BGP for Mirror Binding
draft-chen-idr-mbinding-00
The information below is for an old version of the document.
| Document | Type |
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|---|---|---|---|
| Authors | Huaimo Chen , Bruno Decraene , Gyan Mishra , Yanhe Fan , Aijun Wang , Xufeng Liu | ||
| Last updated | 2023-04-12 (Latest revision 2022-10-23) | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
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| Additional resources | Mailing list discussion | ||
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draft-chen-idr-mbinding-00
Network Working Group H. Chen
Internet-Draft Futurewei
Intended status: Standards Track B. Decraene
Expires: 26 April 2023 Orange
G. Mishra
Verizon
Y. Fan
Casa Systems
A. Wang
China Telecom
X. Liu
IBM Corporation
23 October 2022
BGP for Mirror Binding
draft-chen-idr-mbinding-00
Abstract
BGP is used to distribute a binding SID with a list of SIDs to a
node. This document describes extensions to BGP for distributing the
binding SID with the list of SIDs and an identifier of the node.
When detecting the failure of the node, an neighbor of the node
protects the binding SID of the failed node.
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 26 April 2023.
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Copyright Notice
Copyright (c) 2022 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 include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Extensions to BGP . . . . . . . . . . . . . . . . . . . . . . 3
3. Procedure for Updating Information . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5.1. Existing Registry: BGP Tunnel Encapsulation Attribute
sub-TLVs . . . . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1. Normative References . . . . . . . . . . . . . . . . . . 6
6.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
[I-D.ietf-idr-segment-routing-te-policy] specifies how BGP may be
used to distribute a Segment Routing (SR) Policy to a network node.
An SR Policy is an ordered list of segments (i.e., instructions) that
represent a source-routed policy. An SR Policy consists of one or
more candidate paths, each consisting of one or more segment lists.
An SR Policy may contain a binding SID associated with a path
represented by a segment list (i.e., a list of SIDs).
After a BGP as a controller distributes an SR policy containing a
binding SID associated with a list of SIDs to a network node, each
neighbor of the node needs the information about the binding SID for
protecting the binding SID of the node when the node fails. The
information includes the binding SID, the list of SIDs and the
identifier (ID) of the node. This document proposes some procedures
and extensions to BGP for distributing the information.
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2. Extensions to BGP
This section defines a new Binding Protection sub-TLV under a Tunnel
Encapsulation Attribute TLV of type 15 (i.e., SR Policy TLV). A
Tunnel Encapsulation Attribute contains a Tunnel Encapsulation
Attribute TLV.
The structure containing a Binding Protection sub-TLV is shown below.
Attributes:
Tunnel Encapsulation Attribute (23)
Tunnel Type (15): SR Policy TLV
Preference sub-TLV
Binding SID sub-TLV
SRv6 Binding SID sub-TLV
Explicit NULL Label Policy (ENLP) sub-TLV
Priority sub-TLV
Policy Candidate Path Name sub-TLV
Policy Name sub-TLV
Binding Protection sub-TLV
Segment List sub-TLV
Weight sub-TLV
Segment sub-TLV
Segment sub-TLV
...
...
A Binding Protection sub-TLV contains the information about a binding
SID of a network node for a neighbor of the node to protect the
Binding SID of the node when the neighbor detects the failure of the
node.
The format of a Binding Protection sub-TLV is illustrated below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (TBD1) | Length | Flags | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLVs |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Binding Protection sub-TLV Format
Type: Its value (TBD1) is to be assigned by IANA.
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Length: It is variable.
Flags: 1 octet of flags. No flags is defined now. MUST be set to
zero by the sender and MUST be ignored by the receiver.
sub-TLVs: This field contains the sub-TLV below to indicate the node
to be protected (i.e., the protected node).
o Protected Node BGP ID sub-TLV indicating the BGP ID of the
Protected Node.
When a SR Policy (i.e., SR Policy TLV) contains a binding SID and a
path with a protected node, the SR policy is for distributing the
binding information of the node for protecting the binding SID of the
node when the node fails (binding protection for short). The binding
SID is encoded by a Binding SID sub-TLV or SRv6 Binding SID sub-TLV,
the path is encoded by a Segment List Sub-TLV, and the node is
encoded by a Binding Protection sub-TLV.
When a SR Policy contains a binding SID and a path without a
protected node, the SR policy is for replacing the Binding SID with
the path (i.e., the list of SIDs) when the node receives a packet
with the Binding SID (binding for short).
The format of Protected Node BGP ID sub-TLV is illustrated below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (1) | Length (4) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protected Node BGP ID (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Protected Node BGP ID sub-TLV Format
Type: Its value (1) indicates the type of Protected Node BGP ID sub-
TLV.
Length: Its value (4) indicates the length of the value field of the
sub-TLV is 4.
Protected Node BGP ID: 4-octet field contains the BGP identifier
(ID) of the Protected Node.
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3. Procedure for Updating Information
When a BGP sends a piece of binding information to node N in a first
Update message, the BGP sends the corresponding binding protection
information to each neighbor of node N in a second Update message.
The first message contains a first SR Policy carried in
MP_REACH_NLRI. The first SR Policy includes a binding SID and a path
but does not include node N as a protected node. The second message
contains a second SR Policy carried in MP_REACH_NLRI. The second SR
Policy includes the binding SID, the path and node N as a protected
node.
After a BGP sends the binding information to node N, if BGP removes
the binding information from node N through sending a third Update
message to node N, BGP removes the corresponding binding protection
information from each neighbor of node N through sending a fourth
Update message to the neighbor. The third message contains a third
SR Policy carried in MP_UNREACH_NLRI. The third SR Policy includes
the binding SID and the path but does not include node N as a
protected node. The fourth message contains a fourth SR Policy
carried in MP_UNREACH_NLRI. The fourth SR Policy includes the
binding SID, the path and node N as a protected node.
After a BGP sends the binding information to node N, if the BGP
changes the binding information in node N through sending a fifth
Update message to node N, BGP changes the corresponding binding
protection information in each neighbor of node N through sending a
sixth Update message to the neighbor. The fifth message contains a
fifth SR Policy carried in MP_REACH_NLRI. The fifth SR Policy
includes the binding SID and a (changed) path but does not include
node N as a protected node. The sixth message contains a sixth SR
Policy carried in MP_REACH_NLRI. The sixth SR Policy includes the
binding SID, the (changed) path and node N as a protected node.
4. Security Considerations
Protocol extensions defined in this document do not affect the BGP
security other than those as discussed in the Security Considerations
section of [RFC5575].
5. IANA Considerations
5.1. Existing Registry: BGP Tunnel Encapsulation Attribute sub-TLVs
This document requests assigning a new sub-TLV in the registry "BGP
Tunnel Encapsulation Attribute sub-TLVs" as follows:
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+------------+--------------------+-------------+
| Code Point | Description | Reference |
+------------+--------------------+-------------+
| TBD1 | Binding Protection |This document|
+------------+--------------------+-------------+
6. References
6.1. 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>.
[RFC9012] Patel, K., Van de Velde, G., Sangli, S., and J. Scudder,
"The BGP Tunnel Encapsulation Attribute", RFC 9012,
DOI 10.17487/RFC9012, April 2021,
<https://www.rfc-editor.org/info/rfc9012>.
6.2. Informative References
[I-D.ietf-idr-segment-routing-te-policy]
Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P.,
Jain, D., and S. Lin, "Advertising Segment Routing
Policies in BGP", Work in Progress, Internet-Draft, draft-
ietf-idr-segment-routing-te-policy-20, 27 July 2022,
<https://www.ietf.org/archive/id/draft-ietf-idr-segment-
routing-te-policy-20.txt>.
[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
<https://www.rfc-editor.org/info/rfc5575>.
Authors' Addresses
Huaimo Chen
Futurewei
Boston, MA,
United States of America
Email: huaimo.chen@futurewei.com
Bruno Decraene
Orange
France
Email: bruno.decraene@orange.com
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Gyan S. Mishra
Verizon
13101 Columbia Pike
Silver Spring, MD 20904
United States of America
Phone: 301 502-1347
Email: gyan.s.mishra@verizon.com
Yanhe Fan
Casa Systems
United States of America
Email: yfan@casa-systems.com
Aijun Wang
China Telecom
Beiqijia Town, Changping District
Beijing
102209
China
Email: wangaj3@chinatelecom.cn
Xufeng Liu
IBM Corporation
United States of America
Email: xufeng.liu.ietf@gmail.com
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