draft-ietf-pce-pcep-xro-05.txt   draft-ietf-pce-pcep-xro-06.txt 
Network Working Group E. Oki Network Working Group E. Oki
Internet Draft T. Takeda Internet Draft T. Takeda
Intended Status: Standards Track NTT Intended Status: Standards Track NTT
Created: March 24th, 2008 A. Farrel Created: July 18th, 2008 A. Farrel
Expires: September 24th, 2008 Old Dog Consulting Expires: January 18th, 2009 Old Dog Consulting
Extensions to the Path Computation Element Communication Protocol Extensions to the Path Computation Element Communication Protocol
(PCEP) for Route Exclusions (PCEP) for Route Exclusions
draft-ietf-pce-pcep-xro-05.txt draft-ietf-pce-pcep-xro-06.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware 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 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. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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4.1. PCEP Objects .............................................. 12 4.1. PCEP Objects .............................................. 12
4.2. New Subobject for the Include Route Object ................ 13 4.2. New Subobject for the Include Route Object ................ 13
4.3. Error Object Field Values ................................. 13 4.3. Error Object Field Values ................................. 13
4.4. Exclude Route Flags ....................................... 13 4.4. Exclude Route Flags ....................................... 13
5. Manageability Considerations ................................ 14 5. Manageability Considerations ................................ 14
6. Security Considerations ..................................... 14 6. Security Considerations ..................................... 14
7. References .................................................. 14 7. References .................................................. 14
7.1. Normative Reference ....................................... 14 7.1. Normative Reference ....................................... 14
7.2. Informative Reference ..................................... 15 7.2. Informative Reference ..................................... 15
8. Acknowledgements ............................................ 15 8. Acknowledgements ............................................ 15
9. Authors' Addresses .......................................... 15 9. Authors' Addresses .......................................... 16
10. Intellectual Property Statement ............................ 16 10. Intellectual Property Statement ............................ 16
1. Introduction 1. Introduction
The Path Computation Element (PCE) defined in [RFC4655] is an entity The Path Computation Element (PCE) defined in [RFC4655] is an entity
that is capable of computing a network path or route based on a that is capable of computing a network path or route based on a
network graph, and applying computational constraints. A Path network graph, and applying computational constraints. A Path
Computation Client (PCC) may make requests to a PCE for paths to be Computation Client (PCC) may make requests to a PCE for paths to be
computed. computed.
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[RFC3477]. [RFC3477].
Autonomous System Number Subobject Autonomous System Number Subobject
0 1 2 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|X| Type = 4 | Length | 2-Octet AS Number | |X| Type = 4 | Length | 2-Octet AS Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Note that as in other PCEP objects [PCEP] and RSVP-TE objects
[RFC3209], no support for 4-octet AS Numbers is provided. It is
anticipated that, as 4-octet AS Numbers become more common, both
PCEP and RSVP-TE will be updated in a consistent way to add this
support.
SRLG Subobject SRLG Subobject
0 1 2 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|X| Type = 5 | Length | SRLG Id (4 bytes) | |X| Type = 5 | Length | SRLG Id (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRLG Id (continued) | Reserved | Attribute | | SRLG Id (continued) | Reserved | Attribute |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Object (ERO) in the PCRep Message. Object (ERO) in the PCRep Message.
Therefore, during inter-domain diverse path computation, it may be Therefore, during inter-domain diverse path computation, it may be
necessary to request diversity from a path that is not fully known necessary to request diversity from a path that is not fully known
and where a segment of the path is represented by a PKS. This means and where a segment of the path is represented by a PKS. This means
that a PKS may be present as a subobject of the XRO on a PCReq that a PKS may be present as a subobject of the XRO on a PCReq
message. message.
The format and definition of PKS when it appears as an XRO subobject The format and definition of PKS when it appears as an XRO subobject
are as defined in [PCE-PATH-KEY], except for the definition of L bit. are as defined in [PCE-PATH-KEY], except for the definition of L bit.
The L bit of the PKS subobject in the XRO is defined as follows. The L bit of the PKS subobject in the XRO MUST be ignored.
L
The L bit MUST be ignored.
3.1.2. Processing Rules 3.1.2. Processing Rules
Consider that BRPC is applied for both working and backup path Consider that BRPC is applied for both working and backup path
computation in a sequential manner. First, PCC requests PCE for the computation in a sequential manner. First, PCC requests PCE for the
computation of a working path. After BRPC processing has completed, computation of a working path. After BRPC processing has completed,
the PCC receives the results of the working-path computation the PCC receives the results of the working-path computation
expressed in an ERO in a PCRep message. The ERO may include PKSs if expressed in an ERO in a PCRep message. The ERO may include PKSs if
certain segments of the path are to be kept confidential. certain segments of the path are to be kept confidential.
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The field contains 16 bits numbered from 1 as the least significant The field contains 16 bits numbered from 1 as the least significant
bit. bit.
Bit Name Description Reference Bit Name Description Reference
15 F-bit Fail [This.I-D] 15 F-bit Fail [This.I-D]
5. Manageability Considerations 5. Manageability Considerations
A MIB module for management of the PCEP is specified in a separate A MIB module for management of the PCEP is being specified in a
document. This MIB module allows examination of individual PCEP separate document [PCEP-MIB]. That MIB module allows examination of
messages, in particular requests, responses and errors. individual PCEP messages, in particular requests, responses and
errors.
The MIB module MUST be extended to include the ability to view the The MIB module MUST be extended to include the ability to view the
route exclusion extensions defined in this document. route exclusion extensions defined in this document.
Several local policy decisions should be made at the PCE. Firstly, Several local policy decisions should be made at the PCE. Firstly,
the exact behavior with regard to desired exclusions must be the exact behavior with regard to desired exclusions must be
available for examination by an operator and may be configurable. available for examination by an operator and may be configurable.
Second, the behavior on receipt of an unrecognized XRO or EXRS Second, the behavior on receipt of an unrecognized XRO or EXRS
subobject with the X-bit set should be configurable and must be subobject with the X-bit set should be configurable and must be
available for inspection. The inspection and control of these local available for inspection. The inspection and control of these local
policy choices may be part of the PCEP MIB module. policy choices may be part of the PCEP MIB module.
6. Security Considerations 6. Security Considerations
The new exclude route mechanisms defined in this document allow The new exclude route mechanisms defined in this document allow
finer and more specific control of the path computed by a PCE. Such finer and more specific control of the path computed by a PCE. Such
control increases the risk if a PCEP message is intercepted, control increases the risk if a PCEP message is intercepted,
modified, or spoofed. Therefore, the security techniques described modified, or spoofed because it allows the attacker to exert control
over the path that the PCE will compute or to amke the path
computation impossible. Therefore, the security techniques described
in [PCEP] are considered more important. in [PCEP] are considered more important.
Note, however, that the roue exclusion mechanisms also provide the Note, however, that the roue exclusion mechanisms also provide the
operator with the ability to route around vulnerable parts of the operator with the ability to route around vulnerable parts of the
network and may be used to increase overall network security. network and may be used to increase overall network security.
7. References 7. References
7.1. Normative Reference 7.1. Normative Reference
[RFC2119] Bradner, S., "Key words for use in RFCs to indicate [RFC2119] Bradner, S., "Key words for use in RFCs to indicate
requirements levels", RFC 2119, March 1997. requirements levels", RFC 2119, March 1997.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001. Tunnels", RFC 3209, December 2001.
[RFC5152] JP. Vasseur et al, "A Per-domain path computation method
for establishing Inter-domain Traffic Engineering (TE)
Label Switched Paths (LSPs)", RFC 5152, February 2008.
[PCEP] JP. Vasseur et al, "Path Computation Element (PCE) [PCEP] JP. Vasseur et al, "Path Computation Element (PCE)
communication Protocol (PCEP) - Version 1 -", Communication Protocol (PCEP) - Version 1 -",
draft-ietf-pce-pcep (work in progress). draft-ietf-pce-pcep, work in progress.
[PCE-PATH-KEY] R. Bradford, JP Vasseur, and A. Farrel, "Preserving [PCE-PATH-KEY] R. Bradford, JP Vasseur, and A. Farrel, "Preserving
Topology Confidentiality in Inter-Domain Path Computation Topology Confidentiality in Inter-Domain Path Computation
using a key based mechanism", draft-ietf-pce-path-key using a key based mechanism", draft-ietf-pce-path-key,
(work in progress). work in progress.
[BRPC] JP. Vasseur et al, "A Backward Recursive PCE-based [BRPC] JP. Vasseur et al, "A Backward Recursive PCE-based
Computation (BRPC) procedure to compute shortest Computation (BRPC) procedure to compute shortest
inter-domain Traffic Engineering Label Switched Paths", inter-domain Traffic Engineering Label Switched Paths",
draft-ietf-pce-brpc (work in progress). draft-ietf-pce-brpc, work in progress.
[RFC5152] JP. Vasseur et al, "A Per-domain path computation method
for establishing Inter-domain Traffic Engineering (TE)
Label Switched Paths (LSPs)", RFC 5152, February 2008.
7.2. Informative Reference 7.2. Informative Reference
[RFC3477] K. Kompella and Y. Rekhter, "Signalling Unnumbered Links [RFC3477] K. Kompella and Y. Rekhter, "Signalling Unnumbered Links
in Resource ReSerVation Protocol - Traffic Engineering in Resource ReSerVation Protocol - Traffic Engineering
(RSVP-TE)", RFC 3477, January 2003. (RSVP-TE)", RFC 3477, January 2003.
[RFC3812] Srinivasan, C., Viswanathan, A., and T. Nadeau, [RFC3812] Srinivasan, C., Viswanathan, A., and T. Nadeau,
"Multiprotocol Label Switching (MPLS) Traffic Engineering "Multiprotocol Label Switching (MPLS) Traffic Engineering
(TE) Management Information Base (MIB)", RFC 3812, June (TE) Management Information Base (MIB)", RFC 3812, June
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[RFC4657] J. Ash and J.L. Le Roux, "Path Computation Element (PCE) [RFC4657] J. Ash and J.L. Le Roux, "Path Computation Element (PCE)
Communication Protocol Generic Requirements", RFC 4657, Communication Protocol Generic Requirements", RFC 4657,
September 2006. September 2006.
[RFC4874] Lee et al, "Exclude Routes - Extension to Resource [RFC4874] Lee et al, "Exclude Routes - Extension to Resource
ReserVation Protocol-Traffic Engineering (RSVP-TE)", ReserVation Protocol-Traffic Engineering (RSVP-TE)",
RFC 4874, April 2007. RFC 4874, April 2007.
[INTER-DOMAIN-REC-ANA] T. Takeda et al., "Analysis of Inter-domain [INTER-DOMAIN-REC-ANA] T. Takeda et al., "Analysis of Inter-domain
Label Switched Path (LSP) Recovery", Label Switched Path (LSP) Recovery",
draft-ietf-ccamp-inter-domain-recovery-analysis (work in draft-ietf-ccamp-inter-domain-recovery-analysis, work in
progress). progress.
[PCEP-MIB] Koushik, A. S. K., and Stephan, E., "PCE Communication
Protocol(PCEP) Management Information Base", draft-
kkoushik-pce-pcep-mib, work in progress.
8. Acknowledgements 8. Acknowledgements
Authors would like to thank Fabien Verhaeghe for valuable comments Authors would like to thank Fabien Verhaeghe for valuable comments
on subobject formats. on subobject formats. Thanks to Magnus Westerlund, Dan Romascanu,
Tim Polk, and Dave Ward for comments during IESG review.
9. Authors' Addresses 9. Authors' Addresses
Eiji Oki Eiji Oki
NTT NTT
3-9-11 Midori-cho, 3-9-11 Midori-cho,
Musashino-shi, Tokyo 180-8585, Japan Musashino-shi, Tokyo 180-8585, Japan
Email: oki.eiji@lab.ntt.co.jp Email: oki.eiji@lab.ntt.co.jp
Tomonori Takeda Tomonori Takeda
NTT NTT
3-9-11 Midori-cho, 3-9-11 Midori-cho,
Musashino-shi, Tokyo 180-8585, Japan Musashino-shi, Tokyo 180-8585, Japan
Email: takeda.tomonori@lab.ntt.co.jp Email: takeda.tomonori@lab.ntt.co.jp
Adrian Farrel Adrian Farrel
Old Dog Consulting Old Dog Consulting
Email: adrian@olddog.co.uk Email: adrian@olddog.co.uk
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