Internet DRAFT - draft-wang-bess-evpn-control-word

draft-wang-bess-evpn-control-word







BESS Working Group                                               H. Wang
Internet-Draft                                               D. Eastlake
Intended status: Experimental                        Huawei Technologies
Expires: April 25, 2019                                 October 22, 2018


                     EVPN ELAN use of Control Words
                  draft-wang-bess-evpn-control-word-00

Abstract

   This document describes a method for negotiating and using EVPN
   control words for ELAN service.

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].

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 https://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 April 25, 2019.

Copyright Notice

   Copyright (c) 2018 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
   (https://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



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   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Control word Next-Hop Dependent Capability  . . . . . . . . .   2
   3.  The Control Plane Process . . . . . . . . . . . . . . . . . .   3
   4.  The Data Plane Process  . . . . . . . . . . . . . . . . . . .   3
   5.  Other Considerations  . . . . . . . . . . . . . . . . . . . .   3
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   9.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   The usage of control words for Layer 2 services is described in RFC
   7432 [RFC7432] and in some drafts on traditional VPLS but these
   documents do not explain how to deploy and negotiate control words.
   According to these documents, control words can only be used if all
   devices have control words enabled.  If one of the devices does not
   have the control word enabled, that device cannot communicate with
   the other devices.

   RFC 8214 [RFC8214] defines the EVPN VPWS service and describes the
   negotiation process for the use of control words.  However, the
   negotiation process described is only applicable to a P2P service
   such as VPWS, and is not applicable to an MP2MP service such as VPLS.

   This documents aims to define a control word negotiation and usage
   mechanism in an EVPN ELAN scenario.

2.  Control word Next-Hop Dependent Capability

   The Control Word Next-Hop Capability has type code TBD and a length
   of 0 or 3 octet.

   The inclusion of the "Control word" Next-Hop Capability indicates
   that the BGP Next-Hop can be sent packets, for all routes indicated
   in the NRLI, with a control word added immediately after the label
   stack advertised with the NLRI.

   When the receiver receives a route that carries the capability, it
   can decide whether to add the control word to the packet according to
   its local capability.



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3.  The Control Plane Process

   The egress router needs to use the control word indicator label to
   determine whether there is a control word in the packet.

   There are two methods to specified the control word indicator label:

      The first method is to apply for a reserved label to indicate
      whether the packet contains a control word;

      The second method is to apply for a new label when the sending
      router advertises the control word capability, which is used to
      indicate whether the control word is included in the packet.

   When the value of the control word capability length is 0, it means
   we should use a reserved label as the control word indication label,
   which needs be assigned by IANA.

   If the value of the control word capability length is 3, the sending
   router must apply a new label to act as the control word indication
   label.

   Either of the above two methods can be used, and the first method is
   recommended.

4.  The Data Plane Process

   The ingress router receives the routes with the control word
   capability attribute and, if the ingress router supports the control
   word capability and allows the control word capability to be carried
   when forwarding traffic to the egress router, a control word
   indicator label is added at the label stacks' bottom and then a
   4-byte control word is added.  If the ingress router does not support
   the control word capability or does not recognize the control word
   capability, the ingress router maintains the message consistent with
   the previous behavior when forwarding the packet to the egress
   router.

   When the egress router receives a packet from the MPLS network and
   finds a control word indication label in the packet, it means that
   the packet contains a control word, so the egress router does the
   control word process.

5.  Other Considerations

   For the VXLAN and SRv6 networks, the current hash rule does not have
   the problem of Layer 2 services in the MPLS network.  Therefore, no




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   support is required.  If the attribute is received, it can be
   ignored.

6.  IANA Considerations

   TBD

7.  Security Considerations

   TBD

8.  Acknowledgements

   TBD

9.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC7432]  Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A.,
              Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based
              Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February
              2015, <https://www.rfc-editor.org/info/rfc7432>.

   [RFC8214]  Boutros, S., Sajassi, A., Salam, S., Drake, J., and J.
              Rabadan, "Virtual Private Wire Service Support in Ethernet
              VPN", RFC 8214, DOI 10.17487/RFC8214, August 2017,
              <https://www.rfc-editor.org/info/rfc8214>.

Authors' Addresses

   Haibo (Rainsword) Wang
   Huawei Technologies
   Huawei Bld., No.156 Beiqing Road
   Beijing 100085
   China

   Email: rainsword.wang@huawei.com










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   Donald Eastlake 3rd
   Huawei Technologies
   1424 Pro Shop Court
   Davenport, FL 33896
   USA

   Phone: +1-508-333-2270
   Email: d3e3e3@gmail.com











































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