes Service Graphs in detail. 816 8. Policy Enforcement with NSH 818 8.1. NSH Metadata and Policy Enforcement 820 As described in Section 3, NSH provides the ability to carry metadata 821 along a service path. This metadata may be derived from several 822 sources, common examples include: 824 Network nodes/devices: Information provided by network nodes can 825 indicate network-centric information (such as VRF or tenant) that 826 may be used by service functions, or conveyed to another network 827 node post service path egress. 829 External (to the network) systems: External systems, such as 830 orchestration systems, often contain information that is valuable 831 for service function policy decisions. In most cases, this 832 information cannot be deduced by network nodes. For example, a 833 cloud orchestration platform placing workloads "knows" what 834 application is being instantiated and can communicate this 835 information to all NSH nodes via metadata carried in the context 836 header(s). 838 Service Functions: A classifier co-resident with Service Functions 839 often perform very detailed and valuable classification. In some 840 cases they may terminate, and be able to inspect encrypted 841 traffic. 843 Regardless of the source, metadata reflects the "result" of 844 classification. The granularity of classification may vary. For 845 example, a network switch, acting as a classifier, might only be able 846 to classify based on a 5-tuple, whereas, a service function may be 847 able to inspect application information. Regardless of granularity, 848 the classification information can be represented in NSH. 850 Once the data is added to NSH, it is carried along the service path, 851 NSH-aware SFs receive the metadata, and can use that metadata for 852 local decisions and policy enforcement. The following two examples 853 highlight the relationship between metadata and policy: 855 +-------+ +-------+ +-------+ 856 | SFF )------->( SFF |------->| SFF | 857 +---^---+ +---|---+ +---|---+ 858 ,-|-. ,-|-. ,-|-. 859 / \ / \ / \ 860 ( Class ) SF1 ) ( SF2 ) 861 \ ify / \ / \ / 862 `---' `---' `---' 863 5-tuple: Permit Inspect 864 Tenant A Tenant A AppY 865 AppY 867 Figure 13: Metadata and Policy 869 +-----+ +-----+ +-----+ 870 | SFF |---------> | SFF |----------> | SFF | 871 +--+--+ +--+--+ +--+--+ 872 ^ | | 873 ,-+-. ,-+-. ,-+-. 874 / \ / \ / \ 875 ( Class ) ( SF1 ) ( SF2 ) 876 \ ify / \ / \ / 877 `-+-' `---' `---' 878 | Permit Deny AppZ 879 +---+---+ employees 880 | | 881 +-------+ 882 external 883 system: 884 Employee 885 AppZ 887 Figure 14: External Metadata and Policy 889 In both of the examples above, the service functions perform policy 890 decisions based on the result of the initial classification: the SFs 891 did not need to perform re-classification, rather they rely on a 892 antecedent classification for local policy enforcement. 894 Depending on the information carried in the metadata, data privacy 895 considerations may need to be considered. For example, if the 896 metadata conveys tenant information, that information may need to be 897 authenticated and/or encrypted between the originator and the 898 intended recipients (which may include intended SFs only) . NSH 899 itself does not provide privacy functions, rather it relies on the 900 transport/overlay layer. An operator can select the appropriate 901 transport to ensure the confidentially (and other security) 902 considerations are met. 904 8.2. Updating/Augmenting Metadata 906 Post-initial metadata imposition (typically performed during initial 907 service path determination), metadata may be augmented or updated: 909 1. Metadata Augmentation: Information may be added to NSH's existing 910 metadata, as depicted in Figure 15. For example, if the initial 911 classification returns the tenant information, a secondary 912 classification (perhaps co-resident with DPI or SLB) may augment 913 the tenant classification with application information, and 914 impose that new information in the NSH metadata. The tenant 915 classification is still valid and present, but additional 916 information has been added to it. 918 2. Metadata Update: Subsequent classifiers may update the initial 919 classification if it is determined to be incorrect or not 920 descriptive enough. For example, the initial classifier adds 921 metadata that describes the traffic as "internet" but a security 922 service function determines that the traffic is really "attack". 923 Figure 16 illustrates an example of updating metadata. 925 +-----+ +-----+ +-----+ 926 | SFF |---------> | SFF |----------> | SFF | 927 +--+--+ +--+--+ +--+--+ 928 ^ | | 929 ,---. ,---. ,---. 930 / \ / \ / \ 931 ( Class ) ( SF1 ) ( SF2 ) 932 \ / \ / \ / 933 `-+-' `---' `---' 934 | Inspect Deny 935 +---+---+ employees employee+ 936 | | Class=AppZ appZ 937 +-------+ 938 external 939 system: 940 Employee 942 Figure 15: Metadata Augmentation 944 +-----+ +-----+ +-----+ 945 | SFF |---------> | SFF |----------> | SFF | 946 +--+--+ +--+--+ +--+--+ 947 ^ | | 948 ,---. ,---. ,---. 949 / \ / \ / \ 950 ( Class ) ( SF1 ) ( SF2 ) 951 \ / \ / \ / 952 `---' `---' `---' 953 5-tuple: Inspect Deny 954 Tenant A Tenant A attack 955 --> attack 957 Figure 16: Metadata Update 959 8.3. Service Path Identifier and Metadata 961 Metadata information may influence the service path selection since 962 the Service Path Identifier values can represent the result of 963 classification. A given SPI can be defined based on classification 964 results (including metadata classification). The imposition of the 965 SPI and SI results in the packet being placed on the newly specified 966 SFP at the position indicated by the imposed SPI and SI. 968 This relationship provides the ability to create a dynamic service 969 plane based on complex classification without requiring each node to 970 be capable of such classification, or requiring a coupling to the 971 network topology. This yields service graph functionality as 972 described in Section 7.4. Figure 17 illustrates an example of this 973 behavior. 975 +-----+ +-----+ +-----+ 976 | SFF |---------> | SFF |------+---> | SFF | 977 +--+--+ +--+--+ | +--+--+ 978 | | | | 979 ,---. ,---. | ,---. 980 / \ / SF1 \ | / \ 981 ( SCL ) ( + ) | ( SF2 ) 982 \ / \SCL2 / | \ / 983 `---' `---' +-----+ `---' 984 5-tuple: Inspect | SFF | Original 985 Tenant A Tenant A +--+--+ next SF 986 --> DoS | 987 V 988 ,-+-. 989 / \ 990 ( SF10 ) 991 \ / 992 `---' 993 DoS 994 "Scrubber" 996 Figure 17: Path ID and Metadata 998 Specific algorithms for mapping metadata to an SPI are outside the 999 scope of this document. 1001 9. Security Considerations 1003 As with many other protocols, NSH data can be spoofed or otherwise 1004 modified. In many deployments, NSH will be used in a controlled 1005 environment, with trusted devices (e.g. a data center) thus 1006 mitigating the risk of unauthorized header manipulation. 1008 NSH is always encapsulated in a transport protocol and therefore, 1009 when required, existing security protocols that provide authenticity 1010 (e.g. [RFC6071]) can be used. Similarly, if confidentiality is 1011 required, existing encryption protocols can be used in conjunction 1012 with encapsulated NSH. 1014 Further, existing best practices, such as [BCP38] should be deployed 1015 at the network layer to ensure that traffic entering the service path 1016 is indeed "valid". [encap-considerations] provides additional 1017 transport encapsulation considerations. 1019 NSH metadata authenticity and confidentially must be considered as 1020 well. In order to protect the metadata, an operator can leverage the 1021 aforementioned mechanisms provided the transport layer, authenticity 1022 and/or confidentiality. An operator MUST carefully select the 1023 transport/underlay services to ensure end to end security services, 1024 when those are sought after. For example, if [RFC6071] is used, the 1025 operator MUST ensure it can be supported by the transport/underlay of 1026 all relevant network segments as well as SFF and SFs. Further, as 1027 described in [section 8.1], operators can and should use indirect 1028 identification for personally identifying information, thus 1029 significantly mitigating the risk of privacy violation. 1031 Lastly, SF security, although out of scope of this document, should 1032 be considered, particularly if an SF needs to access, authenticate or 1033 update NSH metadata. 1035 10. Contributors 1037 This WG document originated as draft-quinn-sfc-nsh and had the 1038 following co-authors and contributors. The editors of this document 1039 would like to thank and recognize them and their contributions. 1040 These co-authors and contributors provided invaluable concepts and 1041 content for this document's creation. 1043 Surendra Kumar 1044 Cisco Systems 1045 smkumar@cisco.com 1047 Michael Smith 1048 Cisco Systems 1049 michsmit@cisco.com 1051 Jim Guichard 1052 Cisco Systems 1053 jguichar@cisco.com 1055 Rex Fernando 1056 Cisco Systems 1057 Email: rex@cisco.com 1059 Navindra Yadav 1060 Cisco Systems 1061 Email: nyadav@cisco.com 1063 Wim Henderickx 1064 Alcatel-Lucent 1065 wim.henderickx@alcatel-lucent.com 1067 Andrew Dolganow 1068 Alcaltel-Lucent 1069 Email: andrew.dolganow@alcatel-lucent.com 1071 Praveen Muley 1072 Alcaltel-Lucent 1073 Email: praveen.muley@alcatel-lucent.com 1075 Tom Nadeau 1076 Brocade 1077 tnadeau@lucidvision.com 1079 Puneet Agarwal 1080 puneet@acm.org 1082 Rajeev Manur 1083 Broadcom 1084 rmanur@broadcom.com 1086 Abhishek Chauhan 1087 Citrix 1088 Abhishek.Chauhan@citrix.com 1090 Joel Halpern 1091 Ericsson 1092 joel.halpern@ericsson.com 1094 Sumandra Majee 1095 F5 1096 S.Majee@f5.com 1098 David Melman 1099 Marvell 1100 davidme@marvell.com 1102 Pankaj Garg 1103 Microsoft 1104 pankajg@microsoft.com 1106 Brad McConnell 1107 Rackspace 1108 bmcconne@rackspace.com 1110 Chris Wright 1111 Red Hat Inc. 1112 chrisw@redhat.com 1114 Kevin Glavin 1115 Riverbed 1116 kevin.glavin@riverbed.com 1118 Hong (Cathy) Zhang 1119 Huawei US R&D 1120 cathy.h.zhang@huawei.com 1122 Louis Fourie 1123 Huawei US R&D 1124 louis.fourie@huawei.com 1126 Ron Parker 1127 Affirmed Networks 1128 ron_parker@affirmednetworks.com 1130 Myo Zarny 1131 Goldman Sachs 1132 myo.zarny@gs.com 1134 11. Acknowledgments 1136 The authors would like to thank Sunil Vallamkonda, Nagaraj Bagepalli, 1137 Abhijit Patra, Peter Bosch, Darrel Lewis, Pritesh Kothari, Tal 1138 Mizrahi and Ken Gray for their detailed review, comments and 1139 contributions. 1141 A special thank you goes to David Ward and Tom Edsall for their 1142 guidance and feedback. 1144 Additionally the authors would like to thank Carlos Pignataro and 1145 Larry Kreeger for their invaluable ideas and contributions which are 1146 reflected throughout this document. 1148 Loa Andersson provided a thorough review and valuable comments, we 1149 thank him for that. 1151 Reinaldo Penno deserves a particular thank you for his architecture 1152 and implementation work that helped guide the protocol concepts and 1153 design. 1155 Lastly, David Dolson has provides significant review, feedback and 1156 suggestions throughout the evolution of this document. His 1157 contributions are very much appreciated. 1159 12. IANA Considerations 1161 12.1. NSH EtherType 1163 An IEEE EtherType, 0x894F, has been allocated for NSH. 1165 12.2. Network Service Header (NSH) Parameters 1167 IANA is requested to create a new "Network Service Header (NSH) 1168 Parameters" registry. The following sub-sections request new 1169 registries within the "Network Service Header (NSH) Parameters " 1170 registry. 1172 12.2.1. NSH Base Header Reserved Bits 1174 There are ten bits at the beginning of the NSH Base Header. New bits 1175 are assigned via Standards Action [RFC5226]. 1177 Bits 0-1 - Version 1178 Bit 2 - OAM (O bit) 1179 Bit 3 - Critical TLV (C bit) 1180 Bits 4-9 - Reserved 1182 12.2.2. NSH Version 1184 IANA is requested to setup a registry of "NSH Version". New values 1185 are assigned via Standards Action [RFC5226]. 1187 Version 00: This protocol version. This document. 1188 Version 01: Reserved. This document. 1189 Version 10: Unassigned. 1190 Version 11: Unassigned. 1192 12.2.3. MD Type Registry 1194 IANA is requested to set up a registry of "MD Types". These are 1195 8-bit values. MD Type values 0, 1, 2, 254, and 255 are specified in 1196 this document. Registry entries are assigned by using the "IETF 1197 Review" policy defined in RFC 5226 [RFC5226]. 1199 +---------+--------------+---------------+ 1200 | MD Type | Description | Reference | 1201 +---------+--------------+---------------+ 1202 | 0 | Reserved | This document | 1203 | | | | 1204 | 1 | NSH | This document | 1205 | | | | 1206 | 2 | NSH | This document | 1207 | | | | 1208 | 3..253 | Unassigned | | 1209 | | | | 1210 | 254 | Experiment 1 | This document | 1211 | | | | 1212 | 255 | Experiment 2 | This document | 1213 +---------+--------------+---------------+ 1215 Table 1 1217 12.2.4. MD Class Registry 1219 IANA is requested to set up a registry of "MD Class". These are 16- 1220 bit values. MD Classes defined by this document are assigned as 1221 follows: 1223 0x0000 to 0x01ff: IETF Review 1224 0x0200 to 0xfff5: Expert Review 1225 0xfff6 to 0xfffe: Experimental 1226 0xffff: Reserved 1228 12.2.5. NSH Base Header Next Protocol 1230 IANA is requested to set up a registry of "Next Protocol". These are 1231 8-bit values. Next Protocol values 0, 1, 2, 3, 4 and 5 are defined 1232 in this draft. New values are assigned via "Expert Reviews" as per 1233 [RFC5226]. 1235 +---------------+--------------+---------------+ 1236 | Next Protocol | Description | Reference | 1237 +---------------+--------------+---------------+ 1238 | 0 | Reserved | This document | 1239 | | | | 1240 | 1 | IPv4 | This document | 1241 | | | | 1242 | 2 | IPv6 | This document | 1243 | | | | 1244 | 3 | Ethernet | This document | 1245 | | | | 1246 | 4 | NSH | This document | 1247 | | | | 1248 | 5 | MPLS | This document | 1249 | | | | 1250 | 6..253 | Unassigned | | 1251 | | | | 1252 | 254 | Experiment 1 | This document | 1253 | | | | 1254 | 255 | Experiment 2 | This document | 1255 +---------------+--------------+---------------+ 1257 Table 2 1259 13. References 1261 13.1. Normative References 1263 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1264 Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ 1265 RFC2119, March 1997, 1266 . 1268 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1269 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 1270 DOI 10.17487/RFC5226, May 2008, 1271 . 1273 [RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function 1274 Chaining (SFC) Architecture", RFC 7665, DOI 10.17487/ 1275 RFC7665, October 2015, 1276 . 1278 13.2. Informative References 1280 [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. 1281 Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, 1282 DOI 10.17487/RFC2784, March 2000, 1283 . 1285 [RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering: 1286 Defeating Denial of Service Attacks which employ IP Source 1287 Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827, 1288 May 2000, . 1290 [RFC6071] Frankel, S. and S. Krishnan, "IP Security (IPsec) and 1291 Internet Key Exchange (IKE) Document Roadmap", RFC 6071, 1292 DOI 10.17487/RFC6071, February 2011, 1293 . 1295 [RFC7325] Villamizar, C., Ed., Kompella, K., Amante, S., Malis, A., 1296 and C. Pignataro, "MPLS Forwarding Compliance and 1297 Performance Requirements", RFC 7325, DOI 10.17487/RFC7325, 1298 August 2014, . 1300 [RFC7498] Quinn, P., Ed. and T. Nadeau, Ed., "Problem Statement for 1301 Service Function Chaining", RFC 7498, DOI 10.17487/ 1302 RFC7498, April 2015, 1303 . 1305 [SFC-CP] Boucadair, M., "Service Function Chaining (SFC) Control 1306 Plane Components & Requirements", 2016, . 1309 [VXLAN-gpe] 1310 Quinn, P., Manur, R., Agarwal, P., Kreeger, L., Lewis, D., 1311 Maino, F., Smith, M., Yong, L., Xu, X., Elzur, U., Garg, 1312 P., and D. Melman, "Generic Protocol Extension for VXLAN", 1313 . 1316 [bcp38] Ferguson, P. and D. Senie, "Network Ingress Filtering: 1317 Defeating Denial of Service Attacks which employ IP Source 1318 Address Spoofing", 2000, 1319 . 1321 [broadalloc] 1322 Napper, J., Kumar, S., Muley, P., and W. Hendericks, "NSH 1323 Context Header Allocation -- Mobility", 2016, . 1327 [dcalloc] Guichard, J., Smith, M., and et al., "Network Service 1328 Header (NSH) Context Header Allocation (Data Center)", 1329 2016, . 1332 [encap-considerations] 1333 Nordmark, E., Tian, A., Gross, J., Hudson, J., Kreeger, 1334 L., Garg, P., Thaler, P., and T. Herbert, "Encapsulation 1335 Considerations", . 1338 [nsh-env-req] 1339 Migault, D., Pignataro, C., Reddy, T., and C. Inacio, "SFC 1340 environment Security requirements", 2016, . 1344 Authors' Addresses 1346 Paul Quinn (editor) 1347 Cisco Systems, Inc. 1349 Email: paulq@cisco.com 1351 Uri Elzur (editor) 1352 Intel 1354 Email: uri.elzur@intel.com