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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) == Unused Reference: 'RFC0791' is defined on line 1274, but no explicit reference was found in the text == Unused Reference: 'RFC2784' is defined on line 1282, but no explicit reference was found in the text == Unused Reference: 'VXLAN-gpe' is defined on line 1304, but no explicit reference was found in the text -- Obsolete informational reference (is this intentional?): RFC 5226 (Obsoleted by RFC 8126) Summary: 0 errors (**), 0 flaws (~~), 6 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group P. Quinn 3 Internet-Draft J. Guichard 4 Intended status: Standards Track S. Kumar 5 Expires: August 28, 2015 M. Smith 6 Cisco Systems, Inc. 7 W. Henderickx 8 Alcatel-Lucent 9 T. Nadeau 10 Brocade 11 P. Agarwal 13 R. Manur 14 Broadcom 15 A. Chauhan 16 Citrix 17 J. Halpern 18 Ericsson 19 S. Majee 20 F5 21 U. Elzur 22 Intel 23 D. Melman 24 Marvell 25 P. Garg 26 Microsoft 27 B. McConnell 28 Rackspace 29 C. Wright 30 Red Hat Inc. 31 K. Glavin 32 Riverbed 33 C. Zhang 34 L. Fourie 35 Huawei US R&D 36 R. Parker 37 Affirmed Networks 38 M. Zarny 39 Goldman Sachs 40 February 24, 2015 42 Network Service Header 43 draft-quinn-sfc-nsh-07.txt 45 Abstract 47 This draft describes a Network Service Header (NSH) inserted onto 48 encapsulated packets or frames to realize service function paths. 50 NSH also provides a mechanism for metadata exchange along the 51 instantiated service path. 53 1. Requirements Language 55 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 56 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 57 document are to be interpreted as described in RFC 2119 [RFC2119]. 59 Status of this Memo 61 This Internet-Draft is submitted in full conformance with the 62 provisions of BCP 78 and BCP 79. 64 Internet-Drafts are working documents of the Internet Engineering 65 Task Force (IETF). Note that other groups may also distribute 66 working documents as Internet-Drafts. The list of current Internet- 67 Drafts is at http://datatracker.ietf.org/drafts/current/. 69 Internet-Drafts are draft documents valid for a maximum of six months 70 and may be updated, replaced, or obsoleted by other documents at any 71 time. It is inappropriate to use Internet-Drafts as reference 72 material or to cite them other than as "work in progress." 74 This Internet-Draft will expire on August 28, 2015. 76 Copyright Notice 78 Copyright (c) 2015 IETF Trust and the persons identified as the 79 document authors. All rights reserved. 81 This document is subject to BCP 78 and the IETF Trust's Legal 82 Provisions Relating to IETF Documents 83 (http://trustee.ietf.org/license-info) in effect on the date of 84 publication of this document. Please review these documents 85 carefully, as they describe your rights and restrictions with respect 86 to this document. Code Components extracted from this document must 87 include Simplified BSD License text as described in Section 4.e of 88 the Trust Legal Provisions and are provided without warranty as 89 described in the Simplified BSD License. 91 Table of Contents 93 1. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 94 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 95 2.1. Definition of Terms . . . . . . . . . . . . . . . . . . . 5 96 2.2. Problem Space . . . . . . . . . . . . . . . . . . . . . . 7 97 3. Network Service Header . . . . . . . . . . . . . . . . . . . . 9 98 3.1. Network Service Header Format . . . . . . . . . . . . . . 9 99 3.2. NSH Base Header . . . . . . . . . . . . . . . . . . . . . 9 100 3.3. Service Path Header . . . . . . . . . . . . . . . . . . . 11 101 3.4. NSH MD-type 1 . . . . . . . . . . . . . . . . . . . . . . 11 102 3.4.1. Mandatory Context Header Allocation Guidelines . . . . 12 103 3.5. NSH MD-type 2 . . . . . . . . . . . . . . . . . . . . . . 13 104 3.5.1. Optional Variable Length Metadata . . . . . . . . . . 14 105 4. NSH Actions . . . . . . . . . . . . . . . . . . . . . . . . . 16 106 5. NSH Encapsulation . . . . . . . . . . . . . . . . . . . . . . 18 107 6. NSH Usage . . . . . . . . . . . . . . . . . . . . . . . . . . 19 108 7. NSH Proxy Nodes . . . . . . . . . . . . . . . . . . . . . . . 20 109 8. Fragmentation Considerations . . . . . . . . . . . . . . . . . 21 110 9. Service Path Forwarding with NSH . . . . . . . . . . . . . . . 22 111 9.1. SFFs and Overlay Selection . . . . . . . . . . . . . . . . 22 112 9.2. Mapping NSH to Network Overlay . . . . . . . . . . . . . . 24 113 9.3. Service Plane Visibility . . . . . . . . . . . . . . . . . 25 114 9.4. Service Graphs . . . . . . . . . . . . . . . . . . . . . . 25 115 10. Policy Enforcement with NSH . . . . . . . . . . . . . . . . . 27 116 10.1. NSH Metadata and Policy Enforcement . . . . . . . . . . . 27 117 10.2. Updating/Augmenting Metadata . . . . . . . . . . . . . . . 28 118 10.3. Service Path ID and Metadata . . . . . . . . . . . . . . . 30 119 11. NSH Encapsulation Examples . . . . . . . . . . . . . . . . . . 31 120 11.1. GRE + NSH . . . . . . . . . . . . . . . . . . . . . . . . 31 121 11.2. VXLAN-gpe + NSH . . . . . . . . . . . . . . . . . . . . . 31 122 11.3. Ethernet + NSH . . . . . . . . . . . . . . . . . . . . . . 32 123 12. Security Considerations . . . . . . . . . . . . . . . . . . . 33 124 13. Open Items for WG Discussion . . . . . . . . . . . . . . . . . 34 125 14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 35 126 15. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 36 127 16. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 37 128 16.1. NSH EtherType . . . . . . . . . . . . . . . . . . . . . . 37 129 16.2. Network Service Header (NSH) Parameters . . . . . . . . . 37 130 16.2.1. NSH Base Header Reserved Bits . . . . . . . . . . . . 37 131 16.2.2. MD Type Registry . . . . . . . . . . . . . . . . . . . 37 132 16.2.3. TLV Class Registry . . . . . . . . . . . . . . . . . . 38 133 16.2.4. NSH Base Header Next Protocol . . . . . . . . . . . . 38 134 17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 39 135 17.1. Normative References . . . . . . . . . . . . . . . . . . . 39 136 17.2. Informative References . . . . . . . . . . . . . . . . . . 39 137 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 41 139 2. Introduction 141 Service functions are widely deployed and essential in many networks. 142 These service functions provide a range of features such as security, 143 WAN acceleration, and server load balancing. Service functions may 144 be instantiated at different points in the network infrastructure 145 such as the wide area network, data center, campus, and so forth. 147 The current service function deployment models are relatively static, 148 and bound to topology for insertion and policy selection. 149 Furthermore, they do not adapt well to elastic service environments 150 enabled by virtualization. 152 New data center network and cloud architectures require more flexible 153 service function deployment models. Additionally, the transition to 154 virtual platforms requires an agile service insertion model that 155 supports elastic service delivery; the movement of service functions 156 and application workloads in the network and the ability to easily 157 bind service policy to granular information such as per-subscriber 158 state are necessary. 160 The approach taken by NSH is composed of the following elements: 162 1. Service path identification 164 2. Transport independent per-packet/frame service metadata. 166 3. Optional variable TLV metadata. 168 NSH is designed to be easy to implement across a range of devices, 169 both physical and virtual, including hardware platforms. 171 An NSH aware control plane is outside the scope of this document. 173 The SFC Architecture document [SFC-arch] provides an overview of a 174 service chaining architecture that clearly defines the roles of the 175 various elements and the scope of a service function chaining 176 encapsulation. 178 2.1. Definition of Terms 180 Classification: Locally instantiated policy and customer/network/ 181 service profile matching of traffic flows for identification of 182 appropriate outbound forwarding actions. 184 SFC Network Forwarder (NF): SFC network forwarders provide network 185 connectivity for service functions forwarders and service 186 functions. SFC network forwarders participate in the network 187 overlay used for service function chaining as well as in the SFC 188 encapsulation. 190 Service Function Forwarder (SFF): A service function forwarder is 191 responsible for delivering traffic received from the NF to one or 192 more connected service functions, and from service functions to 193 the NF. 195 Service Function (SF): A function that is responsible for specific 196 treatment of received packets. A service function can act at the 197 network layer or other OSI layers. A service function can be a 198 virtual instance or be embedded in a physical network element. 199 One of multiple service functions can be embedded in the same 200 network element. Multiple instances of the service function can 201 be enabled in the same administrative domain. 203 Service Node (SN): Physical or virtual element that hosts one or 204 more service functions and has one or more network locators 205 associated with it for reachability and service delivery. 207 Service Function Chain (SFC): A service function chain defines an 208 ordered set of service functions that must be applied to packets 209 and/or frames selected as a result of classification. The implied 210 order may not be a linear progression as the architecture allows 211 for nodes that copy to more than one branch. The term service 212 chain is often used as shorthand for service function chain. 214 Service Function Path (SFP): The instantiation of a SFC in the 215 network. Packets follow a service function path from a classifier 216 through the requisite service functions 218 Network Node/Element: Device that forwards packets or frames based 219 on outer header information. In most cases is not aware of the 220 presence of NSH. 222 Network Overlay: Logical network built on top of existing network 223 (the underlay). Packets are encapsulated or tunneled to create 224 the overlay network topology. 226 Network Service Header: Data plane header added to frames/packets. 227 The header contains information required for service chaining, as 228 well as metadata added and consumed by network nodes and service 229 elements. 231 Service Classifier: Function that performs classification and 232 imposes an NSH. Creates a service path. Non-initial (i.e. 233 subsequent) classification can occur as needed and can alter, or 234 create a new service path. 236 Service Hop: NSH aware node, akin to an IP hop but in the service 237 overlay. 239 Service Path Segment: A segment of a service path overlay. 241 NSH Proxy: Acts as a gateway: removes and inserts NSH on behalf of a 242 service function that is not NSH aware. 244 2.2. Problem Space 246 Network Service Header (NSH) addresses several limitations associated 247 with service function deployments today. 249 1. Topological Dependencies: Network service deployments are often 250 coupled to network topology. Such dependency imposes constraints 251 on the service delivery, potentially inhibiting the network 252 operator from optimally utilizing service resources, and reduces 253 the flexibility. This limits scale, capacity, and redundancy 254 across network resources. 256 2. Service Chain Construction: Service function chains today are 257 most typically built through manual configuration processes. 258 These are slow and error prone. With the advent of newer service 259 deployment models the control/management planes provide not only 260 connectivity state, but will also be increasingly utilized for 261 the creation of network services. Such a control/management 262 planes could be centralized, or be distributed. 264 3. Application of Service Policy: Service functions rely on topology 265 information such as VLANs or packet (re) classification to 266 determine service policy selection, i.e. the service function 267 specific action taken. Topology information is increasingly less 268 viable due to scaling, tenancy and complexity reasons. The 269 topological information is often stale, providing the operator 270 with inaccurate placement that can result in suboptimal resource 271 utilization. Furthermore topology-centric information often does 272 not convey adequate information to the service functions, forcing 273 functions to individually perform more granular classification. 275 4. Per-Service (re)Classification: Classification occurs at each 276 service function independent from previously applied service 277 functions. More importantly, the classification functionality 278 often differs per service function and service functions may not 279 leverage the results from other service functions. 281 5. Common Header Format: Various proprietary methods are used to 282 share metadata and create service paths. An open header provides 283 a common format for all network and service devices. 285 6. Limited End-to-End Service Visibility: Troubleshooting service 286 related issues is a complex process that involve both network- 287 specific and service-specific expertise. This is especially the 288 case when service function chains span multiple DCs, or across 289 administrative boundaries. Furthermore, the physical and virtual 290 environments (network and service) can be highly divergent in 291 terms of topology and that topological variance adds to these 292 challenges. 294 7. Transport Dependence: Service functions can and will be deployed 295 in networks with a range of transports requiring service 296 functions to support and participate in many transports (and 297 associated control planes) or for a transport gateway function to 298 be present. 300 Please see the Service Function Chaining Problem Statement [SFC-PS] 301 for a more detailed analysis of service function deployment problem 302 areas. 304 3. Network Service Header 306 A Network Service Header (NSH) contains metadata and service path 307 information that are added to a packet or frame and used to create a 308 service plane. The packets and the NSH are then encapsulated in an 309 outer header for transport. 311 The service header is added by a service classification function - a 312 device or application - that determines which packets require 313 servicing, and correspondingly which service path to follow to apply 314 the appropriate service. 316 3.1. Network Service Header Format 318 An NSH is composed of a 4-byte base header, a 4-byte service path 319 header and context headers, as shown in Figure 1 below. 321 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 1 322 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 323 | Base Header | 324 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 325 | Service Path Header | 326 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 327 | | 328 ~ Context Headers ~ 329 | | 330 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 332 Figure 1: Network Service Header 334 Base header: provides information about the service header and the 335 payload protocol. 337 Service Path Header: provide path identification and location within 338 a path. 340 Context headers: carry opaque metadata and variable length encoded 341 information. 343 3.2. NSH Base Header 345 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 1 346 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 347 |Ver|O|C|R|R|R|R|R|R| Length | MD Type | Next Protocol | 348 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 349 Figure 2: NSH Base Header 351 Base Header Field Descriptions 353 Version: The version field is used to ensure backward compatibility 354 going forward with future NSH updates. 356 O bit: Indicates that this packet is an operations and management 357 (OAM) packet. SFF and SFs nodes MUST examine the payload and take 358 appropriate action (e.g. return status information). 360 OAM message specifics and handling details are outside the scope of 361 this document. 363 C bit: Indicates that a critical metadata TLV is present (see Section 364 3.4.2). This bit acts as an indication for hardware implementers to 365 decide how to handle the presence of a critical TLV without 366 necessarily needing to parse all TLVs present. The C bit MUST be set 367 to 1 if one or more critical TLVs are present. 369 All other flag fields are reserved. 371 Length: total length, in 4-byte words, of the NSH header, including 372 optional variable TLVs. 374 MD Type: indicates the format of NSH beyond the base header and the 375 type of metadata being carried. This typing is used to describe the 376 use for the metadata. A new registry will be requested from IANA for 377 the MD Type. 379 NSH defines two MD types: 381 0x1 which indicates that the format of the header includes fixed 382 length context headers. 384 0x2 which does not mandate any headers beyond the base header and 385 service path header, and may contain optional variable length context 386 information. 388 The format of the base header is invariant, and not described by MD 389 Type. 391 NSH implementations MUST support MD-Type 0x1, and SHOULD support MD- 392 Type 0x2. 394 Next Protocol: indicates the protocol type of the original packet. A 395 new IANA registry will be created for protocol type. 397 This draft defines the following Next Protocol values: 399 0x1 : IPv4 400 0x2 : IPv6 401 0x3 : Ethernet 403 3.3. Service Path Header 405 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 1 406 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 407 | Service Path ID | Service Index | 408 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 410 Service path ID (SPI): 24 bits 411 Service index (SI): 8 bits 413 Figure 3: NSH Service Path Header 415 Service Path Identifier (SPI): identifies a service path. 416 Participating nodes MUST use this identifier for path selection. An 417 administrator can use the service path value for reporting and 418 troubleshooting packets along a specific path. 420 Service Index (SI): provides location within the service path. 421 Service index MUST be decremented by service functions or proxy nodes 422 after performing required services. MAY be used in conjunction with 423 service path for path selection. Service Index is also valuable when 424 troubleshooting/reporting service paths. In addition to location 425 within a path, SI can be used for loop detection. 427 3.4. NSH MD-type 1 429 When the base header specifies MD Type 1, NSH defines four 4-byte 430 mandatory context headers, as per Figure 4. These headers must be 431 present and the format is opaque as depicted in Figure 5. 433 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 1 434 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 435 |Ver|O|C|R|R|R|R|R|R| Length | MD-type=0x1 | Next Protocol | 436 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 437 | Service Path ID | Service Index | 438 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 439 | Mandatory Context Header | 440 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 441 | Mandatory Context Header | 442 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 443 | Mandatory Context Header | 444 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 445 | Mandatory Context Header | 446 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 448 Figure 4: NSH MD-type=0x1 450 0 1 2 3 451 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 1 452 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 453 | Context data | 454 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 456 Figure 5: Context Header 458 3.4.1. Mandatory Context Header Allocation Guidelines 460 0 1 2 3 461 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 1 462 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 463 | Network Platform Context | 464 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 465 | Network Shared Context | 466 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 467 | Service Platform Context | 468 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 469 | Service Shared Context | 470 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 471 Figure 6: Context Data Significance 473 Figure 6, above, and the following examples of context header 474 allocation are guidelines that illustrate how various forms of 475 information can be carried and exchanged via NSH. 477 Network platform context: provides platform-specific metadata shared 478 between network nodes. Examples include (but are not limited to) 479 ingress port information, forwarding context and encapsulation type. 481 Network shared context: metadata relevant to any network node such as 482 the result of edge classification. For example, application 483 information, identity information or tenancy information can be 484 shared using this context header. 486 Service platform context: provides service platform specific metadata 487 shared between service functions. This context header is analogous 488 to the network platform context, enabling service platforms to 489 exchange platform-centric information such as an identifier used for 490 load balancing decisions. 492 Service shared context: metadata relevant to, and shared, between 493 service functions. As with the shared network context, 494 classification information such as application type can be conveyed 495 using this context. 497 The data center[dcalloc] and mobility[moballoc] context header 498 allocation drafts provide guidelines for the semantics of NSH fixed 499 context headers in each respective environment. 501 3.5. NSH MD-type 2 503 When the base header specifies MD Type 2, NSH defines variable length 504 only context headers. There may be zero or more of these headers as 505 per the length field. 507 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 1 508 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 509 |Ver|O|C|R|R|R|R|R|R| Length | MD-type=0x2 | Next Protocol | 510 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 511 | Service Path ID | Service Index | 512 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 513 | | 514 ~ Optional Variable Length Context Headers ~ 515 | | 516 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 517 Figure 7: NSH MD-type=0x2 519 3.5.1. Optional Variable Length Metadata 521 NSH MD Type 2 MAY contain optional variable length context headers. 522 The format of these headers is as described below. 524 0 1 2 3 525 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 1 526 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 527 | TLV Class | Type |R|R|R| Len | 528 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 529 | Variable Metadata | 530 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 532 Figure 8: Variable Context Headers 534 TLV Class: describes the scope of the "Type" field. In some cases, 535 the TLV Class will identify a specific vendor, in others, the TLV 536 Class will identify specific standards body allocated types. 538 Type: the specific type of information being carried, within the 539 scope of a given TLV Class. Value allocation is the responsibility 540 of the TLV Class owner. 542 The most significant bit of the Type field indicates whether the TLV 543 is mandatory for the receiver to understand/process. This 544 effectively allocates Type values 0 to 127 for non-critical options 545 and Type values 128 to 255 for critical options. Figure 7 below 546 illustrates the placement of the Critical bit within the Type field. 548 +-+-+-+-+-+-+-+-+ 549 |C| Type | 550 +-+-+-+-+-+-+-+-+ 552 Figure 9: Critical Bit Placement Within the TLV Type Field 554 Encoding the criticality of the TLV within the Type field is 555 consistent with IPv6 option types. 557 If a receiver receives an encapsulated packet containing a TLV with 558 the Critical bit set in the Type field and it does not understand how 559 to process the Type, it MUST drop the packet. Transit devices MUST 560 NOT drop packets based on the setting of this bit. 562 Reserved bits: three reserved bit are present for future use. The 563 reserved bits MUST be zero. 565 Length: Length of the variable metadata, in 4-byte words. 567 4. NSH Actions 569 Service header aware nodes - service classifiers, SFF, SF and NSH 570 proxies, have several possible header related actions: 572 1. Insert or remove service header: These actions can occur at the 573 start and end respectively of a service path. Packets are 574 classified, and if determined to require servicing, a service 575 header imposed. The last node in a service path, an SFF, removes 576 the NSH. A service classifier MUST insert an NSH. At the end of 577 a service function chain, the last node operating on the service 578 header MUST remove it. 580 A service function can re-classify data as required and that re- 581 classification might result in a new service path. In this case, 582 the SF acts as a logical classifier as well. When the logical 583 classifier performs re-classification that results in a change of 584 service path, it MUST remove the existing NSH and MUST impose a 585 new NSH with the base header reflecting the new path. 587 2. Select service path: The base header provides service chain 588 information and is used by SFFs to determine correct service path 589 selection. SFFs MUST use the base header for selecting the next 590 service in the service path. 592 3. Update a service header: NSH aware service functions MUST 593 decrement the service index. A service index = 0 indicates that 594 a packet MUST be dropped by the SFF performing NSH-based 595 forwarding. 597 Service functions MAY update context headers if new/updated 598 context is available. 600 If an NSH proxy (see Section 7) is in use (acting on behalf of a 601 non-NSH-aware service function for NSH actions), then the proxy 602 MUST update service index and MAY update contexts. When an NSH 603 proxy receives an NSH-encapsulated packet, it removes the NSH 604 before forwarding it to an NSH unaware SF. When it receives a 605 packet back from an NSH unaware SF, it re-encapsulates it with 606 the NSH, decrementing the service index. 608 4. Service policy selection: Service function instances derive 609 policy selection from the service header. Context shared in the 610 service header can provide a range of service-relevant 611 information such as traffic classification. Service functions 612 SHOULD use NSH to select local service policy. 614 Figure 10 maps each of the four actions above to the components in 615 the SFC architecture that can perform it. 617 +----------------+--------------------+-------+---------------+-------+ 618 | | Insert or remove |Select | Update a |Service| 619 | | service header |service|service header |Policy | 620 | +------+------+------+ path +---------------+Select-| 621 | |Insert|Remove|Remove| | Dec. |Update |ion | 622 | | | | and | |Service|Context| | 623 | Component | | |Insert| | Index |Header | | 624 +----------------+------+------+------+-------+-------+-------+-------+ 625 |Service Classif-| + | | | | | + | | 626 |ication Function| | | | | | | | 627 + -------------- + ---- + ---- + ---- + ----- + ----- + ----- + ----- + 628 |Service Function| | + | | + | | + | | 629 |Forwarder(SFF) | | | | | | | | 630 + -------------- + ---- + ---- + ---- + ----- + ----- + ----- + ----- + 631 |Service | | | | | + | + | + | 632 |Function (SF) | | | | | | | | 633 + -------------- + ---- + ---- + ---- + ----- + ----- + ----- + ----- + 634 |NSH Proxy | + | + | | | + | + | | 635 +----------------+------+------+------+-------+-------+-------+-------+ 637 Figure 10: NSH Action and Role Mapping 639 5. NSH Encapsulation 641 Once NSH is added to a packet, an outer encapsulation is used to 642 forward the original packet and the associated metadata to the start 643 of a service chain. The encapsulation serves two purposes: 645 1. Creates a topologically independent services plane. Packets are 646 forwarded to the required services without changing the 647 underlying network topology. 649 2. Transit network nodes simply forward the encapsulated packets as 650 is. 652 The service header is independent of the encapsulation used and is 653 encapsulated in existing transports. The presence of NSH is 654 indicated via protocol type or other indicator in the outer 655 encapsulation. 657 See Section 11 for NSH encapsulation examples. 659 6. NSH Usage 661 The NSH creates a dedicated service plane, that addresses many of the 662 limitations highlighted in Section 2.2. More specifically, NSH 663 enables: 665 1. Topological Independence: Service forwarding occurs within the 666 service plane, via a network overlay, the underlying network 667 topology does not require modification. Service functions have 668 one or more network locators (e.g. IP address) to receive/send 669 data within the service plane, the NSH contains an identifier 670 that is used to uniquely identify a service path and the services 671 within that path. 673 2. Service Chaining: NSH contains path identification information 674 needed to realize a service path. Furthermore, NSH provides the 675 ability to monitor and troubleshoot a service chain, end-to-end 676 via service-specific OAM messages. The NSH fields can be used by 677 administrators (via, for example a traffic analyzer) to verify 678 (account, ensure correct chaining, provide reports, etc.) the 679 path specifics of packets being forwarded along a service path. 681 3. Metadata Sharing: NSH provides a mechanism to carry shared 682 metadata between network devices and service function, and 683 between service functions. The semantics of the shared metadata 684 is communicated via a control plane to participating nodes. 685 Examples of metadata include classification information used for 686 policy enforcement and network context for forwarding post 687 service delivery. 689 4. Transport Agnostic: NSH is transport independent and is carried 690 in an overlay, over existing underlays. If an existing overlay 691 topology provides the required service path connectivity, that 692 existing overlay may be used. 694 7. NSH Proxy Nodes 696 In order to support NSH-unaware service functions, an NSH proxy is 697 used. The proxy node removes the NSH header and delivers the 698 original packet/frame via a local attachment circuit to the service 699 function. Examples of a local attachment circuit include, but are 700 not limited to: VLANs, IP in IP, GRE, VXLAN. When complete, the 701 service function returns the packet to the NSH proxy via the same or 702 different attachment circuit. 704 NSH is re-imposed on packets returned to the proxy from the non-NSH- 705 aware service. 707 Typically, an SFF will act as an NSH-proxy when required. 709 An NSH proxy MUST perform NSH actions as described in Section 4. 711 8. Fragmentation Considerations 713 Work in progress 715 9. Service Path Forwarding with NSH 717 9.1. SFFs and Overlay Selection 719 As described above, NSH contains a service path identifier (SPI) and 720 a service index (SI). The SPI is, as per its name, an identifier. 721 The SPI alone cannot be used to forward packets along a service path. 722 Rather the SPI provide a level of indirection between the service 723 path/topology and the network transport. Furthermore, there is no 724 requirement, or expectation of an SPI being bound to a pre-determined 725 or static network path. 727 The service index provides an indication of location within a service 728 path. The combination of SPI and SI provides the identification and 729 location of a logical SF (locator and order). The logical SF may be 730 a single SF, or a set of SFs that are equivalent. In the latter 731 case, the SFF provides load distribution amongst the collection of 732 SFs as needed. SI may also serve as a mechanism for loop detection 733 with in a service path since each SF in the path decrements the 734 index; an index of 0 indicates that a loop occurred and packet must 735 be discarded. 737 This indirection -- path ID to overlay -- creates a true service 738 plane. That is the SFF/SF topology is constructed without impacting 739 the network topology but more importantly service plane only 740 participants (i.e. most SFs) need not be part of the network overlay 741 topology and its associated infrastructure (e.g. control plane, 742 routing tables, etc.). As mentioned above, an existing overlay 743 topology may be used provided it offers the requisite connectivity. 745 The mapping of SPI to transport occurs on an SFF. The SFF consults 746 the SPI/ID values to determine the appropriate overlay transport 747 protocol (several may be used within a given network) and next hop 748 for the requisite SF. Figure 10 below depicts an SPI/SI to network 749 overlay mapping. 751 +-------------------------------------------------------+ 752 | SPI | SI | NH | Transport | 753 +-------------------------------------------------------+ 754 | 10 | 3 | 1.1.1.1 | VXLAN-gpe | 755 | 10 | 2 | 2.2.2.2 | nvGRE | 756 | 245 | 12 | 192.168.45.3 | VXLAN-gpe | 757 | 10 | 9 | 10.1.2.3 | GRE | 758 | 40 | 9 | 10.1.2.3 | GRE | 759 | 50 | 7 | 01:23:45:67:89:ab | Ethernet | 760 | 15 | 1 | Null (end of path) | None | 761 +-------------------------------------------------------+ 762 Figure 11: SFF NSH Mapping Example 764 Additionally, further indirection is possible: the resolution of the 765 required SF function locator may be a localized resolution on an 766 SFF,rather than a service function chain control plane 767 responsibility, as per figures 11 and 12 below. 769 +-------------------+ 770 | SPI | SI | NH | 771 +-------------------+ 772 | 10 | 3 | SF2 | 773 | 245 | 12 | SF34 | 774 | 40 | 9 | SF9 | 775 +-------------------+ 777 Figure 12: NSH to SF Mapping Example 779 +-----------------------------------+ 780 | SF | NH | Transport | 781 +-----------------------------------| 782 | SF2 | 10.1.1.1 | VXLAN-gpe | 783 | SF34| 192.168.1.1 | UDP | 784 | SF9 | 1.1.1.1 | GRE | 785 +-----------------------------------+ 787 Figure 13: SF Locator Mapping Example 789 Since the SPI is a representation of the service path, the lookup may 790 return more than one possible next-hop within a service path for a 791 given SF, essentially a series of weighted (equally or otherwise) 792 overlay links to be used (for load distribution, redundancy or 793 policy), see Figure 13. The metric depicted in Figure 13 is an 794 example to help illustrated weighing SFs. In a real network, the 795 metric will range from a simple preference (similar to routing next- 796 hop), to a true dynamic composite metric based on some service 797 function-centric state (including load, sessions sate, capacity, 798 etc.) 799 +----------------------------------+ 800 | SPI | SI | NH | Metric | 801 +----------------------------------+ 802 | 10 | 3 | 10.1.1.1 | 1 | 803 | | | 10.1.1.2 | 1 | 804 | | | | | 805 | 20 | 12 | 192.168.1.1 | 1 | 806 | | | 10.2.2.2 | 1 | 807 | | | | | 808 | 30 | 7 | 10.2.2.3 | 10 | 809 | | | 10.3.3.3 | 5 | 810 +----------------------------------+ 811 (encap type omitted for formatting) 813 Figure 14: NSH Weighted Service Path 815 9.2. Mapping NSH to Network Overlay 817 As described above, the mapping of SPI to network topology may result 818 in a single overlay path, or it might result in a more complex 819 topology. Furthermore, the SPIx to overlay mapping occurs at each 820 SFF independently. Any combination of topology selection is 821 possible. 823 Examples of mapping for a topology: 825 1. Next SF is located at SFFb with locator 10.1.1.1 826 SFFa mapping: SPI=10 --> VXLAN-gpe, dst-ip: 10.1.1.1 828 2. Next SF is located at SFFc with multiple locator for load 829 distribution purposes: 830 SFFb mapping: SPI=10 --> VXLAN-gpe, dst_ip:10.2.2.1, 10.2.2.2, 831 10.2.2.3, equal cost 833 3. Next SF is located at SFFd with two path to SFFc, one for 834 redundancy: 835 SFFc mapping: SPI=10 --> VXLAN-gpe, dst_ip:10.1.1.1 cost=10, 836 10.1.1.2, cost=20 838 In the above example, each SFF makes an independent decision about 839 the network overlay path and policy for that path. In other words, 840 there is no a priori mandate about how to forward packets in the 841 network (only the order of services that must be traversed). 843 The network operator retains the ability to engineer the overlay 844 paths as required. For example, the overlay path between service 845 functions forwarders may utilize traffic engineering, QoS marking, or 846 ECMP, without requiring complex configuration and network protocol 847 support to be extended to the service path explicitly. In other 848 words, the network operates as expected, and evolves as required, as 849 does the service function plane. 851 9.3. Service Plane Visibility 853 The SPI and SI serve an important function for visibility into the 854 service topology. An operator can determine what service path a 855 packet is "on", and its location within that path simply by viewing 856 the NSH information (packet capture, IPFIX, etc.). The information 857 can be used for service scheduling and placement decisions, 858 troubleshooting and compliance verification. 860 9.4. Service Graphs 862 In some cases, a service path is exactly that -- a linear list of 863 service functions that must be traversed. However, increasingly, the 864 "path" is actually a true directed graph. Furthermore, within a 865 given service topology several directed graphs may exist with packets 866 moving between graphs based on non-initial classification (usually 867 performed by a service function). Note: strictly speaking a path is 868 a form of graph; the intent is to distinguish between a directed 869 graph and a path. 871 ,---. ,---. ,---. 872 / \ / \ / \ 873 ( SF2 ) ( SF7 ) ( SF3 ) 874 ,------\ +. \ / \ / 875 ; |---' `-. `---'\ `-+-' 876 | : : \ ; 877 | \ | : ; 878 ,-+-. `. ,+--. : | 879 / \ '---+ \ \ ; 880 ( SF1 ) ( SF6 ) \ / 881 \ / \ +--. : / 882 `---' `---' `-. ,-+-. / 883 `+ +' 884 ( SF4 ) 885 \ / 886 `---' 888 Figure 15: Service Graph Example 890 The SPI/SI combination provides a simple representation of a directed 891 graph, the SPI represents a graph ID; and the SI a node ID. The 892 service topology formed by SPI/SI support cycles, weighting, and 893 alternate topology selection, all within the service plane. The 894 realization of the network topology occurs as described above: SPI/ID 895 mapping to an appropriate transport and associated next network hops. 897 NSH-aware services receive the entire header, including the SPI/SI. 898 An SF can now, based on local policy, alter the SPI, which in turn 899 effects both the service graph, and in turn the selection of overlay 900 at the SFF. The figure below depicts the policy associated with the 901 graph in Figure 14 above. Note: this illustrates multiple graphs and 902 their representation; it does not depict the use of metadata within a 903 single service function graph. 905 +---------------------------------------------------------------------+ 906 | SPI: 21 Bob: SF7 | 907 | SPI: 20 Bad : SF2 --> SF6 --> SF4 | 908 |SPI: 10 SF1 --> SF2 --> SF6 SPI: 22 Alice: SF3 | 909 | SPI: 30 Good: SF4 | 910 | SPI:31 Bob: SF7 | 911 | SPI:32 Alice: SF3 | 912 +---------------------------------------------------------------------+ 914 Figure 16: Service Graphs Using SPI 916 This example above does not show the mapping of the service topology 917 to the network overlay topology. As discussed in the sections above, 918 the overlay selection occurs as per network policy. 920 10. Policy Enforcement with NSH 922 10.1. NSH Metadata and Policy Enforcement 924 As described in Section 3, NSH provides the ability to carry metadata 925 along a service path. This metadata may be derived from several 926 sources, common examples include: 928 Network nodes: Information provided by network nodes can indicate 929 network-centric information (such as VRF or tenant) that may be 930 used by service functions, or conveyed to another network node 931 post-service pathing. 933 External (to the network) systems: External systems, such as 934 orchestration systems, often contain information that is valuable 935 for service function policy decisions. In most cases, this 936 information cannot be deduced by network nodes. For example, a 937 cloud orchestration platform placing workloads "knows" what 938 application is being instantiated and can communicate this 939 information to all NSH nodes via metadata. 941 Service functions: Service functions often perform very detailed 942 and valuable classification. In some cases they may terminate, 943 and be able to inspect encrypted traffic. SFs may update, alter 944 or impose metadata information. 946 Regardless of the source, metadata reflects the "result" of 947 classification. The granularity of classification may vary. For 948 example, a network switch might only be able to classify based on a 949 5-tuple, whereas, a service function may be able to inspect 950 application information. Regardless of granularity, the 951 classification information can be represented in NSH. 953 Once the data is added to NSH, it is carried along the service path, 954 NSH-aware SFs receive the metadata, and can use that metadata for 955 local decisions and policy enforcement. The following two examples 956 highlight the relationship between metadata and policy: 958 +-------------------------------------------------+ 959 | ,---. ,---. ,---. | 960 | / \ / \ / \ | 961 | ( SCL )-------->( SF1 )--------->( SF2 ) | 962 | \ / \ / \ / | 963 | `---' `---' `---' | 964 |5-tuple: Permit Inspect | 965 |Tenant A Tenant A AppY | 966 |AppY | 967 +-------------------------------------------------+ 969 Figure 17: Metadata and Policy 971 +-------------------------------------------------+ 972 | ,---. ,---. ,---. | 973 | / \ / \ / \ | 974 | ( SCL )-------->( SF1 )--------->( SF2 ) | 975 | \ / \ / \ / | 976 | `-+-' `---' `---' | 977 | | Permit Deny AppZ | 978 | +---+---+ employees | 979 | | | | 980 | +-------+ | 981 | external | 982 | system: | 983 | Employee | 984 | App Z | 985 +-------------------------------------------------+ 987 Figure 18: External Metadata and Policy 989 In both of the examples above, the service functions perform policy 990 decisions based on the result of the initial classification: the SFs 991 did not need to perform re-classification, rather they relied on a 992 antecedent classification for local policy enforcement. 994 10.2. Updating/Augmenting Metadata 996 Post-initial metadata imposition (typically performed during initial 997 service path determination), metadata may be augmented or updated: 999 1. Metadata Augmentation: Information may be added to NSH's existing 1000 metadata, as depicted in Figure 18. For example, if the initial 1001 classification returns the tenant information, a secondary 1002 classification (perhaps a DPI or SLB) may augment the tenant 1003 classification with application information. The tenant 1004 classification is still valid and present, but additional 1005 information has been added to it. 1007 2. Metadata Update: Subsequent classifiers may update the initial 1008 classification if it is determined to be incorrect or not 1009 descriptive enough. For example, the initial classifier adds 1010 metadata that describes the trafic as "internet" but a security 1011 service function determines that the traffic is really "attack". 1012 Figure 19 illustrates an example of updating metadata. 1014 +-------------------------------------------------+ 1015 | ,---. ,---. ,---. | 1016 | / \ / \ / \ | 1017 | ( SCL )-------->( SF1 )--------->( SF2 ) | 1018 | \ / \ / \ / | 1019 | `-+-' `---' `---' | 1020 | | Inspect Deny | 1021 | +---+---+ employees employee+ | 1022 | | | Class=AppZ appZ | 1023 | +-------+ | 1024 | external | 1025 | system: | 1026 | Employee | 1027 | | 1028 +-------------------------------------------------+ 1030 Figure 19: Metadata Augmentation 1032 +-------------------------------------------------+ 1033 | ,---. ,---. ,---. | 1034 | / \ / \ / \ | 1035 | ( SCL )-------->( SF1 )--------->( SF2 ) | 1036 | \ / \ / \ / | 1037 | `---' `---' `---' | 1038 |5-tuple: Inspect Deny | 1039 |Tenant A Tenant A attack | 1040 | --> attack | 1041 +-------------------------------------------------+ 1043 Figure 20: Metadata Update 1045 10.3. Service Path ID and Metadata 1047 Metadata information may influence the service path selection since 1048 the service path identifier can represent the result of 1049 classification. A given SPI can represent all or some of the 1050 metadata, and be updated based on metadata classification results. 1051 This relationship provides the ability to create a dynamic services 1052 plane based on complex classification without requiring each node to 1053 be capable of such classification, or requiring a coupling to the 1054 network topology. This yields service graph functionality as 1055 described in Section 9.4. Figure 20 illustrates an example of this 1056 behavior. 1058 +----------------------------------------------------+ 1059 | ,---. ,---. ,---. | 1060 | / \ / \ / \ | 1061 | ( SCL )-------->( SF1 )--------->( SF2 ) | 1062 | \ / \ / \ / | 1063 | `---' `---' \ `---' | 1064 |5-tuple: Inspect \ Original | 1065 |Tenant A Tenant A \ next SF | 1066 | --> DoS \ | 1067 | \ | 1068 | ,---. | 1069 | / \ | 1070 | ( SF10 ) | 1071 | \ / | 1072 | `---' | 1073 | DoS | 1074 | "Scrubber" | 1075 +----------------------------------------------------+ 1077 Figure 21: Path ID and Metadata 1079 Specific algorithms for mapping metadata to an SPI are outside the 1080 scope of this draft. 1082 11. NSH Encapsulation Examples 1084 11.1. GRE + NSH 1086 IPv4 Packet: 1087 +----------+--------------------+--------------------+ 1088 |L2 header | L3 header, proto=47|GRE header,PT=0x894F| 1089 +----------+--------------------+--------------------+ 1090 --------------+----------------+ 1091 NSH, NP=0x1 |original packet | 1092 --------------+----------------+ 1094 L2 Frame: 1095 +----------+--------------------+--------------------+ 1096 |L2 header | L3 header, proto=47|GRE header,PT=0x894F| 1097 +----------+--------------------+--------------------+ 1098 ---------------+---------------+ 1099 NSH, NP=0x3 |original frame | 1100 ---------------+---------------+ 1102 Figure 22: GRE + NSH 1104 11.2. VXLAN-gpe + NSH 1106 IPv4 Packet: 1107 +----------+------------------------+---------------------+ 1108 |L2 header | IP + UDP dst port=4790 |VXLAN-gpe NP=0x4(NSH)| 1109 +----------+------------------------+---------------------+ 1110 --------------+----------------+ 1111 NSH, NP=0x1 |original packet | 1112 --------------+----------------+ 1114 L2 Frame: 1115 +----------+------------------------+---------------------+ 1116 |L2 header | IP + UDP dst port=4790 |VXLAN-gpe NP=0x4(NSH)| 1117 +----------+------------------------+---------------------+ 1118 ---------------+---------------+ 1119 NSH,NP=0x3 |original frame | 1120 ---------------+---------------+ 1122 Figure 23: VXLAN-gpe + NSH 1124 11.3. Ethernet + NSH 1126 IPv4 Packet: 1127 +-------------------------------+---------------+--------------------+ 1128 |Outer Ethernet, ET=0x894F | NSH, NP = 0x1 | original IP Packet | 1129 +-------------------------------+---------------+--------------------+ 1131 L2 Frame: 1132 +-------------------------------+---------------+----------------+ 1133 |Outer Ethernet, ET=0x894F | NSH, NP = 0x3 | original frame | 1134 +-------------------------------+---------------+----------------+ 1136 Figure 24: Ethernet + NSH 1138 12. Security Considerations 1140 As with many other protocols, NSH data can be spoofed or otherwise 1141 modified. In many deployments, NSH will be used in a controlled 1142 environment, with trusted devices (e.g. a data center) thus 1143 mitigating the risk of unauthorized header manipulation. 1145 NSH is always encapsulated in a transport protocol and therefore, 1146 when required, existing security protocols that provide authenticity 1147 (e.g. RFC 2119 [RFC6071]) can be used. 1149 Similarly if confidentiality is required, existing encryption 1150 protocols can be used in conjunction with encapsulated NSH. 1152 13. Open Items for WG Discussion 1154 1. MD type 1 metadata semantics specifics 1156 2. Bypass bit in NSH. 1158 3. Rendered Service Path ID (RSPID). 1160 14. Contributors 1162 The following people are active contributors to this document and 1163 have provided review, content and concepts (listed alphabetically by 1164 surname): 1166 Andrew Dolganow 1167 Alcaltel-Lucent 1168 Email: andrew.dolganow@alcatel-lucent.com 1170 Rex Fernando 1171 Cisco Systems 1172 Email: rex@cisco.com 1174 Praveen Muley 1175 Alcaltel-Lucent 1176 Email: praveen.muley@alcatel-lucent.com 1178 Navindra Yadav 1179 Cisco Systems 1180 Email: nyadav@cisco.com 1182 15. Acknowledgments 1184 The authors would like to thank Nagaraj Bagepalli, Abhijit Patra, Ron 1185 Parker, Peter Bosch, Darrel Lewis, Pritesh Kothari, Tal Mizrahi and 1186 Ken Gray for their detailed review, comments and contributions. 1188 A special thank you goes to David Ward and Tom Edsall for their 1189 guidance and feedback. 1191 Additionally the authors would like to thank Carlos Pignataro and 1192 Larry Kreeger for their invaluable ideas and contributions which are 1193 reflected throughout this draft. 1195 16. IANA Considerations 1197 16.1. NSH EtherType 1199 An IEEE EtherType, 0x894F, has been allocated for NSH. 1201 16.2. Network Service Header (NSH) Parameters 1203 IANA is requested to create a new "Network Service Header (NSH) 1204 Parameters" registry. The following sub-sections request new 1205 registries within the "Network Service Header (NSH) Parameters " 1206 registry. 1208 16.2.1. NSH Base Header Reserved Bits 1210 There are ten bits at the beginning of the NSH Base Header. New bits 1211 are assigned via Standards Action [RFC5226]. 1213 Bits 0-1 - Version 1214 Bit 2 - OAM (O bit) 1215 Bits 2-9 - Reserved 1217 16.2.2. MD Type Registry 1219 IANA is requested to set up a registry of "MD Types". These are 1220 8-bit values. MD Type values 0, 1, 2, 254, and 255 are specified in 1221 this document. Registry entries are assigned by using the "IETF 1222 Review" policy defined in RFC 5226 [RFC5226]. 1224 +---------+--------------+---------------+ 1225 | MD Type | Description | Reference | 1226 +---------+--------------+---------------+ 1227 | 0 | Reserved | This document | 1228 | | | | 1229 | 1 | NSH | This document | 1230 | | | | 1231 | 2 | NSH | This document | 1232 | | | | 1233 | 3..253 | Unassigned | | 1234 | | | | 1235 | 254 | Experiment 1 | This document | 1236 | | | | 1237 | 255 | Experiment 2 | This document | 1238 +---------+--------------+---------------+ 1240 Table 1 1242 16.2.3. TLV Class Registry 1244 IANA is requested to set up a registry of "TLV Types". These are 16- 1245 bit values. Registry entries are assigned by using the "IETF Review" 1246 policy defined in RFC 5226 [RFC5226]. 1248 16.2.4. NSH Base Header Next Protocol 1250 IANA is requested to set up a registry of "Next Protocol". These are 1251 8-bit values. Next Protocol values 0, 1, 2 and 3 are defined in this 1252 draft. New values are assigned via Standards Action [RFC5226]. 1254 +---------------+-------------+---------------+ 1255 | Next Protocol | Description | Reference | 1256 +---------------+-------------+---------------+ 1257 | 0 | Reserved | This document | 1258 | | | | 1259 | 1 | IPv4 | This document | 1260 | | | | 1261 | 2 | IPv6 | This document | 1262 | | | | 1263 | 3 | Ethernet | This document | 1264 | | | | 1265 | 4..253 | Unassigned | | 1266 +---------------+-------------+---------------+ 1268 Table 2 1270 17. References 1272 17.1. Normative References 1274 [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, 1275 September 1981. 1277 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1278 Requirement Levels", BCP 14, RFC 2119, March 1997. 1280 17.2. Informative References 1282 [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. 1283 Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, 1284 March 2000. 1286 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1287 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 1288 May 2008. 1290 [RFC6071] Frankel, S. and S. Krishnan, "IP Security (IPsec) and 1291 Internet Key Exchange (IKE) Document Roadmap", RFC 6071, 1292 February 2011. 1294 [SFC-PS] Quinn, P., Ed. and T. Nadeau, Ed., "Service Function 1295 Chaining Problem Statement", 2014, . 1299 [SFC-arch] 1300 Quinn, P., Ed. and J. Halpern, Ed., "Service Function 1301 Chaining (SFC) Architecture", 2014, 1302 . 1304 [VXLAN-gpe] 1305 Quinn, P., Agarwal, P., Kreeger, L., Lewis, D., Maino, F., 1306 Yong, L., Xu, X., Elzur, U., and P. Garg, "Generic 1307 Protocol Extension for VXLAN", 1308 . 1310 [dcalloc] Guichard, J., Smith, M., and S. Kumar, "Network Service 1311 Header (NSH) Context Header Allocation (Data Center)", 1312 2014, . 1315 [moballoc] 1316 Napper, J. and S. Kumar, "NSH Context Header Allocation -- 1317 Mobility", 2014, . 1320 Authors' Addresses 1322 Paul Quinn 1323 Cisco Systems, Inc. 1325 Email: paulq@cisco.com 1327 Jim Guichard 1328 Cisco Systems, Inc. 1330 Email: jguichar@cisco.com 1332 Surendra Kumar 1333 Cisco Systems, Inc. 1335 Email: smkumar@cisco.com 1337 Michael Smith 1338 Cisco Systems, Inc. 1340 Email: michsmit@cisco.com 1342 Wim Henderickx 1343 Alcatel-Lucent 1345 Email: wim.henderickx@alcatel-lucent.com 1347 Tom Nadeau 1348 Brocade 1350 Email: tnadeau@lucidvision.com 1352 Puneet Agarwal 1354 Email: puneet@acm.org 1356 Rajeev Manur 1357 Broadcom 1359 Email: rmanur@broadcom.com 1360 Abhishek Chauhan 1361 Citrix 1363 Email: Abhishek.Chauhan@citrix.com 1365 Joel Halpern 1366 Ericsson 1368 Email: joel.halpern@ericsson.com 1370 Sumandra Majee 1371 F5 1373 Email: S.Majee@F5.com 1375 Uri Elzur 1376 Intel 1378 Email: uri.elzur@intel.com 1380 David Melman 1381 Marvell 1383 Email: davidme@marvell.com 1385 Pankaj Garg 1386 Microsoft 1388 Email: Garg.Pankaj@microsoft.com 1390 Brad McConnell 1391 Rackspace 1393 Email: bmcconne@rackspace.com 1395 Chris Wright 1396 Red Hat Inc. 1398 Email: chrisw@redhat.com 1399 Kevin Glavin 1400 Riverbed 1402 Email: kevin.glavin@riverbed.com 1404 Hong (Cathy) Zhang 1405 Huawei US R&D 1407 Email: cathy.h.zhang@huawei.com 1409 Louis Fourie 1410 Huawei US R&D 1412 Email: louis.fourie@huawei.com 1414 Ron Parker 1415 Affirmed Networks 1417 Email: ron_parker@affirmednetworks.com 1419 Myo Zarny 1420 Goldman Sachs 1422 Email: myo.zarny@gs.com