Internet Engineering Task Force S. Alvarez
Internet-Draft S. Sivabalan
Intended status: Standards Track Z. Ali
Expires: August 18, 2014 Cisco Systems, Inc.
L. Tomotaki
Verizon
V. Lopez
Telefonica I+D
February 14, 2014
PCE Path Profiles
draft-alvarez-pce-path-profiles-01
Abstract
This document describes extensions to the Path Computation Element
(PCE) Communication Protocol (PCEP) to signal path profile
identifiers. A profile represents a list of path parameters or
policies that a PCEP peer may invoke on a remote peer using an opaque
identifier. When a path computation client (PCC) initiates a path
computation request, the PCC can signal profile identifiers to invoke
path parameters or policies defined on the PCE which would influence
the path computation. Similarly, when a PCE initiates or updates a
path, the PCE can signal profile identifiers to invoke path
parameters or policies defined on the PCC which would influence the
path setup.
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
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 18, 2014.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Path Profiles . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Capability Advertisement . . . . . . . . . . . . . . . . 3
3.2. PCC-Initiated Paths . . . . . . . . . . . . . . . . . . . 3
3.2.1. Point-to-Point Paths . . . . . . . . . . . . . . . . 4
3.2.2. Point-to-Multipoint Paths . . . . . . . . . . . . . . 5
3.3. PCE-Initiated Paths . . . . . . . . . . . . . . . . . . . 5
4. Object Extensions . . . . . . . . . . . . . . . . . . . . . . 6
4.1. OPEN Object . . . . . . . . . . . . . . . . . . . . . . . 6
4.2. PATH-PROFILE Object . . . . . . . . . . . . . . . . . . . 7
5. Error Codes for PATH-PROFILE Object . . . . . . . . . . . . . 8
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8. Security Considerations . . . . . . . . . . . . . . . . . . . 8
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
1.1. 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].
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2. Path Profiles
A path profile represents a list of path parameters or policies that
a PCEP peer may invoke on a remote peer using a profile identifier.
The receiving peer interprets the identifier according to a local
path profile definition. The PATH-PROFILE object defined in
Section 4.2 can signal one or more profile identifiers. PCEP carries
profile identifiers as opaque values. PCEP peers do not exchange the
details of a path profile. The PCE may be stateful or stateless.
3. Procedures
3.1. Capability Advertisement
PCEP peers advertise their capability to support path profile
identifiers during the session initialization phase. They include
the PATH-PROFILE-CAPABILITY TLV defined in Section 4.1 as part of the
OPEN object. A PCEP peer can only signal path profile identifiers if
both peers advertised this capability. A peer MUST send a PCErr
message with Error-Type=4 (Not supported object), Error-value=1 (Not
supported object class) and close the session if it receives a
message with a path profile identifier, it supports the extensions in
this document and both peers did not advertise this capability.
3.2. PCC-Initiated Paths
A PCC MAY include a PATH-PROFILE object when sending a PCReq message.
The PCE uses the path profile identifier to select path parameters or
path policies to fulfill the request. The means by which the PCC
learns about a particular path profile identifier and decides to
include it in a PCReq message are outside the scope of this document.
Similarly, the means by which the PCE selects a set of parameters or
policies based on the profile identifier for a specific request are
outside the scope of this document. The P flag of the PATH-PROFILE
object MUST be set.
A PCE may receive a path computation request with an unknown or
invalid path profile identifier. The PCE sends a PCErr message with
Error-Type=[TBA] (PATH-PROFILE Error), Error-value=1 (Unknown path
profile) if the path profile identifier is not known to the PCE. The
PCE sends a PCErr message with Error-Type=[TBA] (PATH-PROFILE Error),
Error-value=2 (Invalid path profile) if the PCE knows about the path
profile identifier, but considers the request invalid. As an
example, the profile may be invalid because of the path type, the
PCEP session type or the originating PCC. The PCEP-ERROR object
SHOULD include the path profile identifiers that generated the error
condition.
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The PCE will determine whether to consider any additional optional
objects included in a PCReq message based on policy. As illustrated
in Section 3.2.1 and Section 3.2.2, the PCC MAY include other
optional objects along with a PATH-PROFILE object as part of a path
computation request. The PCC will use the processing-rule (P) flag
in the common object header to signal whether it considers those
objects mandatory or optional when the PCE performs path computation.
Those objects may overlap with the path parameters that the PCE
associates with the path profile identifier.
PCE policy may place different kinds of restrictions on PCReq
messages that include a PATH-PROFILE object and additional
parameters. A PCE MUST send an error message if it receives a
request with optional objects signaled as mandatory (P flag = 1) for
path computation and PCE policy does not allow such behavior from the
originating PCC. In that case, the PCE sends a PCErr message with
Error-Type=[TBA] (PATH-PROFILE Error), Error-value=3 (Unexpected
mandatory object). If the objects are signaled as optional (P flag =
0) for path computation, the PCE will decide based on policy whether
to consider them or not. When sending the PCRep message for the
request, the PCE will use the ignore (I) flag in the common object
header to indicate to the PCC whether an object was ignored.
3.2.1. Point-to-Point Paths
[RFC5440] defines the basic structure of a PCReq message for point-
to-point paths. This documents extends the message format as
follows:
<PCReq Message>::= <Common Header>
[<svec-list>]
<request-list>
where:
<svec-list>::=<SVEC>[<svec-list>]
<request-list>::=<request>[<request-list>]
<request>::= <RP>
<END-POINTS>
[<PATH-PROFILE>]
[<path-computation>]
where:
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<path-computation> is the list of optional objects used for path
computation as defined initially in [RFC5440] and modified in
subsequent PCEP extensions.
If present in a PCReq message, the PATH-PROFILE object MUST be the
first optional object in the request portion of the message.
3.2.2. Point-to-Multipoint Paths
[RFC6006] defines the basic structure of a PCReq message for point-
to-multipoint paths. This documents extends the message format as
follows:
TBD
3.3. PCE-Initiated Paths
A PCE MAY include a PATH-PROFILE object when sending a PCInitiate
message as defined in [I-D.ietf-pce-pce-initiated-lsp]. The PCC uses
the path profile identifier to select path parameters or path
policies to be applied during the instantiation of the path. The
means by which the PCE learns about a particular path profile
identifier and decides to include it in a PCInitiate message are
outside the scope of this document. Similarly, the means by which
the PCC selects a set of parameters or policies based on the profile
identifier for a specific path are outside the scope of this
document.
A PCC may receive a path instantiation request with an unknown or
invalid path profile identifier. The PCC sends a PCErr message with
Error-Type=[TBA] (PATH-PROFILE Error), Error-value=1 (Unknown path
profile) if the path profile identifier is not known to the PCC. The
PCC sends a PCErr message with Error-Type=[TBA] (PATH-PROFILE Error),
Error-value=2 (Invalid path profile) if the PCC knows about the path
profile identifier, but considers the request invalid. As an
example, the profile may be invalid because of the path type, the
PCEP session type or the originating PCE. The PCEP-ERROR object
SHOULD include the path profile identifiers that generated the error
condition.
[I-D.ietf-pce-pce-initiated-lsp] defines the basic structure of a
PCInitiate message. This documents extends the message format as
follows:
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<PCInitiate Message> ::= <Common Header>
<PCE-initiated-lsp-list>
Where:
<PCE-initiated-lsp-list> ::= <PCE-initiated-lsp-request>
[<PCE-initiated-lsp-list>]
<PCE-initiated-lsp-request> ::= (<PCE-initiated-lsp-instantiation>|
<PCE-initiated-lsp-deletion>)
<PCE-initiated-lsp-instantiation> ::= <SRP>
<LSP>
<END-POINTS>
<ERO>
[PATH-PROFILE>
[<attribute-list>]
<PCE-initiated-lsp-deletion> ::= <SRP>
<LSP>
where:
<attribute-list> is defined in [RFC5440] and extended by PCEP
extensions.
4. Object Extensions
4.1. OPEN Object
This documents defines a new optional PATH-PROFILE-CAPABILITY TLV in
the OPEN object.
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=[TBA] | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
PATH-PROFILE-CAPABILITY TLV
Figure 1
Reserved (16 bits):
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MUST be set to zero on transmission and ignored on receipt.
Flags (16 bits):
Unassigned bits are considered reserved. They MUST be set to zero
on transmission and ignored on receipt. No flags are currently
defined.
4.2. PATH-PROFILE Object
The PATH-PROFILE object may be carried in PCReq, PCInitiate and PCUpd
messages.
PATH-PROFILE Object-Class is [TBA].
PATH-PROFILE Object-Type is 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// TLVs //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
PATH-PROFILE Object
Figure 2
The PATH-PROFILE object has a variable length and contains one or
more PATH-PROFILE-ID TLVs.
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=[TBD] | Length=6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags | Path Profile Id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Path Profile Id (cont) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
PATH-PROFILE-ID TLV
Figure 3
Reserved (8 bits):
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MUST be set to zero on transmission and ignored on receipt.
Flags (8 bits):
Unassigned bits are considered reserved. They MUST be set to zero
on transmission and ignored on receipt. No flags are currently
defined.
Path Profile Id (32 bits):
(non-zero) unsigned path profile identifier.
5. Error Codes for PATH-PROFILE Object
Error-Type Meaning Error-Value
<TBA> PATH-PROFILE Error 1: Unknown path profile
2: Invalid path profile
3: Unexpected mandatory object
6. Acknowledgements
The authors would like to thank Clarence Filsfils for his valuable
comments.
7. IANA Considerations
IANA is requested to assign the following code points.
PATH-PROFILE-CAPABILITY TLV
PATH-PROFILE Object-Class
PATH-PROFILE Object-Type
PATH-PROFILE Error-Type
8. Security Considerations
TBD
9. References
9.1. Normative References
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[I-D.ali-pce-remote-initiated-gmpls-lsp]
Ali, Z., Sivabalan, S., Filsfils, C., Varga, R., Lopez,
V., Dios, O., and X. Zhang, "Path Computation Element
Communication Protocol (PCEP) Extensions for remote-
initiated GMPLS LSP Setup", draft-ali-pce-remote-
initiated-gmpls-lsp-02 (work in progress), October 2013.
[I-D.ietf-pce-gmpls-pcep-extensions]
Margaria, C., Dios, O., and F. Zhang, "PCEP extensions for
GMPLS", draft-ietf-pce-gmpls-pcep-extensions-08 (work in
progress), July 2013.
[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-00 (work in
progress), December 2013.
[I-D.ietf-pce-stateful-pce]
Crabbe, E., Medved, J., Minei, I., and R. Varga, "PCEP
Extensions for Stateful PCE", draft-ietf-pce-stateful-
pce-07 (work in progress), October 2013.
[I-D.sivabalan-pce-segment-routing]
Sivabalan, S., Medved, J., Filsfils, C., Crabbe, E., and
R. Raszuk, "PCEP Extensions for Segment Routing", draft-
sivabalan-pce-segment-routing-02 (work in progress),
October 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element
(PCE) Communication Protocol (PCEP)", RFC 5440, March
2009.
[RFC6006] Zhao, Q., King, D., Verhaeghe, F., Takeda, T., Ali, Z.,
and J. Meuric, "Extensions to the Path Computation Element
Communication Protocol (PCEP) for Point-to-Multipoint
Traffic Engineering Label Switched Paths", RFC 6006,
September 2010.
9.2. Informative References
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006.
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Authors' Addresses
Santiago Alvarez
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134
USA
Email: saalvare@cisco.com
Siva Sivabalan
Cisco Systems, Inc.
2000 Innovation Drive
Kanata, ON K2K-3E8
Canada
Email: msiva@cisco.com
Zafar Ali
Cisco Systems, Inc.
2000 Innovation Drive
Kanata, ON K2K-3E8
Canada
Email: zali@cisco.com
Luis Tomotaki
Verizon
400 International
Richardson, TX 75081
US
Email: luis.tomotaki@verizon.com
Victor Lopez
Telefonica I+D
c/ Don Ramon de la Cruz 84
Madrid 28006
Spain
Email: vlopez@tid.es
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