--- 1/draft-ietf-bfd-seamless-ip-04.txt 2016-05-04 13:16:06.843273998 -0700 +++ 2/draft-ietf-bfd-seamless-ip-05.txt 2016-05-04 13:16:06.863274501 -0700 @@ -1,21 +1,21 @@ Internet Engineering Task Force N. Akiya Internet-Draft Big Switch Networks Intended status: Standards Track C. Pignataro -Expires: October 15, 2016 D. Ward - Cisco Systems - April 13, 2016 +Expires: November 5, 2016 D. Ward + Cisco + May 4, 2016 Seamless Bidirectional Forwarding Detection (S-BFD) for IPv4, IPv6 and MPLS - draft-ietf-bfd-seamless-ip-04 + draft-ietf-bfd-seamless-ip-05 Abstract This document defines procedures to use Seamless Bidirectional Forwarding Detection (S-BFD) for IPv4, IPv6 and MPLS environments. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this @@ -29,21 +29,21 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on October 15, 2016. + This Internet-Draft will expire on November 5, 2016. Copyright Notice Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -60,78 +60,85 @@ 3. S-BFD Echo UDP Port . . . . . . . . . . . . . . . . . . . . . 3 4. S-BFD Control Packet Demultiplexing . . . . . . . . . . . . . 3 5. Initiator Procedures . . . . . . . . . . . . . . . . . . . . 3 5.1. Details of S-BFD Control Packet Sent by SBFDInitiator . . 4 5.1.1. Target vs. Remote Entity (S-BFD Discriminator) . . . 4 6. Responder Procedures . . . . . . . . . . . . . . . . . . . . 5 6.1. Details of S-BFD Control Packet Sent by SBFDReflector . . 5 7. Security Considerations . . . . . . . . . . . . . . . . . . . 5 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 - 10. Contributing Authors . . . . . . . . . . . . . . . . . . . . 6 + 10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 6 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 11.1. Normative References . . . . . . . . . . . . . . . . . . 7 11.2. Informative References . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction Seamless Bidirectional Forwarding Detection (S-BFD), [I-D.ietf-bfd-seamless-base], defines a generalized mechanism to allow network nodes to seamlessly perform continuity checks to remote entities. This document defines necessary procedures to use S-BFD on IPv4, IPv6 and MPLS environments. The reader is expected to be familiar with the IP [RFC0791] [RFC2460], BFD [RFC5880], MPLS BFD [RFC5884], and S-BFD [I-D.ietf-bfd-seamless-base] terminologies and protocol constructs. 2. S-BFD UDP Port A new UDP port is defined for the use of the S-BFD on IPv4, IPv6 and - MPLS environments: 7784. SBFDReflector session MUST listen for - incoming S-BFD control packets on the port 7784. SBFDInitiator - sessions MUST transmit S-BFD control packets with destination port - 7784. The source port of the S-BFD control packets transmitted by - SBFDInitiator sessions can be any but MUST NOT be 7784. The same UDP - source port number MUST be used for all S-BFD control packets - associated with a particular SBFDInitiator session. The source port - number is unique among all SBFDInitiator sessions on the system. + MPLS environments: 7784. + + On S-BFD control packets from the SBFDInitiator to the SBFDReflector, + the SBFDReflector session MUST listen for incoming S-BFD control + packets on the port 7784. SBFDInitiator sessions MUST transmit S-BFD + control packets with destination port 7784. The source port of the + S-BFD control packets transmitted by SBFDInitiator sessions can be + any but MUST NOT be 7784. The same UDP source port number MUST be + used for all S-BFD control packets associated with a particular + SBFDInitiator session. The source port number is unique among all + SBFDInitiator sessions on the system. + + On S-BFD control packets from the SBFDReflecto to the SBFDInitiator, + the SBFDInitiator MUST listen for reflected S-BFD control packets at + its source port. 3. S-BFD Echo UDP Port The BFD Echo port defined by [RFC5881], port 3785, is used for the S-BFD Echo function on IPv4, IPv6 and MPLS environments. SBFDInitiator sessions MUST transmit S-BFD echo packets with - destination port 3785. This document defines only the UDP port value - for the S-BFD Echo function. The source port and the procedures for - the S-BFD Echo function are outside the scope of this document. + destination port 3785. The setting of the UDP source port [RFC5881] + and the procedures [I-D.ietf-bfd-seamless-base] for the S-BFD Echo + function are outside the scope of this document. 4. S-BFD Control Packet Demultiplexing The S-BFD Control Packet demultiplexing follows the procedure specified in Section 7.1. of [I-D.ietf-bfd-seamless-base]. Received S-BFD control packet MUST be demultiplexed with the destination UDP port field. This procedure for an S-BFD packet is executed on both the initiator and the reflector. If the port is 7784 (i.e., S-BFD packet for - S-BFDReflector)), then the packet MUST be looked up to locate a + S-BFDReflector), then the packet MUST be looked up to locate a corresponding SBFDReflector session based on the value from the "your discriminator" field in the table describing S-BFD discriminators. - If the port is not 7784, then the packet MUST be looked up to locate - a corresponding SBFDInitiator session or classical BFD session based - on the value from the "your discriminator" field in the table - describing BFD discriminators. If the located session is an - SBFDInitiator, then the destination IP address of the packet SHOULD - be validated to be for self. If the packet is a classical BFD - session, then the procedures from [RFC5880] apply. + If the port is not 7784, but the packet is demultiplexed to be for an + SBFDInitiator, then the packet MUST be looked up to locate a + corresponding SBFDInitiator session based on the value from the "your + discriminator" field in the table describing BFD discriminators. In + that case, then the destination IP address of the packet SHOULD be + validated to be for itself. If the packet demultiplexes to a + classical BFD session, then the procedures from [RFC5880] apply. 5. Initiator Procedures S-BFD control packets are transmitted with IP header, UDP header and BFD control header ([RFC5880]). When S-BFD control packets are explicitly label switched (i.e. not IP routed which happen to go over an LSP, but explicitly sent on a specific LSP), the former is prepended with a label stack. Note that this document does not make a distinction between a single-hop S-BFD scenario and a multi-hop S-BFD scenario, both scenarios are supported. @@ -176,27 +183,27 @@ as with [RFC5884]. * TTL field of the IP header MUST be set to 1. 5.1.1. Target vs. Remote Entity (S-BFD Discriminator) Typically, an S-BFD control packet will have "your discriminator" field corresponding to an S-BFD discriminator of the remote entity located on the target network node defined by the destination IP address or the label stack. It is, however, possible for an - SBFDInitiator to carefully set "your discriminator" and TTL fields to - perform a continuity test towards a target, but to a transit network - node and not to the target itself. + SBFDInitiator to carefully set the "your discriminator" and TTL + fields to perform a continuity test in the direction towards a + target, but destined to a transit network node and not to the target + itself. Section 5.1 intentionally uses the word "target", instead of "remote entity", to accommodate this possible S-BFD usage through TTL expiry. - This also requires S-BFD control packets not be dropped by the responder node due to TTL expiry. Thus implementations on the responder MUST allow received S-BFD control packets taking TTL expiry exception path to reach corresponding reflector BFD session. 6. Responder Procedures S-BFD control packets are IP routed back to the initiator, and will have IP header, UDP header and BFD control header. If an SBFDReflector receives an S-BFD control packet with UDP source port @@ -249,59 +256,53 @@ A new value 7784 was allocated from the "Service Name and Transport Protocol Port Number Registry". The allocated registry entry is: Service Name (REQUIRED) s-bfd Transport Protocol(s) (REQUIRED) udp Assignee (REQUIRED) IESG Contact (REQUIRED) - BFD Chairs + BFD Chairs Description (REQUIRED) Seamless Bidirectional Forwarding Detection (S-BFD) Reference (REQUIRED) RFC.this (RFC Editor, please update at publication) Port Number (OPTIONAL) 7784 9. Acknowledgements The authors would like to thank the BFD WG members for helping to shape the contents of this document. In particular, significant contributions were made by following people: Marc Binderberger, Jeffrey Haas, Santosh Pallagatti, Greg Mirsky, Sam Aldrin, Vengada Prasad Govindan, Mallik Mudigonda and Srihari Raghavan. -10. Contributing Authors - - Tarek Saad - Cisco Systems - Email: tsaad@cisco.com +10. Contributors - Siva Sivabalan - Cisco Systems - Email: msiva@cisco.com + The following are key contributors to this document: - Nagendra Kumar - Cisco Systems - Email: naikumar@cisco.com + Tarek Saad, Cisco Systems, Inc. + Siva Sivabalan, Cisco Systems, Inc. + Nagendra Kumar, Cisco Systems, Inc. 11. References 11.1. Normative References [I-D.ietf-bfd-seamless-base] Akiya, N., Pignataro, C., Ward, D., Bhatia, M., and J. Networks, "Seamless Bidirectional Forwarding Detection - (S-BFD)", draft-ietf-bfd-seamless-base-08 (work in - progress), February 2016. + (S-BFD)", draft-ietf-bfd-seamless-base-09 (work in + progress), April 2016. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, . @@ -331,18 +332,18 @@ June 2010, . Authors' Addresses Nobo Akiya Big Switch Networks Email: nobo.akiya.dev@gmail.com Carlos Pignataro - Cisco Systems + Cisco Systems, Inc. Email: cpignata@cisco.com Dave Ward - Cisco Systems + Cisco Systems, Inc. Email: wardd@cisco.com