Pseudowire Redundancy on the Switching Provider Edge (S-PE)
RFC 7795
Internet Engineering Task Force (IETF) J. Dong
Request for Comments: 7795 H. Wang
Category: Standards Track Huawei Technologies
ISSN: 2070-1721 February 2016
Pseudowire Redundancy on the Switching Provider Edge (S-PE)
Abstract
This document describes Multi-Segment Pseudowire (MS-PW) protection
scenarios in which pseudowire redundancy is provided on the Switching
Provider Edge (S-PE) as defined in RFC 5659. Operations of the S-PEs
that provide PW redundancy are specified in this document. Signaling
of the Preferential Forwarding status as defined in RFCs 6870 and
6478 is reused. This document does not require any change to the
Terminating Provider Edges (T-PEs) of MS-PW.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7795.
Copyright Notice
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Dong & Wang Standards Track [Page 1]
RFC 7795 PW Redundancy on S-PE February 2016
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Typical Scenarios of PW Redundancy on S-PE . . . . . . . . . 3
2.1. MS-PW Redundancy on S-PE . . . . . . . . . . . . . . . . 3
2.2. MS-PW Redundancy on S-PE with S-PE Protection . . . . . . 4
3. S-PE Operations . . . . . . . . . . . . . . . . . . . . . . . 4
4. Applications of PW Redundancy on S-PE . . . . . . . . . . . . 5
4.1. Applications in Scenario 1 . . . . . . . . . . . . . . . 5
4.2. Applications in Scenario 2 . . . . . . . . . . . . . . . 6
5. VCCV Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 8
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
[RFC6718] describes the framework and requirements for pseudowire
(PW) redundancy, and [RFC6870] specifies a PW redundancy mechanism
for scenarios where a set of redundant PWs are configured between
Provider Edge (PE) nodes in Single-Segment Pseudowire (SS-PW)
[RFC3985] applications, or between Terminating Provider Edge (T-PE)
nodes in Multi-Segment Pseudowire (MS-PW) [RFC5659] applications.
In some MS-PW scenarios, there are benefits of providing PW
redundancy on Switching Provider Edges (S-PEs), such as reducing the
burden on the access T-PE nodes and enabling faster protection
switching compared to the end-to-end MS-PW protection mechanisms.
This document describes some scenarios in which PW redundancy is
provided on S-PEs and specifies the operations of the S-PEs. The
S-PEs connect to the neighboring T-PEs or S-PEs with PW segments.
For the S-PE that provides PW redundancy for an MS-PW, there is a
single PW segment on one side, which is called the single-homed side,
and there are multiple PW segments on the other side, which is called
the multi-homed side. The scenario in which the S-PE has two multi-
homed sides is out of scope. Signaling of the Preferential
Forwarding status as defined in [RFC6870] and [RFC6478] is reused.
This document does not require any change to the T-PEs of MS-PW.
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].
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