draft-ietf-isis-link-attr-01.txt   draft-ietf-isis-link-attr-02.txt 
ISIS WG ISIS WG
Internet Draft Jean-Philippe Vasseur Internet Draft Jean-Philippe Vasseur
Stefano Previdi Stefano Previdi
Cisco Systems Cisco Systems
Document: draft-ietf-isis-link-attr-02.txt
Expires: April 2007 October 2006
Proposed Status : Standard
Definition of an IS-IS Link Attribute sub-TLV Definition of an IS-IS Link Attribute sub-TLV
draft-ietf-isis-link-attr-01.txt draft-ietf-isis-link-attr-02.txt
Status of this Memo Status of this Memo
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Abstract Abstract
This document defines a sub-TLV called "Link-attributes" carried This document defines a sub-TLV called "Link-attributes" carried
within the TLV 22 and used to flood some link characteristics. within the TLV 22 and used to flood some link characteristics.
Conventions used in this document Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
document are to be interpreted as described in RFC-2119 [i]. this document are to be interpreted as described in RFC-2119 [RFC].
Table of contents Table of contents
1. Introduction...................................................2 1. Introduction ..................................................2
2. Link-attributes sub-TLV format.................................2 2. Link-attributes sub-TLV format ................................2
3. Interoperability with routers non supporting this capability...3 3. Interoperability with routers non supporting this capability ..3
4. Security considerations........................................3 4. Security considerations .......................................3
5. IANA considerations............................................3 5. IANA considerations ...........................................3
6. Intellectual Property Considerations...........................3 6. Intellectual Property Considerations ..........................3
7. Acknowledgments................................................4 7. Acknowledgments ...............................................4
8. References.....................................................4 8. References ....................................................4
8.1 Normative references.......................................4 8.1 Normative references .........................................4
8.2 Informative references.....................................4 8.2 Informative references .......................................4
9. Authors' Addresses.............................................5 9. Authors' Addresses ............................................4
Full Copyright Statement..........................................5 Full Copyright Statement .........................................5
1. Introduction 1. Introduction
[IS-IS] specifies the IS-IS protocol (ISO 10589) with extensions to [IS-IS] specifies the IS-IS protocol (ISO 10589) with extensions to
support IPv4 in [IS-IS-IP]. A router advertises one or several Link support IPv4 in [IS-IS-IP]. A router advertises one or several Link
State Protocol data units which are composed of variable length State Protocol data units which are composed of variable length
tuples called TLVs (Type-Length-Value). tuples called TLVs (Type-Length-Value).
[IS-IS-TE] defines a set of new TLVs whose aims are to add more [IS-IS-TE] defines a set of new TLVs whose aims are to add more
information about links characteristics, increase the range of IS-IS information about links characteristics, increase the range of IS-IS
metrics and optimize the encoding of IS-IS prefixes. metrics and optimize the encoding of IS-IS prefixes.
This document defines a new sub-TLV named "Link-attributes" carried This document defines a new sub-TLV named "Link-attributes" carried
within the extended IS reachability TLV (type 22) specified in [IS- within the extended IS reachability TLV (type 22) specified in
IS-TE]. [IS-IS-TE].
2. Link-attributes sub-TLV format 2. Link-attributes sub-TLV format
The link-attribute sub-TLV is carried within the TLV 22 and has a The link-attribute sub-TLV is carried within the TLV 22 and has a
format identical to the sub-TLV format used by the Traffic format identical to the sub-TLV format used by the Traffic
Engineering Extensions for IS-IS [IS-IS-TE]: 1 octet of sub-type, 1 Engineering Extensions for IS-IS [IS-IS-TE]: 1 octet of sub-type, 1
octet of length of the value field of the sub-TLV followed by the octet of length of the value field of the sub-TLV followed by the
value field in this case, a 16 bit flags field. value field, in this case, a 16 bit flags field.
The Link-attribute sub-type is 19 (to be assigned by IANA) and has a The Link-attribute sub-type is 19 (to be assigned by IANA) and has a
length of 2 octets. length of 2 octets.
This sub-TLV is OPTIONAL and MAY appear at most once for a single IS This sub-TLV is OPTIONAL and MAY appear at most once for a single IS
neighbor. neighbor. If a received LSP contains more than one Link-Attribute
Sub-TLV, an implementation MAY decide to consider only the first
encountered instance.
The following bits are defined: The following bits are defined:
Local Protection Available (0x01). When set, this indicates that the Local Protection Available (0x01). When set, this indicates that the
link is protected by means of some local protection mechanism (e.g link is protected by means of some local protection mechanism (e.g
[FRR]). [FRR]).
Link excluded from local protection path (0x02). When set, this link Link excluded from local protection path (0x02). When set, this link
SHOULD not be included in any computation of a repair path by any SHOULD not be included in any computation of a repair path by any
other router in the routing area. The triggers for setting up this other router in the routing area. The triggers for setting up this
bit are out of the scope of this document. bit are out of the scope of this document.
Such link characteristics has several applications such as
constrained shortest path computation for a Traffic Engineering Label
Switched (TE LSP) path or the triggering of specific actions in the
context of IS-IS SPF computation.
Local maintenance required (0x04). When set, this indicates that the
link will be put out of service and will consequently be shortly
unavailable. The set of actions triggered by other nodes is out of
the scope of this document. An example of the usage of this bit is
provided in [GR-SHUT].
3. Interoperability with routers non supporting this capability 3. Interoperability with routers non supporting this capability
A router not supporting the link-attribute sub-TLV MUST just silently A router not supporting the link-attribute sub-TLV MUST just
ignore this sub-TLV. silently ignore this sub-TLV.
Where the information in the link attributes sub-TLV is used to
affect the IS-IS SPF calculation, additional information indicating
which routers are using this information is required to insure such
usage does not result in loops or black holes. How this additional
information is conveyed is outside the scope of this document.
4. Security considerations 4. Security considerations
No new security issues are raised in this document. No new security issues are raised in this document.
5. IANA considerations 5. IANA considerations
IANA will assign a new codepoint for the link-attribute sub-TLV IANA will assign a new codepoint for the link-attribute sub-TLV
defined in this document and carried within TLV 22. Suggested value defined in this document and carried within TLV 22. Suggested value
is 19 (to be assigned by IANA). is 19 (to be assigned by IANA).
6. Intellectual Property Considerations 6. Intellectual Property Considerations
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed
pertain to the implementation or use of the technology described in to pertain to the implementation or use of the technology described
this document or the extent to which any license under such rights in this document or the extent to which any license under such
might or might not be available; nor does it represent that it has rights might or might not be available; nor does it represent that
made any independent effort to identify any such rights. Information it has made any independent effort to identify any such rights.
on the procedures with respect to rights in RFC documents can be Information on the procedures with respect to rights in RFC
found in BCP 78 and BCP 79. documents can be found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an 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 attempt made to obtain a general license or permission for the use
such proprietary rights by implementers or users of this of such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository
http://www.ietf.org/ipr. at http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf- this standard. Please address the information to the IETF at
ipr@ietf.org. ietf-ipr@ietf.org.
7. Acknowledgments 7. Acknowledgments
The authors would like to thank Mike Shand and Les Ginsberg for their The authors would like to thank Mike Shand and Les Ginsberg for
useful comments. their useful comments.
8. References 8. References
8.1 Normative references 8.1 Normative references
[RFC] Bradner, S., "Key words for use in RFCs to Indicate Requirement [RFC] Bradner, S., "Key words for use in RFCs to Indicate
Levels," RFC 2119. Requirement Levels," RFC 2119.
[IS-IS] "Intermediate System to Intermediate System Intra-Domain [IS-IS] "Intermediate System to Intermediate System Intra-Domain
Routeing Exchange Protocol for use in Conjunction with the Protocol Routeing Exchange Protocol for use in Conjunction with the Protocol
for Providing the Connectionless-mode Network Service (ISO 8473)", for Providing the Connectionless-mode Network Service (ISO 8473)",
ISO 10589. ISO 10589.
[IS-IS-IP] Callon, R., RFC 1195, "Use of OSI IS-IS for routing in [IS-IS-IP] Callon, R., RFC 1195, "Use of OSI IS-IS for routing in
TCP/IP and dual environments", RFC 1195, December 1990. TCP/IP and dual environments", RFC 1195, December 1990.
[IS-IS-TE] H. Smit, T. Li, "IS-IS extensions for traffic [IS-IS-TE] H. Smit, T. Li, "IS-IS extensions for traffic
engineering", RFC 3784. engineering", RFC 3784.
8.2 Informative references 8.2 Informative references
[FRR] Ping Pan, et al, "Fast Reroute Extensions to RSVP-TE for LSP [FRR] Ping Pan, et al, "Fast Reroute Extensions to RSVP-TE for LSP
Tunnels", draft-ietf-mpls-rsvp-lsp-fastreroute-07.txt. Work in Tunnels", RFC 4090, May 2005.
progress.
[GR-SHUT], Z. Ali et al, "Graceful Shutdown in MPLS Traffic
Engineering Networks", draft-ali-ccamp-mpls-graceful-shutdown-01.txt.
Work in progress.
9. Authors' Addresses 9. Authors' Addresses
Jean-Philippe Vasseur Jean-Philippe Vasseur
CISCO Systems, Inc. Cisco Systems, Inc.
300 Beaver Brook 1414 Massachusetts Avenue
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Email: jpv@cisco.com Email: jpv@cisco.com
Stefano Previdi Stefano Previdi
CISCO Systems, Inc. Cisco Systems, Inc.
Via Del Serafico 200 Via Del Serafico 200
00142 - Roma 00142 - Roma
ITALY ITALY
Email: sprevidi@cisco.com Email: sprevidi@cisco.com
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2005). This document is subject Copyright (C) The Internet Society (2006). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights. except as set forth therein, the authors retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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