PCE for Mirror Binding
draft-chen-pce-mbinding-00
The information below is for an old version of the document.
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|---|---|---|---|
| Authors | Huaimo Chen , Bruno Decraene , Gyan Mishra , Aijun Wang , Xufeng Liu , Lei Liu | ||
| Last updated | 2022-10-23 | ||
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draft-chen-pce-mbinding-00
Network Working Group H. Chen
Internet-Draft Futurewei
Intended status: Standards Track B. Decraene
Expires: 26 April 2023 Orange
G. Mishra
Verizon
A. Wang
China Telecom
X. Liu
IBM Corporation
L. Liu
Fujitsu
23 October 2022
PCE for Mirror Binding
draft-chen-pce-mbinding-00
Abstract
PCE is used to distribute a binding SID with a list of SIDs to a
node. This document describes extensions to PCEP 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. Terminologies . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Extensions to PCEP . . . . . . . . . . . . . . . . . . . . . 3
3.1. Capability of distributing Binding for Protection . . . . 3
3.2. Extensions to RP/SRP Object . . . . . . . . . . . . . . . 5
4. Procedure for Updating Information . . . . . . . . . . . . . 6
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
5.1. Normative References . . . . . . . . . . . . . . . . . . 7
5.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
[I-D.ietf-pce-binding-label-sid] specifies how PCE 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 PCE 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 PCEP for distributing the information.
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2. Terminologies
The following terminologies are used in this document.
PCE: Path Computation Element
PCEP: PCE communication Protocol
PCC: Path Computation Client
3. Extensions to PCEP
A PCC may run on each of the nodes of a network. A PCE runs on a
server as a controller to communicate with PCCs. The PCE and the
PCCs work together to distribute the information about a binding SID
on a node to each neighbor of the node for protecting the binding SID
of the node when the node fails.
3.1. Capability of distributing Binding for Protection
When a PCE and a PCC running on a network node establish a PCEP
session between them, they exchange their capabilities of
distributing Binding for Binding SID Protection in Open messages. An
Open message includes an Open object. The object contains a
PATH_SETUP_TYPE_CAPABILITY TLV with Path Setup Type (PST) = TBD1 and
a new sub-TLV, called Binding SID (BSID) Distribution for Protection
Capability (BSID-D for short) sub-TLV.
PST = TBD1 indicates that Binding SID with List of SIDs (path) for a
node for protecting binding SID of the node.
BSID-D sub-TLV contains parameters used for distributing the
information about a binding SID for protection.
The format of BSID-D sub-TLV is shown in Figure 1.
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 = TBD2 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: BSID_DISTRIBUTION_PROTECTION_CAPABILITY sub-TLV
Type: TBD2 is to be assigned by IANA.
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Length: 4.
Reserved: 2 octets. Must be set to zero in transmission and ignored
on reception.
Flags: 2 octets. No flag bits are defined.
A PCC, which supports the capability of distributing Binding for
Protection, sends a PCE an Open message containing a
PATH_SETUP_TYPE_CAPABILITY TLV with Path Setup Type (PST) = TBD1 and
a BSID_DISTRIBUTION_PROTECTION_CAPABILITY sub-TLV. PST = TBD1
indicates that the PCC is capable of receiving and processing the
information about a binding SID on a node from the PCE for protecting
the binding SID of the node when the node fails.
A PCE, which supports the capability of distributing Binding for
Protection, sends a PCC an Open message containing a
PATH_SETUP_TYPE_CAPABILITY TLV with Path Setup Type (PST) = TBD1 and
a BSID_DISTRIBUTION_PROTECTION_CAPABILITY sub-TLV. PST = TBD1
indicates that the PCE is capable of sending the information about a
binding SID on a node to the PCC for protecting the binding SID of
the node when the node fails.
If both a PCC and a PCE support the capability of distributing
Binding for Protection, each of the Open messages sent by the PCC and
PCE contains a PATH-SETUP-TYPE-CAPABILITY TLV with a PST list
containing PST = TBD1 and a BSID_DISTRIBUTION_PROTECTION_CAPABILITY
sub-TLV.
If a PCE receives an Open message without a PATH-SETUP-TYPE-
CAPABILITY TLV containing PST = TBD1 from a PCC, then the PCE MUST
not send the PCC any information about a binding SID on a node for
protecting the binding SID of the node when the node fails.
If a PCC receives an Open message without a PATH-SETUP-TYPE-
CAPABILITY TLV containing PST = TBD1 from a PCE, then the PCC MUST
ignore any information about a binding SID on a node for protecting
the binding SID of the node from the PCE.
When PCECC is used, a PCC and PCE exchange capability of distributing
Binding SID for Binding SID protection using PCECC-CAPABILITY Sub-TLV
which is included in the PATH_SETUP_TYPE_CAPABILITY TLV in an Open
message.
A new flag bit B is defined in the Flags field of the PCECC-
CAPABILITY sub-TLV as shown in Figure 2. B flag (for Binding SID
Protection): if set to 1 by a PCEP speaker (PCE or PCC), the B flag
indicates that the PCEP speaker supports and is willing to handle the
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PCECC based central controller instructions for Binding SID
protection. The bit MUST be set to 1 by both a PCC and a PCE for the
PCECC Binding SID protection instruction download/report on a PCEP
session.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags |B|L|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: PCECC-Capability sub-TLV with B
3.2. Extensions to RP/SRP Object
After sending the binding information to a node (i.e., the PCC
running on the node), a PCE sends the corresponding binding
protection information to each neighbor of the node in a PCEP message
such as a Path Computation LSP Update Request (PCUpd) message. The
message contains a Request Parameters (RP) object or Stateful PCE
Request Parameters (SRP) object. The object includes:
* A PATH-SETUP-TYPE TLV with PST = TBD1 for Binding SID with List of
SIDs (path) for a node for protecting binding SID of the node.
* A Node ID TLV containing the identifier of the node.
The format of PATH-SETUP-TYPE TLV is shown in Figure 3.
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 = 28 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | PST = TBD1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: PATH-SETUP-TYPE TLV with PST = TBD1
The format of Node ID TLV is illustrated in Figure 4.
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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 = TBDa | Length (4/6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Node ID (4/6 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Node ID sub-TLV Format
Type: Its value (TBDa) is to be assigned by IANA.
Length: Its value (4/6) indicates the length of the value field of
the TLV is 4/6.
Node ID: 4/6-octet field contains the OSPF/IS-IS node (or router)
identifier (ID) of the (protected) node.
4. Procedure for Updating Information
When a PCE sends a piece of binding information to node N (i.e., PCC
running on N) in a first Path Computation LSP Update Request (PCUpd)
message, the PCE sends the corresponding binding protection
information to each neighbor of node N in a second PCUpd message.
The first message contains an RP/SRP object and an LSP object with a
TE-PATH-BINDING TLV. The RP/SRP object does not include any PATH-
SETUP-TYPE TLV with PST = TBD1. The TLV includes a binding SID and R
bit set to zero.
The second message contains an RP/SRP object and an LSP object with a
TE-PATH-BINDING TLV. The RP/SRP object includes a PATH-SETUP-TYPE
TLV with PST = TBD1 and a Node ID TLV indicating node N. TE-PATH-
BINDING TLV includes the binding SID and R bit set to zero.
After a PCE sends the binding information to node N, if the PCE
removes the binding information from node N through sending a third
PCUpd message to node N, the PCE removes the corresponding binding
protection information from each neighbor of node N through sending a
fourth PCUpd message to the neighbor.
The third message contains an RP/SRP object and an LSP object with a
TE-PATH-BINDING TLV. The RP/SRP object does not include any PATH-
SETUP-TYPE TLV with PST = TBD1. The TLV includes a binding SID and R
bit set to one (1).
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The fourth message contains an RP/SRP object and an LSP object with a
TE-PATH-BINDING TLV. The RP/SRP object includes a PATH-SETUP-TYPE
TLV with PST = TBD1 and a Node ID TLV indicating node N. TE-PATH-
BINDING TLV includes the binding SID and R bit set to one (1).
After a PCE sends the binding information to node N, if the PCE
changes the binding information in node N through sending a fifth
PCUpd message to node N, the PCE changes the corresponding binding
protection information in each neighbor of node N through sending a
sixth PCUpd message to the neighbor.
The fifth message contains an RP/SRP object and an LSP object with a
TE-PATH-BINDING TLV. The RP/SRP object does not include any PATH-
SETUP-TYPE TLV with PST = TBD1. The LSP object includes a (changed)
path. The TLV includes a binding SID and R bit set to zero.
The sixth message contains an RP/SRP object and an LSP object with a
TE-PATH-BINDING TLV. The RP/SRP object includes a PATH-SETUP-TYPE
TLV with PST = TBD1 and a Node ID TLV indicating node N. The LSP
object includes the (changed) path. TE-PATH-BINDING TLV includes the
binding SID and R bit set to zero.
5. References
5.1. 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>.
5.2. Informative References
[I-D.ietf-pce-binding-label-sid]
Sivabalan, S., Filsfils, C., Tantsura, J., Previdi, S.,
and C. L. (editor), "Carrying Binding Label/Segment
Identifier (SID) in PCE-based Networks.", Work in
Progress, Internet-Draft, draft-ietf-pce-binding-label-
sid-15, 20 March 2022, <https://www.ietf.org/archive/id/
draft-ietf-pce-binding-label-sid-15.txt>.
Authors' Addresses
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Huaimo Chen
Futurewei
Boston, MA,
United States of America
Email: huaimo.chen@futurewei.com
Bruno Decraene
Orange
France
Email: bruno.decraene@orange.com
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
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
Lei Liu
Fujitsu
United States of America
Email: liulei.kddi@gmail.com
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