Diffserv-Aware Class-Type Object for the Path Computation Element Communication Protocol
draft-ietf-pce-dste-02
The information below is for an old version of the document that is already published as an RFC.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 5455.
|
|
|---|---|---|---|
| Authors | Kenji Kumaki , Jon Parker , Sami Boutros , Siva Sivabalan | ||
| Last updated | 2020-01-21 (Latest revision 2008-11-03) | ||
| Replaces | draft-sivabalan-pce-dste | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Proposed Standard | ||
| Formats | |||
| Reviews | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | (None) | |
| Document shepherd | (None) | ||
| IESG | IESG state | Became RFC 5455 (Proposed Standard) | |
| Action Holders |
(None)
|
||
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | Ross Callon | ||
| Send notices to | (None) |
draft-ietf-pce-dste-02
Network Working Group S. Sivabalan, Ed.
Internet Draft J. Parker
Intended status: Standards Track S. Boutros
Expires: May 2, 2009 Cisco Systems, Inc.
K. Kumaki
KDDI Corporation
November 3, 2008
Diff-Serv Aware Class Type Object for
Path Computation Element Communication Protocol
draft-ietf-pce-dste-02.txt
Status of this Memo
By submitting this Internet-Draft, each author represents that
any applicable patent or other IPR claims of which he or she is
aware have been or will be disclosed, and any of which he or she
becomes aware will be disclosed, in accordance with Section 6 of
BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html
This Internet-Draft will expire on May 2, 2009.
Copyright Notice
Copyright (C) The IETF Trust (2008).
Sivabalan Expires May 3, 2009 [Page 1]
Internet-Draft draft-ietf-pce-dste-02.txt November 2008
Abstract
This document specifies a CLASSTYPE object to support Diff-Serve
Aware Traffic Engineering (DS-TE) where path computation is performed
with an aid of Path Computation Element (PCE).
Conventions used in this document
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 Error!
Reference source not found..
Table of Contents
1. Introduction...................................................2
2. Terminology....................................................3
3. CLASSTYPE Object...............................................4
3.1. Object Definition.........................................4
3.2. Path Computation Request message with CLASSTYPE Object....4
3.3. Processing CLASSTYPE Object...............................5
3.4. Determination of Traffic Engineering Class (TE-Class).....6
3.5. Significance of Class-Type and TE-Class...................6
3.6. Error Codes for CLASSTYPE Object..........................6
4. Security Considerations........................................7
5. IANA Considerations............................................7
6. Acknowledgments................................................7
6.1. Normative References......................................8
6.2. Informative References....................................8
Author's Addresses................................................8
Intellectual Property Statement...................................9
Disclaimer of Validity............................................9
1. Introduction
The Internet Draft [PCEP-ID] specifies the Path Computation Element
communication Protocol (PCEP) for communications between a Path
Computation Client (PCC) and a Path Computation Element (PCE), or
between two PCEs, in compliance with [RFC4657].
Differentiated Service aware MPLS Traffic Engineering (DS-TE)
addresses the fundamental requirement to be able to enforce different
bandwidth constraints for different classes of traffic. It describes
mechanisms to achieve per-class traffic engineering, rather than on
an aggregate basis across all classes by enforcing Bandwidth
Constraints (BCs) on different classes. Requirements for DS-TE and
Sivabalan Expires May 3, 2009 [Page 2]
Internet-Draft draft-ietf-pce-dste-02.txt November 2008
the associated protocol extensions are specified in [RFC3564] and
[RFC4124] respectively.
As per [RFC4657], PCEP must support traffic class-type as an MPLS TE
specific constraint. However, in the present form, PCEP [PCEP-ID]
does not have the capability to specify the class-type in the path
computation request.
In this document, we define a new PCEP object called CLASSTYPE which
carries the class-type of the TE LSP in the path computation request.
During path computation, a PCE uses the class-type to identify the
bandwidth constraint of the TE-LSP.
2. Terminology
CT: Class type: A set of Traffic Trunks governed by a set of
bandwidth constraints. Used for the purpose of link bandwidth
allocation, constraint based routing and admission control. A given
Traffic Trunk belongs to the same CT on all links.
DS-TE: Diff-Serv Aware Traffic Engineering.
LSR: Label Switching Router.
LSP: Label Switched Path.
PCC: Path Computation Client: any client application requesting a
path computation to be performed by a Path Computation Element.
PCE: Path Computation Element: an entity (component, application or
network node) that is capable of computing a network path or route
based on a network graph and applying computational constraints.
PCEP Peer: an element involved in a PCEP session (i.e. a PCC or the
PCE).
TE-Class: A pair consisting of a class-type and a preemption priority
allowed for that class type. An LSP transporting a Traffic Trunk from
that class type can use that preemption priority as the setup
priority, the holding priority, or both.
TE LSP: Traffic Engineering Label Switched Path.
Traffic Trunk: An aggregation of traffic flows of the same class
(i.e. treated equivalently from the DS-TE perspective) which is
placed inside a TE LSP.
Sivabalan Expires May 3, 2009 [Page 3]
Internet-Draft draft-ietf-pce-dste-02.txt November 2008
3. CLASSTYPE Object
The CLASSTYPE object is optional and is used to specify the class-
type of a TE LSP. This object is meaningful only within the path
computation request, and is ignored in the path reply message. If the
TE LSP for which the path is to be computed belongs to Class 0, the
path computation request MUST NOT contain the CLASSTYPE object. This
allows backward compatibility with PCE that does not support the
CLASSTYPE object.
3.1. Object Definition
The CLASSTYPE object contains a 32-bit word PCEP common object header
defined in [PCEP-ID] followed by another 32-bit word object body as
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PCEP common header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | CT |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1 CLASSTYPE object format.
The fields in the object common header are processed as specified in
[PCEP-ID]. The values of object class and object type are 22 and 1
respectively. If included, CLASSTYPE object must be taken into
account by PCE. As such, the P flag MUST be set. I flag is ignored.
The CLASSTYPE object body contains the following fields:
CT: 3-bit field that indicates the class-type. Values allowed are 1,
2, ... , 7. Value of 0 is Reserved.
Reserved: 29-bit reserved field. It MUST be set to zero on
transmission and MUST be ignored on receipt.
3.2. Path Computation Request message with CLASSTYPE Object
[PCEP-ID] specifies the object orders in which objects must be
inserted in the PCEP messages. This document specifies that the
CLASSTYPE object be inserted after the END-POINT objects as shown
below:
The format of a PCReq message is as follows:
Sivabalan Expires May 3, 2009 [Page 4]
Internet-Draft draft-ietf-pce-dste-02.txt November 2008
<PCReq Message>::= <Common Header>
[<SVEC-list>]
<request-list>
where:
<svec-list>::=<SVEC>[<svec-list>]
<request-list>::=<request>[<request-list>]
<request>::= <RP>
<END-POINTS>
[<CLASSTYPE>]
[<LSPA>]
[<BANDWIDTH>]
[<metric-list>]
[<RRO>]
[<IRO>]
[<LOAD-BALANCING>]
where:
<metric-list>::=<METRIC>[<metric-list>]
Note that an implementation MUST form the PCEP messages using the
object ordering rules specified using Backus-Naur Form. Please refer
[OBJ-ORD] for more details.
3.3. Processing CLASSTYPE Object
If the LSP is associated with Class-Type N (1 <= N <= 7), the PCC
originating the path computation request MUST include the CLASSTYPE
object in the Path computation request message with the Class-Type
(CT) field set to N.
If a path computation request contains multiple CLASSTYPE objects,
only the first one is meaningful; subsequent CLASSTYPE object(s) MUST
be ignored and MUST NOT be forwarded.
If the CLASSTYPE object is not present in the path computation
request message, the LSR MUST associate the Class-Type 0 to the LSP.
Path computation reply message MUST NOT include a CLASSTYPE object.
If a PCE needs to forward a path computation request containing the
CLASSTYPE object to another PCE, it MUST store the class-type of the
TE LSP in order to complete the path computation when the path
computation reply arrives.
A PCE that does not recognize the CLASSTYPE object MUST reject the
entire PCEP message and MUST send a PCE error message with Error-
Type="Unknown Object" or "Not supported Object" defined in [PCEP-ID].
Sivabalan Expires May 3, 2009 [Page 5]
Internet-Draft draft-ietf-pce-dste-02.txt November 2008
A PCE that recognizes the CLASSTYPE object finds that P flag is not
set in the CLASSTYPE object, it MUST send PCE error message towards
the sender with the with the error type and error value specified in
[PCEP-ID].
A PCE that recognizes the CLASSTYPE object, but does not support the
particular Class-Type, MUST send a PCE error message towards the
sender with the error type "Diff-Serv aware TE Error" and the error
value of "Unsupported Class-Type" (new error code provided below).
A PCE that recognizes the CLASSTYPE object, but determines that the
Class-Type value is not valid (i.e., Class Type value 0), MUST send a
PCE error towards the sender with the error type "Diff-Serve aware TE
Error" and an error value of "Invalid Class-Type value" (new error
code provided below).
3.4. Determination of Traffic Engineering Class (TE-Class)
As specified in RFC4124, a CT and a Preemption priority map to a
Traffic Engineering Class (TE-Class), and there can be up to 8 TE-
classes. The TE-class value is used to determine the unreserved
bandwidth on the links during path computation. In the case of a PCE,
the CT value carried in the CLASSTYPE object and the setup priority
in the LSP Attribute (LSPA) object are used to determine the TE-class
corresponding to the path computation request. If LSPA object is
absent, the setup priority is assumed to be 0.
3.5. Significance of Class-Type and TE-Class
To ensure coherent DS-TE operation, a PCE and a PCC should have a
common understanding of a particular DS-TE classtype and TE-Class.
If a path computation request crosses an AS boundary, these should
have global significance in all domains. Enforcement of this global
significance is outside the scope of this document.
3.6. Error Codes for CLASSTYPE Object
This document defines the following error type and values:
Error-Type Meaning
12 Diff-Serve aware TE Error
Error-value=1: unsupported class-type.
Error-value=2: invalid class-type.
Error-value=3: class-type and setup priority does not
form a configured TE class.
Sivabalan Expires May 3, 2009 [Page 6]
Internet-Draft draft-ietf-pce-dste-02.txt November 2008
4. Security Considerations
This document does not introduce new security issues. The security
considerations pertaining to PCEP [PCEP-ID] remain relevant.
5. IANA Considerations
IANA maintains a registry of parameters for PCEP. This contains a
sub-registry for PCEP objects. IANA is requested to make new
allocation from this registry as follows:
Object-Class Name Reference
22 CLASSTYPE draft-ietf-pce-dste-02.txt
Object-Type
1: Class Type draft-ietf-pce-dste-02.txt
IANA is requested to make new allocation for error types and values
as follows:
Error-Type Meaning Reference
12 Diff-Serv aware TE error draft-ietf-pce-dste-02.txt
Error-value = 1: draft-ietf-pce-dste-02.txt
Unsupported class-type
Error-value = 2: draft-ietf-pce-dste-02.txt
Invalid class-type
Error-value = 3: draft-ietf-pce-dste-02.txt
Class type and setup priority
does not form a configured TE class
6. Acknowledgments
The authors would like to thank Jean Philippe Vasseur, Adrian
Farrel and Zafar Ali for their valuable comments.
References
Sivabalan Expires May 3, 2009 [Page 7]
Internet-Draft draft-ietf-pce-dste-02.txt November 2008
6.1. Normative References
[RFC4124] Le Faucheur, F. and W. Lai, "Protocol Extensions for
Support of Diffserv-aware MPLS Traffic Engineering", RFC
4124, June 2005.
[PCEP-ID] Path Computation Element (PCE) communication Protocol
(PCEP)", draft-ietf-pce-pcep-18.txt (work in progress),
November 2008.
6.2. Informative References
[RFC4657] Ash, J. and J. Le Roux, "Path Computation Element (PCE)
Communication Protocol Generic Requirements", RFC 4657,
September 2006.
[RFC3564] Le Faucheur, F. and W. Lai, "Requirements for Support of
Differentiated Services-aware MPLS Traffic Engineering",
RFC 3564, July 2003.
[OBJ-ORD] Farrel, A., "Reduced Backus-Naur Form (RBNF) A Syntax Used
in Various Protocol Specifications", draft-farrel-rtg-
common-bnf-07.txt, November 2008.
Author's Addresses
Siva Sivabalan
Cisco Systems, Inc.
2000 Innovation Drive
Kanata, Ontario, K2K 3E8
Canada
Email: msiva@cisco.com
Jon Parker
Cisco Systems, Inc.
2000 Innovation Drive
Kanata, Ontario, K2K 3E8
Canada
Email: jdparker@cisco.com
Sivabalan Expires May 3, 2009 [Page 8]
Internet-Draft draft-ietf-pce-dste-02.txt November 2008
Sami Boutros
Cisco Systems, Inc.
3750 Cisco Way
San Jose, California 95134
USA
Email: sboutros@cisco.com
Kenji Kumaki
KDDI Corporation
Garden Air Tower Iidabashi, Chiyoda-ku
Tokyo, 102-8460
Japan
Email: ke-kumaki@kddi.com
Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
Sivabalan Expires May 3, 2009 [Page 9]
Internet-Draft draft-ietf-pce-dste-02.txt November 2008
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
Acknowledgment
Funding for the RFC Editor function is currently provided by the
Internet Society.
Sivabalan Expires May 3, 2009 [Page 10]