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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