Network Working Group X. Xu
Internet-Draft Huawei
Intended status: Standards Track S. Somasundaram
Expires: April 23, 2015 Alcatel-Lucent
C. Jacquenet
France Telecom
R. Raszuk
Mirantis Inc.
October 20, 2014

BIER Encapsulation
draft-xu-bier-encapsulation-01

Abstract

Bit Index Explicit Replication (BIER) is a new multicast forwarding paradigm which doesn't require an explicit tree-building protocol and doesn't require intermediate routers to maintain any multicast state. This document proposes a transport-independent BIER encapsulation header which is applicable in any kind of transport networks.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

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This Internet-Draft will expire on April 23, 2015.

Copyright Notice

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Table of Contents

1. Introduction

Bit Index Explicit Replication (BIER) [I-D.wijnands-bier-architecture] is a new multicast forwarding paradigm which doesn't require an explicit tree-building protocol and doesn't require intermediate routers to maintain any multicast state. As described in [I-D.wijnands-bier-architecture], BIER requires that a multicast data packet (e.g., an IP packet or an MPLS packet) to be encapsulated with a BIER header that carries the information needed for supporting the BIER forwarding procedures. This information at least includes Set-Identifier (SI), Multi-Topology Identifier (MT-ID) and BitString. The SI and the BitString are used together to identify the set of egress BFRs (BFERs) to which the packet must be delivered. In addition, to indicate what type of payload is following the BIER header, a protocol type field is neccessary. This document proposes a transport-independent BIER encapsulation header which is applicable in any kind of transport networks.

1.1. Requirements Language

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].

2. Terminology

This memo makes use of the terms defined in [I-D.wijnands-bier-architecture].

3. BIER Header

The BIER header is shown as follows:

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  Ver  |   BS Length   |       SI      |         MT-ID         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           BFIR-ID             |         Protocol Type         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           Entropy             |      DS       |      TTL      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                BitString  (first 32 bits)                     ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                                                               ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                BitString  (last 32 bits)                      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

4. Transport Encapsulation for BIER Header

Since the BIER encapsulation format as specified in Section 3 is transport-independent, it can be encapsulated with any type of transport encapsulation headers, such as Ethernet header, PPP header, IP header, MPLS header, GRE header, UDP header etc. It requires for each possible transport encapsulation header to be able to indicate the payload is an BIER header. For instance, In the BIER-in-MAC encapsulation case, the EtherType field in the Ethernet header is used. In the BIER-in-IP encapsulation case, the Protocol or Next-Header field in the IPv4 or IPv6 header is used. In the BIER-in-MPLS encapsulation case, either the Protocol Type field [I-D.xu-mpls-payload-protocol-identifier] within the MPLS packet or a to-be-assigned Extended Spcial Purpose label [RFC7274] is used.

5. Acknowledgements

TBD.

6. IANA Considerations

This document includes a request to IANA to allocate an EtherType code,a PPP protocol code, an IPv4 protocol code, an IPv6 Next-Header code, a UDP destination port for carring the BIER-encapsulated packet over the corresponding transport networks. Furthermore, This document includes a request to IANA to allocate EtherType codes for VXLAN and VXLAN-GPE respectively.

7. Security Considerations

TBD.

8. References

8.1. Normative References

[ETYPES] The IEEE Registration Authority, "IEEE 802 Numbers", 2012.
[I-D.wijnands-bier-architecture] Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T. and S. Aldrin, "Multicast using Bit Index Explicit Replication", Internet-Draft draft-wijnands-bier-architecture-01, October 2014.
[I-D.xu-mpls-payload-protocol-identifier] Xu, X. and M. Chen, "MPLS Payload Protocol Identifier", Internet-Draft draft-xu-mpls-payload-protocol-identifier-00, September 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC7274] Kompella, K., Andersson, L. and A. Farrel, "Allocating and Retiring Special-Purpose MPLS Labels", RFC 7274, June 2014.

8.2. Informative References

[I-D.quinn-vxlan-gpe] Quinn, P., Agarwal, P., Fernando, R., Lewis, D., Kreeger, L., Smith, M., Yadav, N., Yong, L., Xu, X., Elzur, U. and P. Garg, "Generic Protocol Extension for VXLAN", Internet-Draft draft-quinn-vxlan-gpe-03, July 2014.
[RFC2474] Nichols, K., Blake, S., Baker, F. and D. Black, "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers", RFC 2474, December 1998.
[RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L. and P. Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", RFC 4915, June 2007.
[RFC5120] Przygienda, T., Shen, N. and N. Sheth, "M-ISIS: Multi Topology (MT) Routing in Intermediate System to Intermediate Systems (IS-ISs)", RFC 5120, February 2008.
[RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger, L., Sridhar, T., Bursell, M. and C. Wright, "Virtual eXtensible Local Area Network (VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks", RFC 7348, August 2014.

Authors' Addresses

Xiaohu Xu Huawei EMail: xuxiaohu@huawei.com
S Somasundaram Alcatel-Lucent EMail: somasundaram.s@alcatel-lucent.com
Christian Jacquenet France Telecom EMail: christian.jacquenet@orange.com
Robert Raszuk Mirantis Inc. EMail: robert@raszuk.net