Документ взят из кэша поисковой машины. Адрес оригинального документа : http://mirror.msu.net/pub/rfc-editor/internet-drafts/draft-tanmir-rtgwg-bfd-mc-lag-ip-00.txt Дата изменения: Mon Mar 21 20:30:28 2016 Дата индексирования: Sun Apr 10 07:38:56 2016 Кодировка:

RTG Working Group G. Mirsky
Internet-Draft J. Tantsura
Updates: 7130 (if approved) Ericsson
Intended status: Standards Track March 21, 2016
Expires: September 22, 2016


Bidirectional Forwarding Detection (BFD) on Multi-chassis Ling
Aggregation Group (MC-LAG) Interfaces in IP Networks
draft-tanmir-rtgwg-bfd-mc-lag-ip-00

Abstract

This document discusses use of Bidirectional Forwarding Detection for
Multi-chassis Link Aggregation Group to provide faster than Link
Aggregation Control Protocol convergence.

Status of This Memo

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 September 22, 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
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.



Mirsky & Tantsura Expires September 22, 2016 [Page 1]

Internet-Draft BFD for MC-LAG over IP March 2016


Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions used in this document . . . . . . . . . . . . 2
1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 2
1.1.2. Requirements Language . . . . . . . . . . . . . . . . 2
2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
3. BFD on MC-LAG with IP only data plane . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 3
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3
7. Normative References . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4

1. Introduction

The [RFC7130] defines use of Bidirectional Forwarding Detection (BFD)
on Link Aggregation Group (LAG) interfaces. Multi-chassis LAG (MC-
LAG) is type of LAG [IEEE.802.1AX.2008] with member links terminated
on separate chassis. [IEEE.802.1AX.2008] does not specify MC-LAG but
doesn't preclude it either. Link Aggregation Control Protocol
(LACP), also defined in [IEEE.802.1AX.2008], can work with MC-LAG
but, as in LAG case, can detect link failure only in range of single
seconds. This document defines how mechanism defined to work on LAG
interfaces [RFC7130] can be adopted to MC-LAG case to enable sub-
second detection of member link failure.

1.1. Conventions used in this document

1.1.1. Terminology

BFD: Bidirectional Forwarding Detection

LAG: Link Aggregation Group

LACP: Link Aggregation Control Protocol

MC-LAG: Multi-chassis Link Aggregation Group

1.1.2. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119].






Mirsky & Tantsura Expires September 22, 2016 [Page 2]

Internet-Draft BFD for MC-LAG over IP March 2016


2. Problem Statement

[RFC7130] does not specify selection of the destination IP address
for the BFD control packet. The only requirement related to the
selection is in Section 2.1 stating that the use of address family
across all member links of the given LAG MUST be consistent across
all the links. Thus it is implied that the same unicast IP address
will be used on all member links of the LAG as use of different
destination addresses would defeat the purpose of [RFC7130]
transforming the case into set of single-hop BFD sessions [RFC5881].
But single unicast IP address may not work in MC-LAG case as the
member links are terminated on the separate chassis. This document
proposes how to overcome this problem if using IP or Multi-Protocol
Label Switching (MPLS) data plane encapsulation.

3. BFD on MC-LAG with IP only data plane

As described in [RFC7130] micro-BFD session on the LAG interfaces may
use either IPv4 or IPv6 address family. In some cases two sessions,
one with IPv4 and one with IPv6 addresses, may run concurrently.
This document doesn't change any of these but specifies selection of
the destination IP address in MC-LAG use case:

o if IPv4 address family being used for micro-BFD session, then the
link-local multicast address 224.0.0.0/24 SHOULD be used as the
destination IP address. Subnet broadcast address MAY be used as
the destination IP address as well;

o if the address family used is IPv6, then the IPv6 link-local
multicast address FF02:0:0:0:0:0:0:2 MUST be used as the
destination IP address.

4. IANA Considerations

This document makes no requests for IANA allocations. This section
may be deleted by RFC Editor.

5. Security Considerations

Security considerations discussed in [RFC7130] apply to this
document.

6. Acknowledgements








Mirsky & Tantsura Expires September 22, 2016 [Page 3]

Internet-Draft BFD for MC-LAG over IP March 2016


7. Normative References

[IEEE.802.1AX.2008]
"IEEE Standard for Local and metropolitan area networks -
Link Aggregation", IEEE 802.1-AX, November 2008.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
.

[RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881,
DOI 10.17487/RFC5881, June 2010,
.

[RFC7130] Bhatia, M., Ed., Chen, M., Ed., Boutros, S., Ed.,
Binderberger, M., Ed., and J. Haas, Ed., "Bidirectional
Forwarding Detection (BFD) on Link Aggregation Group (LAG)
Interfaces", RFC 7130, DOI 10.17487/RFC7130, February
2014, .

Authors' Addresses

Greg Mirsky
Ericsson

Email: gregory.mirsky@ericsson.com


Jeff Tantsura
Ericsson

Email: jeff.tantsura@ericsson.com

















Mirsky & Tantsura Expires September 22, 2016 [Page 4]