| Internet Engineering Task Force | N. Akiya |
| Internet-Draft | C. Pignataro |
| Intended status: Standards Track | D. Ward |
| Expires: December 28, 2014 | Cisco Systems |
| June 26, 2014 |
Seamless Bidirectional Forwarding Detection (S-BFD) for IPv4, IPv6 and MPLS
draft-akiya-bfd-seamless-ip-03
This document defines procedures to use Seamless Bidirectional Forwarding Detection (S-BFD) for IPv4, IPv6 and MPLS environments.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
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 December 28, 2014.
Copyright (c) 2014 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 carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
Seamless Bidirectional Forwarding Detection (S-BFD), [I-D.ietf-bfd-seamless-base], defines a generalized mechanism to allow network nodes to seamlessly perform connectivity 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, MPLS BFD and S-BFD terminologies and protocol constructs.
S-BFD packets are transmitted with IP header, UDP header and BFD control header ([RFC5880]). When S-BFD packets are explicitly label switched, 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.
Necessary values in the UDP and BFD control headers are described in [I-D.ietf-bfd-seamless-base]. Section 2.1 describes necessary values in the IP and MPLS headers when an SBFDInitiator on the initiator is sending S-BFD packets.
Ed-Note: Discuss whether we want a new associated channel type for S-BFD.
Typically, an S-BFD 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 connectivity test towards a target but to a transit network node.
Section 2.1 intentionally uses the word "target", instead of "remote entity", to accommodate this possible S-BFD usage through TTL expiry. This also requires S-BFD packets not be dropped by the responder node due to TTL expiry. Thus implementations on the responder MUST allow received S-BFD packets taking TTL expiry exception path to reach corresponding reflector BFD session.
S-BFD packets are IP routed back to the initiator, and will have IP header, UDP header and BFD control header. Necessary values in the UDP and BFD control headers are described in [I-D.ietf-bfd-seamless-base]. Section 3.1 describes necessary values in the IP header when an SBFDReflector on the responder is sending S-BFD packets.
Security considerations for S-BFD are discussed in [I-D.ietf-bfd-seamless-base].
No action is required by IANA for this document.
Authors would like to thank Marc Binderberger from Cisco Systems for providing valuable comments.
Tarek Saad
Cisco Systems
Email: tsaad@cisco.com
Siva Sivabalan
Cisco Systems
Email: msiva@cisco.com
Nagendra Kumar
Cisco Systems
Email: naikumar@cisco.com
| [I-D.ietf-bfd-seamless-base] | Akiya, N., Pignataro, C., Ward, D., Bhatia, M. and J. Networks, "Seamless Bidirectional Forwarding Detection (S-BFD)", Internet-Draft draft-ietf-bfd-seamless-base-00, June 2014. |
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. |
| [RFC5880] | Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD)", RFC 5880, June 2010. |