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Versions: (draft-vasseur-ccamp-te-node-cap)
00 01 02 03 04 05 RFC 5073
INTERNET-DRAFT J.P. Vasseur (Editor)
Network Working Group Cisco Systems, Inc.
Intended Status: Proposed Standard J.L. Le Roux (Editor)
France Telecom
Expires: October 2007
April 2007
IGP Routing Protocol Extensions for Discovery of Traffic Engineering
Node Capabilities
draft-ietf-ccamp-te-node-cap-05.txt
Status of this Memo
By submitting this Internet-Draft, each author represents that any
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Abstract
It is highly desired in several cases, to take into account Traffic
Engineering (TE) node capabilities during Multi Protocol Label
Switching (MPLS) and Generalized MPLS (GMPLS) Traffic Engineered
Label Switched Path (TE-LSP) selection, such as for instance the
capability to act as a branch Label Switching Router (LSR) of a
Point-To-MultiPoint (P2MP) LSP. This requires advertising these
capabilities within the Interior Gateway Protocol (IGP). For that
purpose, this document specifies Open Shortest Path First (OSPF) and
Intermediate System-Intermediate System (IS-IS) traffic engineering
extensions for the advertisement of control plane and data plane
traffic engineering node capabilities.
Vasseur, Le Roux, et al. [Page 1]
Internet Draft draft-ietf-ccamp-te-node-cap-05.txt April 2007
Table of Contents
1. Terminology.................................................3
2. Introduction................................................3
3. TE Node Capability Descriptor...............................4
3.1. Description.................................................4
3.2. Required Information........................................4
4. TE Node Capability Descriptor TLV formats...................5
4.1. OSPF TE Node Capability Descriptor TLV format...............5
4.2. IS-IS TE Node Capability Descriptor sub-TLV format..........6
5. Elements of procedure.......................................7
5.1. OSPF........................................................7
5.2. IS-IS.......................................................8
6. Backward compatibility......................................8
7. Security Considerations.....................................9
8. IANA considerations.........................................9
8.1. OSPF TLV....................................................9
8.2. ISIS sub-TLV................................................9
8.3. Capability Registry.........................................9
9. Acknowledgments............................................10
10. References.................................................10
10.1. Normative references.......................................10
10.2. Informative References.....................................11
11. Editors' Addresses.........................................11
12. Contributors' Addresses....................................11
13. Intellectual Property Statement............................12
Vasseur, Le Roux, et al. [Page 2]
Internet Draft draft-ietf-ccamp-te-node-cap-05.txt April 2007
1. Terminology
This document uses terminologies defined in [RFC3031], [RFC3209] and
[RFC4461].
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].
2. Introduction
Multi Protocol Label Switching-Traffic Engineering (MPLS-TE) routing
([RFC3784], [RFC3630], [OSPFv3-TE]) relies on extensions to link
state Interior Gateway Protocols (IGP) ([IS-IS], [RFC1195],
[RFC2328], [RFC2740]) in order to advertise Traffic Engineering (TE)
link information used for constraint based routing. Further
Generalized MPLS (GMPLS) related routing extensions are defined in
[RFC4205] and [RFC4203].
It is desired to complement these routing extensions in order to
advertise TE node capabilities, in addition to TE link information.
These TE node capabilities will be taken into account as constraints
during path selection.
Indeed, it is useful to advertise data plane TE node capabilities,
such as the capability for a Label Switching Router (LSR) to be a
branch LSR or a bud-LSR of a Point-To-MultiPoint (P2MP) Label
Switched Path (LSP). These capabilities can then be taken into
account as constraints when computing the route of TE LSPs.
It is also useful to advertise control plane TE node capabilities
such as the capability to support GMPLS signaling for a packet LSR,
or the capability to support P2MP (Point to Multipoint) TE LSP
signaling. This allows selecting a path that avoids nodes that do
not support a given control plane feature, or triggering a mechanism
to support such nodes on a path. Hence this facilitates backward
compatibility.
For that purpose, this document specifies IGP (OSPF and IS-IS)
extensions in order to advertise data plane and control plane
capabilities of a node.
A new TLV is defined for OSPF, the TE Node Capability Descriptor TLV,
to be carried within the Router Information LSA ([OSPF-CAP]).
A new sub-TLV is defined for IS-IS, the TE Node Capability Descriptor
sub-TLV, to be carried within the IS-IS Capability TLV ([IS-IS-CAP]).
Vasseur, Le Roux, et al. [Page 3]
Internet Draft draft-ietf-ccamp-te-node-cap-05.txt April 2007
3. TE Node Capability Descriptor
3.1. Description
LSRs in a network may have distinct control plane and data plane
Traffic Engineering capabilities. The TE Node Capability Descriptor
information defined in this document describes data and control plane
capabilities of an LSR. Such information can be used during path
computation so as to avoid nodes that do not support a given TE
feature either in the control or data plane, or to trigger procedures
to handle these nodes along the path (e.g, trigger LSP hierarchy to
support a legacy transit LSR on a P2MP LSP (see [RSVP-P2MP])).
3.2. Required Information
The TE Node Capability Descriptor contains a variable length set of
bit flags, where each bit corresponds to a given TE node capability.
Five TE Node Capabilities are defined in this document:
- B bit: when set, this flag indicates that the LSR can act
as a branch node on a P2MP LSP (see [RFC4461]);
- E bit: when set, this flag indicates that the LSR can act
as a bud LSR on a P2MP LSP, i.e. an LSR that is both
transit and egress (see [RFC4461]).
- M bit: when set, this flag indicates that the LSR supports
MPLS-TE signaling ([RFC3209]);
- G bit: when set this flag indicates that the LSR supports
GMPLS signaling ([RFC3473]);
- P bit: when set, this flag indicates that the LSR supports
P2MP MPLS-TE signaling ([RSVP-P2MP]).
Note that new capability bits may be added in the future if required.
Vasseur, Le Roux, et al. [Page 4]
Internet Draft draft-ietf-ccamp-te-node-cap-05.txt April 2007
4. TE Node Capability Descriptor TLV formats
4.1. OSPF TE Node Capability Descriptor TLV format
The OSPF TE Node Capability Descriptor TLV is a variable length TLV
that contains a series of bit flags, where each bit correspond to a
TE node capability.
The OSPF TE Node Capability Descriptor TLV is carried within an OSPF
Router Information LSA which is defined in [OSPF-CAP].
The format of the OSPF TE Node Capability Descriptor TLV is the same
as the TLV format used by the Traffic Engineering Extensions to OSPF
[RFC3630]. That is, the TLV is composed of 2 octets for the type, 2
octets specifying the length of the value field and a value field.
The OSPF TE Node Capability Descriptor TLV has the following format:
TYPE: Assigned by IANA - see Section 8.1.
LENGTH: Variable (multiple of 4).
VALUE: Array of units of 32 flags numbered from the most
significant bit as bit zero, where each bit represents
a TE node capability.
The following bits are defined:
Bit Capabilities
0 B bit: P2MP Branch Node capability: When set this indicates
that the LSR can act as a branch node on a P2MP LSP
[RFC4461].
1 E bit: P2MP Bud-LSR capability: When set, this indicates
that the LSR can act as a bud LSR on a P2MP LSP, i.e. an
LSR that is both transit and egress [RFC4461].
2 M bit: If set this indicates that the LSR supports MPLS-TE
signaling ([RFC3209]).
3 G bit: If set this indicates that the LSR supports GMPLS
signaling ([RFC3473]).
4 P bit: If set this indicates that the LSR supports P2MP
MPLS-TE signaling ([RSVP-P2MP]).
5-31 Reserved for future assignments by IANA.
Vasseur, Le Roux, et al. [Page 5]
Internet Draft draft-ietf-ccamp-te-node-cap-05.txt April 2007
4.2. IS-IS TE Node Capability Descriptor sub-TLV format
The IS-IS TE Node Capability Descriptor sub-TLV is a variable length
sub-TLV that contains a series of bit flags, where each bit
correspond to a TE node capability.
The IS-IS TE Node Capability Descriptor sub-TLV is carried within an
IS-IS CAPABILITY TLV which is defined in [IS-IS-CAP].
The format of the IS-IS TE Node Capability sub-TLV is the same as the
TLV format used by the Traffic Engineering Extensions to IS-IS
[RFC3784]. That is, the TLV is composed of 1 octet for the type, 1
octet specifying the TLV length and a value field.
The IS-IS TE Node Capability Descriptor sub-TLV has the following
format:
TYPE: Assigned by IANA - see Section 8.2.
LENGTH: Variable
VALUE: Array of units of 8 flags numbered from the most
significant bit as bit zero, where each bit represents
a TE node capability.
The following bits are defined:
Bit Capabilities
0 B bit: P2MP Branch Node capability: When set this indicates
that the LSR can act as a branch node on a P2MP LSP
[RFC4461].
1 E bit: P2MP Bud-LSR capability: When set, this indicates
that the LSR can act as a bud LSR on a P2MP LSP, i.e. an
LSR that is both transit and egress [RFC4461].
2 M bit: If set this indicates that the LSR supports MPLS-TE
signaling ([RFC3209]).
3 G bit: If set this indicates that the LSR supports GMPLS
signaling ([RFC3473]).
4 P bit: If set this indicates that the LSR supports P2MP
MPLS-TE signaling ([RSVP-P2MP]).
5-7 Reserved for future assignments by IANA.
Vasseur, Le Roux, et al. [Page 6]
Internet Draft draft-ietf-ccamp-te-node-cap-05.txt April 2007
5. Elements of procedure
5.1. OSPF
The TE Node Capability Descriptor TLV is advertised, within an OSPFv2
Router Information LSA (Opaque type of 4 and Opaque ID of 0)
or an OSPFv3 Router Information LSA (function code of 12) which are
defined in [OSPF-CAP]. As such, elements of procedure are inherited
from those defined in [RFC2328], [RFC2740], and [OSPF-CAP].
The TE Node Capability Descriptor TLV advertises capabilities that
may be taken into account as constraints during path selection. Hence
its flooding scope is area-local, and it MUST be carried within
OSPFv2 type 10 Router Information LSA (as defined in [RFC2370]) or an
OSPFv3 Router Information LSA with the S1 bit set and the S2 bit
cleared (as defined in [RFC2740]).
A router MUST originate a new OSPF router information LSA whenever
the content of the TE Node Capability Descriptor TLV changes or
whenever required by the regular OSPF procedure (LSA refresh (every
LSRefreshTime)).
The TE Node Capability Descriptor TLV is OPTIONAL and MUST NOT appear
more than once in an OSPF Router Information LSA. If a TE Node
Capability Descriptor TLV appears more than once in an OSPF Router
Information LSA, only the first occurrence MUST be processed and
other MUST be ignored.
When an OSPF LSA does not contain any TE Node capability Descriptor
TLV, this means that the TE Capabilities of that LSR are unknown.
Note that a change in any of these capabilities MAY trigger CSPF
computation, but MUST NOT trigger normal SPF computation.
Note also that TE node capabilities are expected to be fairly static.
They may change as the result of configuration change, or software
upgrade. This is expected not to appear more than once a day.
Vasseur, Le Roux, et al. [Page 7]
Internet Draft draft-ietf-ccamp-te-node-cap-05.txt April 2007
5.2. IS-IS
The TE Node Capability sub-TLV is carried within an IS-IS CAPABILITY
TLV defined in [IS-IS-CAP]. As such, elements of procedure are
inherited from those defined in [IS-IS-CAP].
The TE Node Capability Descriptor sub-TLV advertises capabilities
that may be taken into account as constraints during path selection.
Hence its flooding is area-local, and MUST be carried within an IS-IS
CAPABILITY TLV having the S flag cleared.
An IS-IS router MUST originate a new IS-IS LSP whenever the content
of any of the TE Node Capability sub-TLV changes or whenever required
by the regular IS-IS procedure (LSP refresh).
The TE Node Capability Descriptor sub-TLV is OPTIONAL and MUST NOT
appear more than once in an ISIS Router Capability TLV.
When an IS-IS LSP does not contain any TE Node capability Descriptor
sub-TLV, this means that the TE Capabilities of that LSR are unknown.
Note that a change in any of these capabilities MAY trigger CSPF
computation, but MUST NOT trigger normal SPF computation.
Note also that TE node capabilities are expected to be fairly static.
They may change as the result of configuration change, or software
upgrade. This is expected not to appear more than once a day.
6. Backward Compatibility
The TE Node Capability Descriptor TLVs defined in this document do
not introduce any interoperability issue. For OSPF, a router not
supporting the TE Node Capability Descriptor TLV will just silently
ignore the TLV as specified in [OSPF-CAP]. For IS-IS a router not
supporting the TE Node Capability Descriptor sub-TLV will just
silently ignore the sub-TLV as specified in [IS-IS-CAP].
When the TE Node capability Descriptor TLV is absent, this means that
the TE Capabilities of that LSR are unknown.
The absence of a word of capability flags in OSPF or an octet of
capability flags in IS-IS means that these capabilities are unknown.
Vasseur, Le Roux, et al. [Page 8]
Internet Draft draft-ietf-ccamp-te-node-cap-05.txt April 2007
7. Security Considerations
This document specifies the content of the TE Node Capability
Descriptor TLV in ISIS and OSPF, to be used for (G)MPLS-TE path
computation. As this TLV is not used for SPF computation or normal
routing, the extensions specified here have no direct effect on IP
routing. Tampering with this TLV may have an effect on Traffic
Engineering computation. Mechanisms defined to secure ISIS Link State
PDUs [RFC3567], OSPF LSAs [RFC2154], and their TLVs, can be used to
secure this TLV as well.
8. IANA considerations
8.1. OSPF TLV
[OSPF-CAP] defines a new code point registry for TLVs carried in the
Router Information LSA defined in [OSPF-CAP].
IANA is requested to make a new codepoint assignment from that
registry for the TE Node Capability Descriptor TLV defined in this
document and carried within the Router Information LSA. The value 1
is suggested. See Section 4.1 of this document.
8.2. ISIS sub-TLV
[IS-IS-CAP] defines a new code point registry for sub-TLVs carried in
the ISIS CAPABILITY TLV defined in [IS-IS-CAP].
IANA is requested to make a new codepoint assignment from that
registry for the TE Node Capability Descriptor sub-TLV defined in
this document, and carried within the ISIS CAPABILITY TLV. The value
1 is suggested. See Section 4.2 of this document.
8.3. Capability Registry
IANA is requested to create a new registry to manage the space of
capability bit flags carried within the OSPF and ISIS TE Node
Capability Descriptor.
A single registry must be defined for both protocols. It is suggested
that a new base registry be created to cover IGP-TE registries that
apply to both OSPF and ISIS, and that the new registry requested by
this document should be a sub-registry of this new bas registry.
Bits in the new regstry should be numbered in the usual IETF notation
starting with the most significant bit as bit zero.
New bit numbers may be allocated only by an IETF Consensus action.
Vasseur, Le Roux, et al. [Page 9]
Internet Draft draft-ietf-ccamp-te-node-cap-05.txt April 2007
Each bit should be tracked with the following qualities:
- Bit number
- Defining RFC
- Name of bit
IANA is requested to make assignments for the five TE node
capabilities defined in this document (see Sections 8.1 and 8.2)
using the following suggested values:
Bit No. Name Reference
--------+---------------------------------------+-----------
1 B bit: P2MP Branch LSR capability [This.I-D]
2 E bit: P2MP Bud LSR capability [This.I-D]
3 M bit: MPLS-TE support [This.I-D]
4 G bit: GMPLS support [This.I-D]
5 P bit: P2MP RSVP-TE support [This.I-D]
9. Acknowledgments
We would like to thank Benoit Fondeviole, Adrian Farrel, Dimitri
Papadimitriou, Acee Lindem and David Ward for their useful comments
and suggestions.
We would also like to thank authors of [RFC4420] and [OSPF-CAP] by
which some text of this document has been inspired.
Adrian Farrel prpeared the final version of this document for
submission to the IESG.
10. References
10.1. Normative references
[RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
dual environments", RFC 1195, December 1990.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2328] Moy, J., "OSPF Version 2", RFC 2328, April 1998.
[RFC2370] Coltun, R., "The OSPF Opaque LSA Option", RFC 2370,
July 1998.
[RFC2740] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6",
RFC 2740, December 1999.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, January 2001.
Vasseur, Le Roux, et al. [Page 10]
Internet Draft draft-ietf-ccamp-te-node-cap-05.txt April 2007
[RFC3209] Awduche, D., et. al., "RSVP-TE: Extensions to RSVP for LSP
tunnels", RFC 3209, December 2001.
[RFC3473] Berger, L, et. al., "GMPLS Signaling RSVP-TE extensions",
RFC 3473, January 2003.
[RFC3630] Katz, D., Yeung, D., Kompella, K., "Traffic Engineering
Extensions to OSPF Version 2", RFC 3630, September 2003.
[RFC3784] Li, T., Smit, H., "IS-IS extensions for Traffic
Engineering", RFC 3784, June 2004.
[IS-IS] "Intermediate System to Intermediate System Intra-Domain
Routeing Exchange Protocol for use in Conjunction with the
Protocol for Providing the Connectionless-mode Network
Service (ISO 8473)", ISO 10589.
[IS-IS-CAP] Vasseur, J.P. et al., "IS-IS extensions for advertising
router information", draft-ietf-isis-caps, work in
progress.
[OSPF-CAP] Lindem, A., Shen, N., Aggarwal, R., Shaffer, S., Vasseur,
J.P., "Extensions to OSPF for advertising Optional Router
Capabilities", draft-ietf-ospf-cap, work in progress.
[RSVP-P2MP] Aggarwal, Papadimitriou, Yasukawa, et. al. "Extensions to
RSVP-TE for point-to-multipoint TE LSPs", draft-ietf-mpls-
rsvp-te-p2mp, work in progress.
10.2. Informative References
[RFC2154] Murphy, S., Badger, M., and B. Wellington, "OSPF with
Digital Signatures", RFC 2154, June 1997.
[RFC3567] Li, T. and R. Atkinson, "Intermediate System to
Intermediate System (IS-IS) Cryptographic Authentication",
RFC 3567, July 2003.
[RFC4203] Kompella, K., Rekhter, Y., "OSPF extensions in support of
Generalized Multi-protocol Label Switching", RFC4203,
October 2005.
[RFC4205] Kompella, K., Rekhter, Y., "IS-IS extensions in support of
Generalized Multi-protocol Label Switching", RFC4205,
October 2005.
[RFC4420] Farrel, A., and al., "Encoding of attributes for MPLS LSPs
establishment Using RSVP-TE", RFC4420, February 2006.
Vasseur, Le Roux, et al. [Page 11]
Internet Draft draft-ietf-ccamp-te-node-cap-05.txt April 2007
[RFC4461] Yasukawa, S., et. al., "Signaling Requirements for Point to
Multipoint Traffic Engineered MPLS LSPs", RFC4461, April
2006.
[OSPFv3-TE] Ishiguro K., Manral V., Davey A., and Lindem A. "Traffic
Engineering Extensions to OSPF version 3", draft-ietf-ospf-
ospfv3-traffic, work in progress.
11. Editors' Addresses
Jean-Philippe Vasseur
Cisco Systems, Inc.
1414 Massachusetts Avenue
Boxborough , MA - 01719
USA
Email: jpv@cisco.com
Jean-Louis Le Roux
France Telecom
2, avenue Pierre-Marzin
22307 Lannion Cedex
FRANCE
Email: jeanlouis.leroux@orange-ftgroup.com
12. Contributors' Addresses
Seisho Yasukawa
NTT
3-9-11 Midori-cho,
Musashino-shi, Tokyo 180-8585, Japan
Email: s.yasukawa@hco.ntt.co.jp
Stefano Previdi
Cisco Systems, Inc
Via Del Serafico 200
Roma, 00142
Italy
Email: sprevidi@cisco.com
Peter Psenak
Cisco Systems, Inc
Pegasus Park DE Kleetlaan 6A
Diegmen, 1831
BELGIUM
Email: ppsenak@cisco.com
Paul Mabbey
Comcast
USA
Vasseur, Le Roux, et al. [Page 12]
Internet Draft draft-ietf-ccamp-te-node-cap-05.txt April 2007
13. Intellectual Property Statement
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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
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WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY
WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE
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FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The IETF Trust (2007). 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.
Vasseur, Le Roux, et al. [Page 13]
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