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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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-29) exists of draft-ietf-pcp-base-09 ** Obsolete normative reference: RFC 3315 (Obsoleted by RFC 8415) == Outdated reference: A later version (-10) exists of draft-ietf-behave-lsn-requirements-01 == Outdated reference: A later version (-11) exists of draft-ietf-softwire-dual-stack-lite-07 Summary: 1 error (**), 0 flaws (~~), 4 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 PCP Working Group M. Boucadair 3 Internet-Draft France Telecom 4 Intended status: Standards Track R. Penno 5 Expires: October 29, 2011 Juniper Networks 6 D. Wing 7 Cisco 8 April 27, 2011 10 DHCP and DHCPv6 Options for the Port Control Protocol (PCP) 11 draft-bpw-pcp-dhcp-04 13 Abstract 15 This document specifies DHCP (IPv4 and IPv6) options to configure 16 hosts with Port Control Protocol (PCP) Server addresses. The use of 17 IPv4 DHCP or DHCPv6 depends on the PCP deployment scenario. 19 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 October 29, 2011. 42 Copyright Notice 44 Copyright (c) 2011 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. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 60 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 61 3. Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . 3 62 4. Consistent NAT and PCP Configuration . . . . . . . . . . . . . 4 63 5. DHCPv6 PCP Server Option . . . . . . . . . . . . . . . . . . . 5 64 5.1. Format . . . . . . . . . . . . . . . . . . . . . . . . . . 5 65 5.2. Client Behaviour . . . . . . . . . . . . . . . . . . . . . 5 66 5.3. Server Behaviour . . . . . . . . . . . . . . . . . . . . . 6 67 6. IPv4 DHCP PCP Option . . . . . . . . . . . . . . . . . . . . . 6 68 6.1. Format . . . . . . . . . . . . . . . . . . . . . . . . . . 6 69 6.2. Server Behaviour . . . . . . . . . . . . . . . . . . . . . 8 70 6.3. Client Behaviour . . . . . . . . . . . . . . . . . . . . . 8 71 7. Dual-Stack Hosts . . . . . . . . . . . . . . . . . . . . . . . 9 72 8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 73 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 74 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10 75 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 76 11.1. Normative References . . . . . . . . . . . . . . . . . . . 10 77 11.2. Informative References . . . . . . . . . . . . . . . . . . 10 78 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 80 1. Introduction 82 This document defines IPv4 DHCP [RFC2131] and DHCPv6 [RFC3315] 83 options which can be used to provision PCP Server [I-D.ietf-pcp-base] 84 reachability information; more precisely it defines DHCP options to 85 convey a Fully Qualified Domain Name (FQDN, as per Section 3.1 of 86 [RFC1035]) of PCP Server(s). In order to make use of these options, 87 this document assumes appropriate name resolution means (see Section 88 6.1.1 of [RFC1123]) are available on the host client. 90 The use of IPv4 DHCP or DHCPv6 depends on the PCP deployment 91 scenarios. 93 2. Terminology 95 This document makes use of the following terms: 97 o PCP Server: A functional element which receives and processes PCP 98 requests from a PCP Client. A PCP Server can be co-located with 99 or be separated from the function (e.g., NAT, Firewall) it 100 controls. Refer to [I-D.ietf-pcp-base]. 102 o PCP Client: a PCP software instance responsible for issuing PCP 103 requests to a PCP Server. Refer to [I-D.ietf-pcp-base]. 105 o DHCP refers to both IPv4 DHCP [RFC2131] and DHCPv6 [RFC3315]. 107 o DHCP client (or client) denotes a node that initiates requests to 108 obtain configuration parameters from one or more DHCP servers 109 [RFC3315]. 111 o DHCP server (or server) refers to a node that responds to requests 112 from DHCP clients [RFC3315]. 114 3. Rationale 116 Both IP Address and Name DHCP options have been defined in previous 117 versions of this document. This flexibility aims to let service 118 providers to make their own engineering choices and use the 119 convenient option according to their deployment context. 120 Nevertheless, DHC WG's position is this flexibility have some 121 drawbacks such as inducing errors. Therefore, only the Name option 122 is maintained within this document. 124 This choice of defining the PCP Name option rather than the IP 125 address is motivated by operational considerations: In particular, 126 some Service Providers are considering two levels of redirection: (1) 127 The first level is national-wise is undertaken by DHCP: a regional- 128 specific FQDN will be returned; (2) The second level is done during 129 the resolution of the regional-specific FQDN to redirect the customer 130 to a regional PCP Servers among a pool deployed regionally. Distinct 131 operational teams are responsible for each of the above mentioned 132 levels. A clear separation between the functional perimeter of each 133 team is a sensitive task for the maintenance of the offered services. 134 Regional teams will require to introduce new resources (e.g., new 135 PCP-controlled devices such as Carrier Grade NATs (CGNs, 136 [I-D.ietf-behave-lsn-requirements])) to meet an increase of customer 137 base. Operations related to the introduction of these new devices 138 (e.g., addressing, redirection, etc.) are implemented locally. 139 Having this regional separation provides flexibility to manage 140 portions of network operated by dedicated teams. This two-level 141 redirection can not be met by the IP Address option. 143 In addition to the operational considerations: 145 o The use of the FQDN for NAT64 146 [I-D.ietf-behave-v6v4-xlate-stateful] might be suitable for load- 147 balancing purposes; 149 o For the DS-Lite case [I-D.ietf-softwire-dual-stack-lite], if the 150 encapsulation mode is used to send PCP messages, an IP address may 151 be used since the AFTR selection is already done via the AFTR_NAME 152 DHCPv6 option [I-D.ietf-softwire-ds-lite-tunnel-option]. Of 153 course, this assumes that the PCP Server is co-located with the 154 AFTR function. If these functions are not co-located, conveying 155 the FQDN would be more convenient. 157 If the PCP Server is located in a LAN, a simple FQDN such as "pcp- 158 server.local" can be used. 160 4. Consistent NAT and PCP Configuration 162 The PCP Server discovered through DHCP must be able to install 163 mappings on the appropriate upstream PCP-controlled device that will 164 be crossed by packets transmitted by the host or any terminal 165 belonging to the same realm (e.g., DHCP client is embedded in a CP 166 router). In case this prerequisite is not met, customers would 167 experience service troubles and their service(s) won't be delivered 168 appropriately. 170 Note that this constraint is implicitly met in scenarios where only 171 one single PCP-controlled device is deployed in the network. 173 5. DHCPv6 PCP Server Option 175 This DHCPv6 option conveys a domain name to be used to retrieve the 176 IP addresses of PCP Server(s). Appropriate name resolution queries 177 should be issued to resolve the conveyed name. For instance, in the 178 context of a DS-Lite architecture 179 [I-D.ietf-softwire-dual-stack-lite], the retrieved address may be an 180 IPv4 address or an IPv4-mapped IPv6 address [RFC4291], and in the 181 case of NAT64 [I-D.ietf-behave-v6v4-xlate-stateful] an IPv6 address 182 can be retrieved. 184 5.1. Format 186 The format of the DHCPv6 PCP Server option is shown in Figure 1. 188 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 1 189 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 190 | OPTION_PCP_SERVER | Option-length | 191 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 192 | | 193 : PCP Server Domain Name : 194 | | 195 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 197 Figure 1: PCP Server FQDN DHCPv6 Option 199 The fields of the option shown in Figure 1 are as follows: 201 o Option-code: OPTION_PCP_SERVER (TBA, see Section 9) 203 o Option-length: Length of the 'PCP Server Domain Name' field in 204 octets. 206 o PCP Server Domain Name: The domain name of the PCP Server to be 207 used by the PCP Client. The domain name is encoded as specified 208 in Section 8 of [RFC3315]. Any possible future updates to Section 209 8 of the Section 8 of [RFC3315] also apply to this option. 211 5.2. Client Behaviour 213 To discover a PCP Server [I-D.ietf-pcp-base], the DHCPv6 client MUST 214 include an Option Request Option (ORO) requesting the DHCPv6 PCP 215 Server Name option as described in Section 22.7 of [RFC3315] (i.e., 216 include OPTION_PCP_SERVER on its OPTION_ORO). A client MAY also 217 include the OPTION_DNS_SERVERS option on its OPTION_ORO to retrieve a 218 DNS servers list. 220 If the DHCPv6 client receives more than one OPTION_PCP_SERVER option 221 from the DHCPv6 server, only the first instance of that option MUST 222 be used. 224 Upon receipt of an OPTION_PCP_SERVER option, the DHCPv6 client MUST 225 verify that the option length does not exceed 255 octets [RFC1035]). 226 The DHCPv6 client MUST verify the FQDN is a properly encoded as 227 detailed in Section 8 of [RFC3315]. 229 Once the FQDN conveyed in a OPTION_PCP_SERVER option is validated, 230 the included Name is passed to the name resolution library (see 231 Section 6.1.1 of [RFC1123] or [RFC6055]) to retrieve the 232 corresponding IP address (IPv4 or IPv6). If more than one IPv6/IPv4 233 address are retrieved, the PCP Client MUST use the procedure defined 234 in [I-D.ietf-pcp-base] for address selection. 236 It is RECOMMENDED to associate a TTL with any address resulting from 237 resolving the Name conveyed in a OPTION_PCP_SERVER DHCPv6 option when 238 stored in a local cache. Considerations on how to flush out a local 239 cache are out of the scope of this document. 241 5.3. Server Behaviour 243 A DHCPv6 server MUST NOT reply with a value for the OPTION_PCP_SERVER 244 if the DHCPv6 client has not explicitly included OPTION_PCP_SERVER in 245 its OPTION_ORO. 247 If OPTION_PCP_SERVER option is requested by the DHCPv6 client, the 248 DHCPv6 server MUST NOT send more than one OPTION_PCP_SERVER option in 249 the response. The DHCPv6 server MUST include only one FQDN in a 250 OPTION_PCP_SERVER option. The DHCPv6 server MUST NOT include an FQDN 251 having a length exceeding 255 octets. 253 6. IPv4 DHCP PCP Option 255 6.1. Format 257 The PCP Server IPv4 DHCP option can be used to configure a FQDN to be 258 used by the PCP Client to contact a PCP Server. The generic format 259 of this option is illustrated in Figure 2. 261 Because of the depletion of IPv4 DHCP option codes and in order to 262 anticipate future PCP-related IPv4 DHCP options, the proposed option 263 uses a sub-option field. 265 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 1 266 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 267 | Code | Length | 268 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 269 | | 270 : Sub-option 1 : 271 | | 272 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 273 | | 274 : ... : 275 | | 276 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 277 | | 278 : Sub-option n : 279 | | 280 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 282 Figure 2: IPv4 DHCP PCP Option 284 The description of the fields is as follows: 286 o Code: OPTION_PCP_SERVER (TBA, see Section 9); 288 o Length: Includes the length of included sub-options in octets; The 289 maximum length is 255 octets. 291 o One or several sub-options can be included in a PCP IPv4 DHCP 292 option. The format of each sub-option follows the structure shown 293 in Figure 3. 295 Sub-option 296 Code Len Data 297 +-----+-----+-----...---+ 298 | code| n | Data | 299 +-----+-----+-----...---+ 301 Figure 3: PCP Server sub-option 303 Only one sub-option is defined in this document: 305 1: PCP Server Domain Name Sub-option (OPTION_PCP_SERVER_D 306 (Figure 4)). This sub-option includes an FQDN of the PCP Server 307 to be used by the PCP Client when issuing PCP messages. 309 Sub-option 310 Code Len FQDN of PCP Server 311 +-----+-----+-----+-----+-----+-----+-----+-- 312 | 1 | n | s1 | s2 | s3 | s4 | s5 | ... 313 +-----+-----+-----+-----+-----+-----+-----+-- 315 Figure 4: PCP Server FQDN DHCP Sub-option 317 The fields of the PCP Server Domain Name sub-option shown in Figure 4 318 are: 320 o Sub-option Code: 1. 322 o Len: Length of the "PCP Server Domain Name" field in octets. 324 o PCP Server Domain Name: The domain name of the PCP Server to be 325 used by the PCP Client. The encoding of the domain name is 326 described in Section 3.1 of [RFC1035]. 328 A side effect of having the sub-option format is the risk to have a 329 large option exceeding the maximum permissible within a single option 330 (254 octets + the length octets). In such case, it is RECOMMENDED to 331 use [RFC3396]. 333 6.2. Server Behaviour 335 IPv4 DHCP server MUST NOT provide this option, unless the client 336 requested it in Parameter Request List Option. 338 If OPTION_PCP_SERVER option is requested by the IPv4 DHCP client, the 339 IPv4 DHCP server MUST NOT send more than one OPTION_PCP_SERVER option 340 and more than one OPTION_PCP_SERVER_D sub-option in the response. 341 The IPv4 DHCP server MUST include only one FQDN in a 342 OPTION_PCP_SERVER_D sub-option. 344 6.3. Client Behaviour 346 IPv4 DHCP client expresses the intent to get OPTION_PCP_SERVER by 347 specifying it in Parameter Request List Option [RFC2132]. 349 If the IPv4 DHCP client receives more than one OPTION_PCP_SERVER 350 option from the IPv4 DHCP server, only the first instance of that 351 option MUST be used. If the selected OPTION_PCP_SERVER includes more 352 than one OPTION_PCP_SERVER_D sub-option, only the first instance of 353 that option MUST be used. 355 When the PCP Server Domain Name Sub-option is used, the client 356 invokes the underlying name resolution library (see Section 6.1.1 of 357 [RFC1123] or [RFC6055]) to retrieve the IPv4 address(es) of the PCP 358 server(s). 360 7. Dual-Stack Hosts 362 A PCP Server configured using OPTION_PCP_SERVER over IPv4 DHCP is 363 likely to be resolved to IPv4 address(es). 365 A PCP Server configured using OPTION_PCP_SERVER over DHCPv6 may be 366 resolved to IPv4 address(es) (e.g., DS-Lite 367 [I-D.ietf-softwire-dual-stack-lite]) or IPv6 address(es) (e.g., NAT64 368 [I-D.ietf-behave-v6v4-xlate-stateful], IPv6 firewall [RFC6092], NPTv6 369 [I-D.mrw-nat66]). 371 In some deployment contexts, the PCP Server may be reachable with an 372 IPv4 address but DHCPv6 is used to provision the PCP Client. In such 373 scenarios, a plain IPv4 address or an IPv4-mapped IPv6 address can be 374 configured to reach the PCP Server. 376 A Dual-Stack host may receive OPTION_PCP_SERVER via both IPv4 DHCP 377 and DHCPv6. The content of these OPTION_PCP_SERVER options may refer 378 to the same or distinct PCP Servers. This is deployment-specific and 379 as such it is out of scope of this document. 381 8. Security Considerations 383 The security considerations in [RFC2131], [RFC3315] and 384 [I-D.ietf-pcp-base] are to be considered. 386 9. IANA Considerations 388 Authors of this document request the following DHCPv6 option code: 390 OPTION_PCP_SERVER 392 Authors of this document request the following IPv4 DHCP option code: 394 OPTION_PCP_SERVER 396 Authors of this document request also to create a sub-option registry 397 for OPTION_PCP_SERVER option; a code for the following sub-option is 398 requested: 400 OPTION_PCP_SERVER_D 402 10. Acknowledgements 404 Many thanks to B. Volz, C. Jacquenet, R. Maglione, D. Thaler and T. 405 Mrugalski for their review and comments. 407 11. References 409 11.1. Normative References 411 [I-D.ietf-pcp-base] 412 Wing, D., Cheshire, S., Boucadair, M., and R. Penno, "Port 413 Control Protocol (PCP)", draft-ietf-pcp-base-09 (work in 414 progress), April 2011. 416 [RFC1035] Mockapetris, P., "Domain names - implementation and 417 specification", STD 13, RFC 1035, November 1987. 419 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 420 Requirement Levels", BCP 14, RFC 2119, March 1997. 422 [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", 423 RFC 2131, March 1997. 425 [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor 426 Extensions", RFC 2132, March 1997. 428 [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., 429 and M. Carney, "Dynamic Host Configuration Protocol for 430 IPv6 (DHCPv6)", RFC 3315, July 2003. 432 [RFC3396] Lemon, T. and S. Cheshire, "Encoding Long Options in the 433 Dynamic Host Configuration Protocol (DHCPv4)", RFC 3396, 434 November 2002. 436 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 437 Architecture", RFC 4291, February 2006. 439 11.2. Informative References 441 [I-D.ietf-behave-lsn-requirements] 442 Perreault, S., Yamagata, I., Miyakawa, S., Nakagawa, A., 443 and H. Ashida, "Common requirements for IP address sharing 444 schemes", draft-ietf-behave-lsn-requirements-01 (work in 445 progress), March 2011. 447 [I-D.ietf-behave-v6v4-xlate-stateful] 448 Bagnulo, M., Matthews, P., and I. Beijnum, "Stateful 449 NAT64: Network Address and Protocol Translation from IPv6 450 Clients to IPv4 Servers", 451 draft-ietf-behave-v6v4-xlate-stateful-12 (work in 452 progress), July 2010. 454 [I-D.ietf-softwire-ds-lite-tunnel-option] 455 Hankins, D. and T. Mrugalski, "Dynamic Host Configuration 456 Protocol for IPv6 (DHCPv6) Option for Dual- Stack Lite", 457 draft-ietf-softwire-ds-lite-tunnel-option-10 (work in 458 progress), March 2011. 460 [I-D.ietf-softwire-dual-stack-lite] 461 Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- 462 Stack Lite Broadband Deployments Following IPv4 463 Exhaustion", draft-ietf-softwire-dual-stack-lite-07 (work 464 in progress), March 2011. 466 [I-D.mrw-nat66] 467 Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix 468 Translation", draft-mrw-nat66-16 (work in progress), 469 April 2011. 471 [RFC1123] Braden, R., "Requirements for Internet Hosts - Application 472 and Support", STD 3, RFC 1123, October 1989. 474 [RFC6055] Thaler, D., Klensin, J., and S. Cheshire, "IAB Thoughts on 475 Encodings for Internationalized Domain Names", RFC 6055, 476 February 2011. 478 [RFC6092] Woodyatt, J., "Recommended Simple Security Capabilities in 479 Customer Premises Equipment (CPE) for Providing 480 Residential IPv6 Internet Service", RFC 6092, 481 January 2011. 483 Authors' Addresses 485 Mohamed Boucadair 486 France Telecom 487 Rennes, 35000 488 France 490 Email: mohamed.boucadair@orange-ftgroup.com 491 Reinaldo Penno 492 Juniper Networks 493 1194 N Mathilda Avenue 494 Sunnyvale, California 94089 495 USA 497 Email: rpenno@juniper.net 499 Dan Wing 500 Cisco Systems, Inc. 501 170 West Tasman Drive 502 San Jose, California 95134 503 USA 505 Email: dwing@cisco.com