idnits 2.17.1 draft-ietf-bfd-seamless-ip-02.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (June 19, 2015) is 3234 days in the past. Is this intentional? 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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-11) exists of draft-ietf-bfd-seamless-base-04 Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force N. Akiya 3 Internet-Draft Big Switch Networks 4 Intended status: Standards Track C. Pignataro 5 Expires: December 21, 2015 D. Ward 6 Cisco Systems 7 June 19, 2015 9 Seamless Bidirectional Forwarding Detection (S-BFD) for 10 IPv4, IPv6 and MPLS 11 draft-ietf-bfd-seamless-ip-02 13 Abstract 15 This document defines procedures to use Seamless Bidirectional 16 Forwarding Detection (S-BFD) for IPv4, IPv6 and MPLS environments. 18 Requirements Language 20 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 21 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 22 document are to be interpreted as described in RFC 2119 [RFC2119]. 24 Status of This Memo 26 This Internet-Draft is submitted in full conformance with the 27 provisions of BCP 78 and BCP 79. 29 Internet-Drafts are working documents of the Internet Engineering 30 Task Force (IETF). Note that other groups may also distribute 31 working documents as Internet-Drafts. The list of current Internet- 32 Drafts is at http://datatracker.ietf.org/drafts/current/. 34 Internet-Drafts are draft documents valid for a maximum of six months 35 and may be updated, replaced, or obsoleted by other documents at any 36 time. It is inappropriate to use Internet-Drafts as reference 37 material or to cite them other than as "work in progress." 39 This Internet-Draft will expire on December 21, 2015. 41 Copyright Notice 43 Copyright (c) 2015 IETF Trust and the persons identified as the 44 document authors. All rights reserved. 46 This document is subject to BCP 78 and the IETF Trust's Legal 47 Provisions Relating to IETF Documents 48 (http://trustee.ietf.org/license-info) in effect on the date of 49 publication of this document. Please review these documents 50 carefully, as they describe your rights and restrictions with respect 51 to this document. Code Components extracted from this document must 52 include Simplified BSD License text as described in Section 4.e of 53 the Trust Legal Provisions and are provided without warranty as 54 described in the Simplified BSD License. 56 Table of Contents 58 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 59 2. S-BFD UDP Port . . . . . . . . . . . . . . . . . . . . . . . 2 60 3. S-BFD Echo UDP Port . . . . . . . . . . . . . . . . . . . . . 3 61 4. S-BFD Control Packet Demultiplexing . . . . . . . . . . . . . 3 62 5. Initiator Procedures . . . . . . . . . . . . . . . . . . . . 3 63 5.1. Details of S-BFD Control Packet Sent by SBFDInitiator . . 3 64 5.2. Target vs. Remote Entity (S-BFD Discriminator) . . . . . 4 65 6. Responder Procedures . . . . . . . . . . . . . . . . . . . . 5 66 6.1. Details of S-BFD Control Packet Sent by SBFDReflector . . 5 67 7. Security Considerations . . . . . . . . . . . . . . . . . . . 5 68 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 69 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 70 10. Contributing Authors . . . . . . . . . . . . . . . . . . . . 6 71 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 72 11.1. Normative References . . . . . . . . . . . . . . . . . . 6 73 11.2. Informative References . . . . . . . . . . . . . . . . . 7 74 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 76 1. Introduction 78 Seamless Bidirectional Forwarding Detection (S-BFD), 79 [I-D.ietf-bfd-seamless-base], defines a generalized mechanism to 80 allow network nodes to seamlessly perform continuity checks to remote 81 entities. This document defines necessary procedures to use S-BFD on 82 IPv4, IPv6 and MPLS environments. 84 The reader is expected to be familiar with the IP, MPLS BFD and S-BFD 85 terminologies and protocol constructs. 87 2. S-BFD UDP Port 89 A new UDP port is defined for the use of the S-BFD on IPv4, IPv6 and 90 MPLS environments: 7784. SBFDReflector session MUST listen for 91 incoming S-BFD control packets on the port 7784. SBFDInitiator 92 sessions MUST transmit S-BFD control packets with destination port 93 7784. The source port of the S-BFD control packets transmitted by 94 SBFDInitiator sessions can be of any but MUST NOT be 7784. The same 95 UDP source port number MUST be used for all S-BFD control packets 96 associated with a particular SBFDInitiator session. The source port 97 number MAY be unique among all SBFDInitiator sessions on the system. 99 3. S-BFD Echo UDP Port 101 The BFD Echo port defined by [RFC5881], port 3785, is used for the 102 S-BFD Echo function on IPv4, IPv6 and MPLS environments. 103 SBFDInitiator sessions MUST transmit S-BFD echo packets with 104 destination port 3785. This document defines only the UDP port value 105 for the S-BFD Echo function. The source port and the procedures for 106 the S-BFD Echo function are outside the scope of this document. 108 4. S-BFD Control Packet Demultiplexing 110 Received BFD control packet MUST be demultiplexed with the 111 destination UDP port field. If the port is 7784, then the packet 112 MUST be looked up to locate a corresponding SBFDReflector session 113 based on the value from the "your discriminator" field in the table 114 describing S-BFD discriminators. If the port is not 7784, then the 115 packet MUST be looked up to locate a corresponding SBFDInitiator 116 session or classical BFD session based on the value from the "your 117 discriminator" field in the table describing BFD discriminators. If 118 the located session is an SBFDInitiator, then the destination IP 119 address of the packet SHOULD be validated to be for self. 121 5. Initiator Procedures 123 S-BFD control packets are transmitted with IP header, UDP header and 124 BFD control header ([RFC5880]). When S-BFD control packets are 125 explicitly label switched (i.e. not IP routed which happen to go over 126 an LSP, but explicitly sent on a specific LSP), the former is 127 prepended with a label stack. Note that this document does not make 128 a distinction between a single-hop S-BFD scenario and a multi-hop 129 S-BFD scenario, both scenarios are supported. 131 Necessary values in the BFD control headers are described in 132 [I-D.ietf-bfd-seamless-base]. Section 5.1 describes necessary values 133 in the MPLS header, IP header and UDP header when an SBFDInitiator on 134 the initiator is sending S-BFD control packets. 136 5.1. Details of S-BFD Control Packet Sent by SBFDInitiator 138 o Specifications common to both IP routed S-BFD control packets and 139 explicitly label switched S-BFD control packets: 141 * Source IP address field of the IP header MUST be set to a local 142 IP address that is expected to be routable by the target (i.e. 144 not IPv6 link-local address when the target is multiple hops 145 away). 147 * UDP destination port MUST be set to a well-known UDP 148 destination port assigned for S-BFD: 7784. 150 * UDP source port MUST be set to a value that is not 7784. 152 o Specifications for IP routed S-BFD control packets: 154 * Destination IP address field of the IP header MUST set to an IP 155 address of the target. 157 * TTL field of the IP header SHOULD be set to 255. 159 o Specifications for explicitly label switched S-BFD control 160 packets: 162 * S-BFD control packets MUST have the label stack that is 163 expected to reach the target. 165 * TTL field of the top most label SHOULD be 255. 167 * The destination IP address MUST be chosen from the 127/8 range 168 for IPv4 and from the 0:0:0:0:0:FFFF:7F00/104 range for IPv6. 170 * TTL field of the IP header MUST be set to 1. 172 5.2. Target vs. Remote Entity (S-BFD Discriminator) 174 Typically, an S-BFD control packet will have "your discriminator" 175 field corresponding to an S-BFD discriminator of the remote entity 176 located on the target network node defined by the destination IP 177 address or the label stack. It is, however, possible for an 178 SBFDInitiator to carefully set "your discriminator" and TTL fields to 179 perform a continuity test towards a target but to a transit network 180 node. 182 Section 5.1 intentionally uses the word "target", instead of "remote 183 entity", to accommodate this possible S-BFD usage through TTL expiry. 184 This also requires S-BFD control packets not be dropped by the 185 responder node due to TTL expiry. Thus implementations on the 186 responder MUST allow received S-BFD control packets taking TTL expiry 187 exception path to reach corresponding reflector BFD session. 189 6. Responder Procedures 191 S-BFD control packets are IP routed back to the initiator, and will 192 have IP header, UDP header and BFD control header. If an 193 SBFDReflector receives an S-BFD control packet with UDP source port 194 as 7784, the packet MUST be discarded. Necessary values in the BFD 195 control header are described in [I-D.ietf-bfd-seamless-base]. 196 Section 6.1 describes necessary values in the IP header and UDP 197 header when an SBFDReflector on the responder is sending S-BFD 198 control packets. 200 6.1. Details of S-BFD Control Packet Sent by SBFDReflector 202 o Destination IP address field of the IP header MUST be copied from 203 source IP address field of received S-BFD control packet. 205 o Source IP address field of the IP header MUST be set to a local IP 206 address that is expected to be visible by the initiator (i.e. not 207 IPv6 link-local address when the initiator is multiple hops away). 209 o TTL field of the IP header SHOULD be set to 255. 211 o UDP destination port MUST be copied from received UDP source port. 213 o UDP source port MUST be copied from received UDP destination port. 215 7. Security Considerations 217 Security considerations for S-BFD are discussed in 218 [I-D.ietf-bfd-seamless-base]. Additionally, implementing the 219 following measures will strengthen security aspects of the mechanism 220 described by this document: 222 o Implementations MUST provide filtering capability based on source 223 IP addresses of received S-BFD control packets: [RFC2827]. 225 o Implementations MUST NOT act on received S-BFD control packets 226 containing Martian addresses as source IP addresses. 228 o Implementations MUST ensure that response S-BFD control packets 229 generated to the initiator by the SBFDReflector have a reachable 230 target (ex: destination IP address). 232 8. IANA Considerations 234 A new value 7784 was allocated from the "Service Name and Transport 235 Protocol Port Number Registry". The allocated registry entry is: 237 Service Name (REQUIRED) 238 s-bfd 239 Transport Protocol(s) (REQUIRED) 240 udp 241 Assignee (REQUIRED) 242 IESG 243 Contact (REQUIRED) 244 BFD Chairs 245 Description (REQUIRED) 246 Seamless Bidirectional Forwarding Detection (S-BFD) 247 Reference (REQUIRED) 248 draft-akiya-bfd-seamless-ip 249 Port Number (OPTIONAL) 250 7784 252 9. Acknowledgements 254 The authors would like to thank the BFD WG members for helping to 255 shape the contents of this document. In particular, significant 256 contributions were made by following people: Marc Binderberger, 257 Jeffrey Haas, Santosh Pallagatti, Greg Mirsky, Sam Aldrin, Vengada 258 Prasad Govindan, Mallik Mudigonda and Srihari Raghavan. 260 10. Contributing Authors 262 Tarek Saad 263 Cisco Systems 264 Email: tsaad@cisco.com 266 Siva Sivabalan 267 Cisco Systems 268 Email: msiva@cisco.com 270 Nagendra Kumar 271 Cisco Systems 272 Email: naikumar@cisco.com 274 11. References 276 11.1. Normative References 278 [I-D.ietf-bfd-seamless-base] 279 Akiya, N., Pignataro, C., Ward, D., Bhatia, M., and J. 280 Networks, "Seamless Bidirectional Forwarding Detection 281 (S-BFD)", draft-ietf-bfd-seamless-base-04 (work in 282 progress), January 2015. 284 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 285 Requirement Levels", BCP 14, RFC 2119, March 1997. 287 [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection 288 (BFD)", RFC 5880, June 2010. 290 [RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection 291 (BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881, June 292 2010. 294 11.2. Informative References 296 [RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering: 297 Defeating Denial of Service Attacks which employ IP Source 298 Address Spoofing", BCP 38, RFC 2827, May 2000. 300 Authors' Addresses 302 Nobo Akiya 303 Big Switch Networks 305 Email: nobo.akiya.dev@gmail.com 307 Carlos Pignataro 308 Cisco Systems 310 Email: cpignata@cisco.com 312 Dave Ward 313 Cisco Systems 315 Email: wardd@cisco.com