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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group R. Bush 3 Internet-Draft Internet Initiative Japan 4 Intended status: Best Current Practice June 6, 2016 5 Expires: December 8, 2016 7 BGPsec Operational Considerations 8 draft-ietf-sidr-bgpsec-ops-08 10 Abstract 12 Deployment of the BGPsec architecture and protocols has many 13 operational considerations. This document attempts to collect and 14 present the most critical and universal. It is expected to evolve as 15 BGPsec is formalized and initially deployed. 17 Requirements Language 19 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 20 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to 21 be interpreted as described in RFC 2119 [RFC2119] only when they 22 appear in all upper case. They may also appear in lower or mixed 23 case as English words, without normative meaning. 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 December 8, 2016. 42 Copyright Notice 44 Copyright (c) 2016 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 . . . . . . . . . . . . . . . . . . . . . . . . 2 60 2. Suggested Reading . . . . . . . . . . . . . . . . . . . . . . 3 61 3. RPKI Distribution and Maintenance . . . . . . . . . . . . . . 3 62 4. AS/Router Certificates . . . . . . . . . . . . . . . . . . . 3 63 5. Within a Network . . . . . . . . . . . . . . . . . . . . . . 3 64 6. Considerations for Edge Sites . . . . . . . . . . . . . . . . 4 65 7. Routing Policy . . . . . . . . . . . . . . . . . . . . . . . 4 66 8. Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 67 9. Security Considerations . . . . . . . . . . . . . . . . . . . 7 68 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 69 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7 70 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 71 12.1. Normative References . . . . . . . . . . . . . . . . . . 7 72 12.2. Informative References . . . . . . . . . . . . . . . . . 8 73 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8 75 1. Introduction 77 BGPsec, [I-D.ietf-sidr-bgpsec-overview], is a new protocol with many 78 operational considerations. It is expected to be deployed 79 incrementally over a number of years. As core BGPsec-capable routers 80 may require large memory and/or modern CPUs, it is thought that 81 origin validation based on the RPKI, [RFC6811], will occur over the 82 next twp to three years and that BGPsec will start to deploy well 83 after that. 85 BGPsec relies on widespread propagation of the Resource Public Key 86 Infrastructure (RPKI) [RFC6480]. How the RPKI is distributed and 87 maintained globally and within an operator's infrastructure may be 88 different for BGPsec than for origin validation. 90 BGPsec need be spoken only by an AS's eBGP speaking, AKA border, 91 routers, and is designed so that it can be used to protect 92 announcements which are originated by small edge routers. This has 93 special operational considerations. 95 Different prefixes may have different timing and replay protection 96 considerations. 98 2. Suggested Reading 100 It is assumed that the reader understands BGP, [RFC4271], BGPsec, 101 [I-D.ietf-sidr-bgpsec-overview], the RPKI, see [RFC6480], the RPKI 102 Repository Structure, see [RFC6481], and ROAs, see [RFC6482]. 104 3. RPKI Distribution and Maintenance 106 All non-ROA considerations in the section on RPKI Distribution and 107 Maintenance of [RFC7115] apply. 109 4. AS/Router Certificates 111 As described in [I-D.ietf-sidr-rtr-keying] BGPsec-speaking routers 112 are either capable of generating their own public/private key-pairs 113 and having their certificates signed and published in the RPKI by the 114 RPKI CA system, and/or are given public/private key-pairs by the 115 operator. 117 A site/operator MAY use a single certificate/key in all their 118 routers, one certificate/key per router, or any granularity in 119 between. 121 A large operator, concerned that a compromise of one router's key 122 would make other routers vulnerable, may accept a more complex 123 certificate/key distribution burden to reduce this exposure. 125 On the other extreme, an edge site with one or two routers may choose 126 to use a single certificate/key. 128 In anticipation of possible key compromise, a prudent operator will 129 pre-provision each router's 'next' key in the RPKI so there is no 130 propagation delay for provisioning the new key. 132 5. Within a Network 134 BGPsec is spoken by edge routers in a network, those which border 135 other networks/ASs. 137 In a fully BGPsec enabled AS, Route Reflectors MUST have BGPsec 138 enabled if and only if there are eBGP speakers in their client cone, 139 i.e. an RR client or the transitive closure of their customers' 140 customers' customers' .... 142 A BGPsec capable router MAY use the data it receives to influence 143 local policy within its network, see Section 7. In deployment this 144 policy should fit into the AS's existing policy, preferences, etc. 146 This allows a network to incrementally deploy BGPsec enabled border 147 routers. 149 eBGP speakers which face more critical peers or up/downstreams would 150 be candidates for early deployment. Both securing one's own 151 announcements and validating received announcements should be 152 considered in partial deployment. 154 The operator should be aware that BGPsec, as any other policy change, 155 can cause traffic shifts in their network. And, as with normal 156 policy shift practice, a prudent operator has tools and methods to 157 predict, measure, modify, etc. 159 On the other hand, an operator wanting to monitor router loading, 160 shifts in traffic, etc. might deploy incrementally while watching 161 those and similar effects. 163 As they are not formally verifiable, an eBGP listener SHOULD NOT 164 strongly trust unsigned security markings such as communities 165 received across a trust boundary. 167 6. Considerations for Edge Sites 169 An edge site which does not provide transit and trusts its 170 upstream(s) SHOULD only originate a signed prefix announcement and 171 need not validate received announcements. 173 BGPsec protocol capability negotiation provides for a speaker signing 174 the data it sends without being able to accept signed data. Thus a 175 smallish edge router may hold only its own signing key(s), sign it's 176 announcements, but not receive signed announcements and therefore not 177 need to deal with the majority of the RPKI. Thus such routers CPU, 178 RAM, and crypto needs are trivial and additional hardware should not 179 be needed. 181 As the vast majority (84%) of ASs are stubs, and they announce the 182 majority of prefixes, this allows for simpler and less expensive 183 incremental deployment. It may also mean that edge sites concerned 184 with routing security will be attracted to upstreams which support 185 BGPsec. 187 7. Routing Policy 189 Unlike origin validation based on the RPKI, BGPsec marks a received 190 announcement as Valid or Invalid, there is no explicit NotFound 191 state. In some sense, an unsigned BGP4 path is the equivalent of 192 NotFound. How this is used in routing is up to the operator's local 193 policy. See [RFC6811]. 195 As BGPsec will be rolled out over years and does not allow for 196 intermediate non-signing edge routers, coverage will be spotty for a 197 long time. Hence a normal operator's policy SHOULD NOT be overly 198 strict, perhaps preferring Valid paths and giving very low 199 preference, but still using, Invalid paths. 201 Operators should be aware that accepting Invalid announcements, no 202 matter how de-preffed, will often be the equivalent of treating them 203 as fully Valid. Consider having a Valid announcement from neighbor V 204 for prefix 10.0.0.0/16 and an Invalid announcement for 10.0.666.0/24 205 from neighbor I. If local policy on the router is not configured to 206 discard the Invalid announcement from I, then longest match 207 forwarding will send packets to neighbor I no matter the value of 208 local preference. 210 A BGPsec speaker validates signed paths at the eBGP edge. 212 Local policy on the eBGP edge MAY convey the validation state of a 213 BGP signed path through normal local policy mechanisms, e.g. setting 214 a BGP community for internal use, or modifying a metric value such as 215 local-preference or MED. Some may choose to use the large Local-Pref 216 hammer. Others may choose to let AS-Path rule and set their internal 217 metric, which comes after AS-Path in the BGP decision process. 219 Because of possible RPKI version skew, an AS Path which does not 220 validate at router R0 might validate at R1. Therefore, signed paths 221 that are Invalid and yet propagated (because they are chosen as best 222 path) SHOULD have their signatures kept intact and MUST be signed if 223 sent to external BGPsec speakers. 225 This implies that updates which a speaker judges to be Invalid MAY be 226 propagated to iBGP peers. Therefore, unless local policy ensures 227 otherwise, a signed path learned via iBGP MAY be Invalid. If needed, 228 the validation state should be signaled by normal local policy 229 mechanisms such as communities or metrics. 231 On the other hand, local policy on the eBGP edge might preclude iBGP 232 or eBGP announcement of signed AS Paths which are Invalid. 234 A BGPsec speaker receiving a path SHOULD perform origin validation 235 per [RFC6811] and [RFC7115]. 237 A route server is usually 'transparent', most importantly not 238 inserting its own AS into the AS_Path, to not lengthen the AS hop 239 count and thereby reduce the likelihood of best path selection. See 240 2.2.2 of [I-D.ietf-idr-ix-bgp-route-server]. A BGPsec-aware route 241 server needs to validate the incoming BGPSEC_Path, and to forward 242 updates which can be validated by clients which know the route 243 server's AS. The route server uses pCount of zero to not increase 244 the effective AS hop count. 246 If it is known that a BGPsec neighbor is not a transparent route 247 server, and the router provides a knob to disallow a received pCount 248 (prepend count, zero for transparent route servers) of zero, that 249 knob SHOULD be applied. Routers should default to this knob 250 disallowing pCount 0. 252 To prevent exposure of the internals of BGP Confederations [RFC5065], 253 a BGPsec speaker which is a Member-AS of a Confederation MUST NOT 254 sign updates sent to another Member-AS of the same Confederation. 256 8. Notes 258 For protection from attacks replaying BGP data on the order of a day 259 or longer old, re-keying routers with new keys (previously) 260 provisioned in the RPKI is sufficient. For one approach, see 261 [I-D.ietf-sidr-bgpsec-rollover] 263 Like the DNS, the global RPKI presents only a loosely consistent 264 view, depending on timing, updating, fetching, etc. Thus, one cache 265 or router may have different data about a particular prefix or router 266 than another cache or router. There is no 'fix' for this, it is the 267 nature of distributed data with distributed caches. 269 Operators who manage certificates SHOULD have RPKI GhostBuster 270 Records (see [RFC6493]), signed indirectly by End Entity 271 certificates, for those certificates on which others' routing depends 272 for certificate and/or ROA validation. 274 Operators should be aware of impending algorithm transitions, which 275 will be rare and slow-paced, see see [RFC6916]. They should work 276 with their vendors to ensure support for new algorithms. 278 As a router must evaluate certificates and ROAs which are time 279 dependent, routers' clocks MUST be correct to a tolerance of 280 approximately an hour. 282 If a router has reason to believe its clock is seriously incorrect, 283 e.g. it has a time earlier than 2011, it SHOULD NOT attempt to 284 validate incoming updates. It SHOULD defer validation until it 285 believes it is within reasonable time tolerance. 287 Servers should provide time service, such as [RFC5905], to client 288 routers. 290 9. Security Considerations 292 The major security considerations for the BGPsec protocol are 293 described in [I-D.ietf-sidr-bgpsec-protocol]. 295 10. IANA Considerations 297 This document has no IANA Considerations. 299 11. Acknowledgments 301 The author wishes to thank the BGPsec design group, Thomas King, and 302 Arnold Nipper. 304 12. References 306 12.1. Normative References 308 [I-D.ietf-sidr-bgpsec-overview] 309 Lepinski, M. and S. Turner, "An Overview of BGPSEC", 310 draft-ietf-sidr-bgpsec-overview-02 (work in progress), May 311 2012. 313 [I-D.ietf-sidr-bgpsec-protocol] 314 Lepinski, M., "BGPSEC Protocol Specification", draft-ietf- 315 sidr-bgpsec-protocol-07 (work in progress), February 2013. 317 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 318 Requirement Levels", BCP 14, RFC 2119, March 1997. 320 [RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support 321 Secure Internet Routing", RFC 6480, February 2012. 323 [RFC6481] Huston, G., Loomans, R., and G. Michaelson, "A Profile for 324 Resource Certificate Repository Structure", RFC 6481, 325 February 2012. 327 [RFC6482] Lepinski, M., Kent, S., and D. Kong, "A Profile for Route 328 Origin Authorizations (ROAs)", RFC 6482, February 2012. 330 [RFC6493] Bush, R., "The Resource Public Key Infrastructure (RPKI) 331 Ghostbusters Record", RFC 6493, February 2012. 333 [RFC7115] Bush, R., "Origin Validation Operation Based on the 334 Resource Public Key Infrastructure (RPKI)", BCP 185, 335 RFC 7115, DOI 10.17487/RFC7115, January 2014, 336 . 338 12.2. Informative References 340 [I-D.ietf-idr-ix-bgp-route-server] 341 Jasinska, E., Hilliard, N., Raszuk, R., and N. Bakker, 342 "Internet Exchange Route Server", draft-ietf-idr-ix-bgp- 343 route-server-02 (work in progress), February 2013. 345 [I-D.ietf-sidr-bgpsec-rollover] 346 Gagliano, R., Patel, K., and B. Weis, "BGPSEC router key 347 rollover as an alternative to beaconing", draft-ietf-sidr- 348 bgpsec-rollover-01 (work in progress), October 2012. 350 [I-D.ietf-sidr-rtr-keying] 351 Turner, S., Patel, K., and R. Bush, "Router Keying for 352 BGPsec", draft-ietf-sidr-rtr-keying-01 (work in progress), 353 February 2013. 355 [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway 356 Protocol 4 (BGP-4)", RFC 4271, January 2006. 358 [RFC5065] Traina, P., McPherson, D., and J. Scudder, "Autonomous 359 System Confederations for BGP", RFC 5065, August 2007. 361 [RFC5905] Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network 362 Time Protocol Version 4: Protocol and Algorithms 363 Specification", RFC 5905, June 2010. 365 [RFC6811] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R. 366 Austein, "BGP Prefix Origin Validation", RFC 6811, January 367 2013. 369 [RFC6916] Gagliano, R., Kent, S., and S. Turner, "Algorithm Agility 370 Procedure for the Resource Public Key Infrastructure 371 (RPKI)", BCP 182, RFC 6916, DOI 10.17487/RFC6916, April 372 2013, . 374 Author's Address 376 Randy Bush 377 Internet Initiative Japan 378 5147 Crystal Springs 379 Bainbridge Island, Washington 98110 380 US 382 Email: randy@psg.com