PCE Working Group H. Ananthakrishnan
Internet-Draft Packet Design
Intended status: Standards Track S. Sivabalan
Expires: July 13, 2017 Cisco
C. Barth
R. Torvi
Juniper Networks
I. Minei
Google, Inc
E. Crabbe
January 9, 2017
PCEP Extensions for MPSL-TE LSP Path Protection with stateful PCE
draft-ananthakrishnan-pce-stateful-path-protection-02
Abstract
A stateful Path Computation Element (PCE) is capable of computing as
well as controlling via Path Computation Element Protocol (PCEP)
Multiprotocol Label Switching Traffic Engineering Label Switched
Paths (MPLS LSP). Furthermore, it is also possible for a stateful
PCE to create, maintain, and delete LSPs. This document describes
PCEP extension to associate two or more LSPs to provide end-to-end
path protection.
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
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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 July 13, 2017.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://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 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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. PCEP Extensions . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Path Protection Association Type . . . . . . . . . . . . 4
3.2. Path Protection Association TLV . . . . . . . . . . . . . 5
4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. PCE Initiated LSPs . . . . . . . . . . . . . . . . . . . 6
4.2. PCC Initiated LSPs . . . . . . . . . . . . . . . . . . . 6
4.3. State Synchronization . . . . . . . . . . . . . . . . . . 7
4.4. Error Handling . . . . . . . . . . . . . . . . . . . . . 7
5. IANA considerations . . . . . . . . . . . . . . . . . . . . . 7
5.1. Association Type . . . . . . . . . . . . . . . . . . . . 7
5.2. PPAG TLV . . . . . . . . . . . . . . . . . . . . . . . . 7
5.3. PCEP Errors . . . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
8.1. Normative References . . . . . . . . . . . . . . . . . . 9
8.2. Information References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
[RFC5440] describes PCEP for communication between a Path Computation
Client (PCC) and a PCE or between one a pair of PCEs. A PCE computes
paths for MPLS-TE LSPs based on various constraints and optimization
criteria.
Stateful pce [I-D.ietf-pce-stateful-pce] specifies a set of
extensions to PCEP to enable stateful control of paths such as MPLS
TE LSPs between and across PCEP sessions in compliance with
[RFC4657]. It includes mechanisms to effect LSP state
synchronization between PCCs and PCEs, delegation of control of LSPs
to PCEs, and PCE control of timing and sequence of path computations
within and across PCEP sessions and focuses on a model where LSPs are
configured on the PCC and control over them is delegated to the PCE.
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Furthermore, a mechanism to dynamically instantiate LSPs on a PCC
based on the requests from a stateful PCE or a controller using
stateful PCE is specified in [I-D.ietf-pce-pce-initiated-lsp].
Path protection refers to a paradigm in which the working LSP is
protected by one or more protection LSP(s). When the working LSP
fails, protection LSP(s) is/are activated. When the working LSPs are
computed and controlled by the PCE, there is benefit in a mode of
operation where protection LSPs are as well.
This document specifies a stateful PCEP extension to associate two or
more LSPs for the purpose of setting up path protection. The
proposed extension covers the following scenarios:
1. A protection LSP is initiated on a PCC by a stateful PCE which
retains the control of the LSP. The PCE is responsible for
computing the path of the LSP and updating the PCC with the
information about the path.
2. A PCC initiates a protection LSP and retains the control of the
LSP. The PCC computes the path and updates the PCE with the
information about the path as long as it controls the LSP.
3. A PCC initiates a protection LSP and delegates the control of the
LSP to a stateful PCE. The PCE may compute the path for the LSP
and update the PCC with the information about the path as long as
it controls the LSP.
Note that protection LSP can be established prior to the failure (in
which case the LSP is said to me in standby mode) or post failure of
the corresponding working LSP according to the operator choice/
policy.
2. Terminology
The following terminologies are used in this document:
AGID: Association Group ID.
ERO: Explicit Route Object.
LSP: Label Switched Path.
PCC: Path Computation Client.
PCE: Path Computation Element
PCEP: Path Computation Element Protocol.
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PPAG: Path Protection Association Group.
TLV: Type, Length, and Value.
3. PCEP Extensions
3.1. Path Protection Association Type
LSPs are not associated by listing the other LSPs with which they
interact, but rather by making them belong to an association group
referred to as "Path Protection Association Group" (PPAG) in this
document. All LSPs join a PPAG individually. PPAG is based on the
generic Association object used to associate two or more LSPs
specified in [I-D.ietf-pce-association-group]. A member of a PPAG
can take the role of working or protection LSP. This document
defines a new association type called "Path Protection Association
Type" of value TBD1. A PPAG can have one working LSP and/or one or
more protection LSPs. The source and destination of all LSPs within
a PPAG MUST be the same.
The format of the Association object used for PPAG is specified in
[I-D.ietf-pce-association-group] and replicatd in this document for
easy reference in Figure 1 and Figure 2.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Association type = TBD1 | Association |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Association Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Optional TLVs //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: PPAG IPv4 ASSOCIATION Object format
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Association Type = TBD1 | Association |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IPv6 Association Source |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Optional TLVs //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: PPAG IPv6 ASSOCIATION Object format
This document defines a new Association type, the Path Protection
Association type, value will be assigned by IANA (TBD1).
3.2. Path Protection Association TLV
The Path Protection Association TLV is an optional TLV for use with
the Path Protection Association Object Type. The Path Protection
Association TLV MUST NOT be present more than once. If it appears
more than once, only the first occurrence is processed and any others
MUST be ignored.
The Path Protection Association TLV follows the PCEP TLV format of
[RFC5440].
The type (16 bits) of the TLV is to be assigned by IANA. The length
field is 16 bit-long and has a fixed value of 4.
The value comprises a single field, the Path Protection Association
Flags (32 bits), where each bit represents a flag option.
The format of the Path Protection Association TLV (Figure 3) is as
follows:
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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 = TBD2 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Path Protection Association Flags |S|P|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Path Protection Association TLV format
P (PROTECTION-LSP 1 bit) - Indicates whether the LSP associated with
the PPAG is working or protection LSP. If this flag is set, the LSP
is a protection LSP.
S (STANDBY 1 bit)- When the P flag is set, the S flag indcates
whether the protection LSP associated with the PPAG is in standby
mode. The S flag is ignored if the P flag is not set.
If the Path Protection Association TLV is missing, it means the LSP
is the working LSP.
4. Operation
4.1. PCE Initiated LSPs
A PCE can create/update working and protection LSPs independently.
As specified in [I-D.ietf-pce-association-group], Association Groups
can be created by both PCE and PCC.
A PCE can remove a protection LSP from a PPAG as specified in
[I-D.ietf-pce-association-group].
4.2. PCC Initiated LSPs
A PCC can associate a set of LSPs under its control for path
protection purpose. Similarly, the PCC can remove on or more LSPs
under its control from the corresponding PPAG. In both cases, the
PCC must report the change in association to PCE(s) via PCRpt
message.
A stateless PCC can request protection to a PCE thorugh PCReq
message.
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4.3. State Synchronization
During state synchronization, a PCC MUST report all the existing path
protection association groups as well as any path protection flags to
PCE(s). Following the state synchronization, the PCE MUST remove all
stale path protection associations.
4.4. Error Handling
All LSPs (working or protection) within a PPAG MUST have the same
source and destination. If a PCE attempts to add an LSP to a PPAG
and the source and/or destination of the LSP is/are different from
the LSP(s) in the PPAG, the PCC MUST send PCErr with Error-Type= TBD3
(Path Protection Association Error) and Error-Value = 1 (End points
mismatch).
There MUST be only one working LSP within a PPAG. If a PCEP Speaker
attempts to add another working LSP, the PCEP peer MUST send PCErr
with Error-Type=TBD3(Path Protection Association Error) and Error-
Value = 2 (Attempt to add another working LSP).
5. IANA considerations
5.1. Association Type
This document defines a new association type for path protection as
follows:
+-------------------------+-------------------------+---------------+
| Association Type Value | Association Name | Reference |
+-------------------------+-------------------------+---------------+
| TBD1 (Suggested value - | Path Protection | This |
| 1) | Association | document |
+-------------------------+-------------------------+---------------+
5.2. PPAG TLV
This document defines a new TLV for carrying additional information
of LSPs within a path protection association group as follows:
+-----------------------+-----------------------------+-------------+
| TLV Type Value | TLV Name | Reference |
+-----------------------+-----------------------------+-------------+
| TBD2 (suggested Value | Path Protection Association | This |
| - 29) | Group TLV | document |
+-----------------------+-----------------------------+-------------+
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This document requests that a new sub-registry, named "Path
protection Association Group TLV Flag Field", is created within the
"Path Computation Element Protocol (PCEP) Numbers" registry to manage
the Flag field in the Path Protection Association Group TLV. New
values are to be assigned by Standards Action [RFC5226]. Each bit
should be tracked with the following qualities:
Each bit should be tracked with the following qualities:
o Bit number (count from 0 as the most significant bit)
o Name flag
o Reference
+------------+--------------------+----------------+
| Bit Number | Name | Reference |
+------------+--------------------+----------------+
| 31 | P - PROTECTION-LSP | This document |
| 30 | S - STANDBY | This document |
+------------+--------------------+----------------+
Table 1: PPAG TLV
5.3. PCEP Errors
This document defines new Error-Type and Error-Value related to path
protection association as follows:
+-------------------------+-----------------------------------------+
| Error-Type | Meaning |
+-------------------------+-----------------------------------------+
| TBD3 (suggested value - | Path Protection Association error: |
| 25) | |
| | Error-value=1: End-Points mismatch |
| | Error-value=2: Attempt to add another |
| | working LSP |
+-------------------------+-----------------------------------------+
6. Security Considerations
The same security considerations apply in head end as described in
[I-D.ietf-pce-pce-initiated-lsp]
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7. Acknowledgments
We would like to thank Jeff Tantsura, Dhruv Dhody and Zhangxian for
their contributions to this document.
8. References
8.1. Normative References
[I-D.ietf-pce-association-group]
Minei, I., Crabbe, E., Sivabalan, S., Ananthakrishnan, H.,
Zhang, X., and Y. Tanaka, "PCEP Extensions for
Establishing Relationships Between Sets of LSPs", draft-
ietf-pce-association-group-01 (work in progress), July
2016.
[I-D.ietf-pce-pce-initiated-lsp]
Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "PCEP
Extensions for PCE-initiated LSP Setup in a Stateful PCE
Model", draft-ietf-pce-pce-initiated-lsp-07 (work in
progress), July 2016.
[I-D.ietf-pce-stateful-pce]
Crabbe, E., Minei, I., Medved, J., and R. Varga, "PCEP
Extensions for Stateful PCE", draft-ietf-pce-stateful-
pce-18 (work in progress), December 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, DOI 10.17487/RFC2205,
September 1997, <http://www.rfc-editor.org/info/rfc2205>.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<http://www.rfc-editor.org/info/rfc3209>.
[RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast
Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
DOI 10.17487/RFC4090, May 2005,
<http://www.rfc-editor.org/info/rfc4090>.
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[RFC5088] Le Roux, JL., Ed., Vasseur, JP., Ed., Ikejiri, Y., and R.
Zhang, "OSPF Protocol Extensions for Path Computation
Element (PCE) Discovery", RFC 5088, DOI 10.17487/RFC5088,
January 2008, <http://www.rfc-editor.org/info/rfc5088>.
[RFC5089] Le Roux, JL., Ed., Vasseur, JP., Ed., Ikejiri, Y., and R.
Zhang, "IS-IS Protocol Extensions for Path Computation
Element (PCE) Discovery", RFC 5089, DOI 10.17487/RFC5089,
January 2008, <http://www.rfc-editor.org/info/rfc5089>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<http://www.rfc-editor.org/info/rfc5440>.
[RFC5511] Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax
Used to Form Encoding Rules in Various Routing Protocol
Specifications", RFC 5511, DOI 10.17487/RFC5511, April
2009, <http://www.rfc-editor.org/info/rfc5511>.
8.2. Information References
[RFC2702] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M., and J.
McManus, "Requirements for Traffic Engineering Over MPLS",
RFC 2702, DOI 10.17487/RFC2702, September 1999,
<http://www.rfc-editor.org/info/rfc2702>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001,
<http://www.rfc-editor.org/info/rfc3031>.
[RFC3346] Boyle, J., Gill, V., Hannan, A., Cooper, D., Awduche, D.,
Christian, B., and W. Lai, "Applicability Statement for
Traffic Engineering with MPLS", RFC 3346,
DOI 10.17487/RFC3346, August 2002,
<http://www.rfc-editor.org/info/rfc3346>.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630,
DOI 10.17487/RFC3630, September 2003,
<http://www.rfc-editor.org/info/rfc3630>.
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[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006,
<http://www.rfc-editor.org/info/rfc4655>.
[RFC4657] Ash, J., Ed. and J. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol Generic
Requirements", RFC 4657, DOI 10.17487/RFC4657, September
2006, <http://www.rfc-editor.org/info/rfc4657>.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, DOI 10.17487/RFC5305, October
2008, <http://www.rfc-editor.org/info/rfc5305>.
[RFC5394] Bryskin, I., Papadimitriou, D., Berger, L., and J. Ash,
"Policy-Enabled Path Computation Framework", RFC 5394,
DOI 10.17487/RFC5394, December 2008,
<http://www.rfc-editor.org/info/rfc5394>.
[RFC5557] Lee, Y., Le Roux, JL., King, D., and E. Oki, "Path
Computation Element Communication Protocol (PCEP)
Requirements and Protocol Extensions in Support of Global
Concurrent Optimization", RFC 5557, DOI 10.17487/RFC5557,
July 2009, <http://www.rfc-editor.org/info/rfc5557>.
Authors' Addresses
Hariharan Ananthakrishnan
Packet Design
1 South Almaden Blvd, #1150,
San Jose, CA, 95113
USA
EMail: hari@packetdesign.com
Siva Sivabalan
Cisco
2000 Innovation Drive
Kananta, Ontaria K2K 3E8
Cananda
EMail: msiva@cisco.com
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Colby Barth
Juniper Networks
1194 N Mathilda Ave,
Sunnyvale, CA, 94086
USA
EMail: cbarth@juniper.net
Raveendra Torvi
Juniper Networks
1194 N Mathilda Ave,
Sunnyvale, CA, 94086
USA
EMail: rtorvi@juniper.net
Ina Minei
Google, Inc
1600 Amphitheatre Parkway
Mountain View, CA, 94043
USA
EMail: inaminei@google.com
Edward Crabbe
EMail: edward.crabbe@gmail.com
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