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/MPLS Networks draft-tanmir-rtgwg-bfd-mc-lag-mpls-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/MPLS 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 . . . . . . . . . . . . . . . . 3 2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3 3. BFD on MC-LAG with IP/MPLS data plane . . . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 7. Normative References . . . . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 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 ACH: Associated Channel Header BFD: Bidirectional Forwarding Detection BoS: Bottom of the Stack G-ACh: Generic Associated Channel GAL: Generic Associated Label LAG: Link Aggregation Group LACP: Link Aggregation Control Protocol MC-LAG: Multi-chassis Link Aggregation Group MPLS: Multi-Protocol Label Switching Mirsky & Tantsura Expires September 22, 2016 [Page 2]
Internet-Draft BFD for MC-LAG over IP/MPLS March 2016 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]. 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/MPLS data plane There are more optional encapsulation formats for the case of micro- BFD on MC-LAG over IP/MPLS data plane: o [RFC5586] defined special purpose Generic Associated channel Label (GAL) that MAY be used in MPLS encapsulation of the micro-BFD control packet over MPSL data plane. Depending on the channel type specified in the Associated Channel Header (ACH) that immediately follows after the GAL, micro-BFD MAY use IP/UDP, as displayed in Figure 1 or BFD format, i.e. BFD control packet without IP and UDP headers. Mirsky & Tantsura Expires September 22, 2016 [Page 3]
Internet-Draft BFD for MC-LAG over IP/MPLS March 2016 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GAL | TC |1| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 1|0 0 0 0| Reserved | IPv4 channel (0x0021) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination IP address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source IP address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | UDP header | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ BFD Control Packet ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: BFD on MC-LAG member link on IPv4/MPLS data plane If IP/UDP format of BFD over MC-LAG interfaces is used, then for IPv4 address family the destination IP address MUST be selected from 127/8 range [RFC4379], and if IPv6 address family is used, then the destination IP address MUST be selected from 0:0:0:0:0:FFFF:127/104 range. 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 7. Normative References [IEEE.802.1AX.2008] "IEEE Standard for Local and metropolitan area networks - Link Aggregation", IEEE 802.1-AX, November 2008. Mirsky & Tantsura Expires September 22, 2016 [Page 4]
Internet-Draft BFD for MC-LAG over IP/MPLS March 2016 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <http://www.rfc-editor.org/info/rfc2119>. [RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures", RFC 4379, DOI 10.17487/RFC4379, February 2006, <http://www.rfc-editor.org/info/rfc4379>. [RFC5586] Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed., "MPLS Generic Associated Channel", RFC 5586, DOI 10.17487/RFC5586, June 2009, <http://www.rfc-editor.org/info/rfc5586>. [RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881, DOI 10.17487/RFC5881, June 2010, <http://www.rfc-editor.org/info/rfc5881>. [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, <http://www.rfc-editor.org/info/rfc7130>. 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 5]