draft-ietf-mpls-number-0-bw-te-lsps-12.txt   rfc5330.txt 
Networking Working Group JP. Vasseur, Ed. Network Working Group JP. Vasseur, Ed.
Internet-Draft Cisco Systems, Inc Request for Comments: 5330 Cisco Systems, Inc
Intended status: Standards Track Matthew. R. Meyer Category: Standards Track M. Meyer
Expires: March 5, 2009 Global Crossing BT
K. Kumaki K. Kumaki
KDDI Corporation KDDI R&D Labs
Alberto. Tempia Bonda A. Bonda
Telecom Italia Telecom Italia
September 1, 2008 October 2008
A Link-Type sub-TLV to convey the number of Traffic Engineering Label
Switched Paths signalled with zero reserved bandwidth across a link
draft-ietf-mpls-number-0-bw-te-lsps-12
Status of this Memo
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The list of current Internet-Drafts can be accessed at A Link-Type sub-TLV to Convey the Number of
http://www.ietf.org/ietf/1id-abstracts.txt. Traffic Engineering Label Switched Paths Signalled with
Zero Reserved Bandwidth across a Link
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This Internet-Draft will expire on March 5, 2009. This document specifies an Internet standards track protocol for the
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Abstract Abstract
Several Link-type sub-Type-Lenght-Values (sub-TLVs) have been defined Several Link-type sub-Type-Length-Values (sub-TLVs) have been defined
for Open Shortest Path First (OSPF) and Intermediate System to for Open Shortest Path First (OSPF) and Intermediate System to
Intermediate System (IS-IS) in the context of Multiprotocol Label Intermediate System (IS-IS) in the context of Multiprotocol Label
Switching (MPLS) Traffic Engineering (TE) in order to advertise some Switching (MPLS) Traffic Engineering (TE), in order to advertise some
link characteristics such as the available bandwidth, traffic link characteristics such as the available bandwidth, traffic
engineering metric, administrative group and so on. By making engineering metric, administrative group, and so on. By making
statistical assumptions about the aggregated traffic carried onto a statistical assumptions about the aggregated traffic carried onto a
set of TE Label Switched Paths (LSPs) signalled with zero bandwith set of TE Label Switched Paths (LSPs) signalled with zero bandwidth
(referred to as unconstrained TE LSP in this document), and with the (referred to as "unconstrained TE LSP" in this document), algorithms
can be designed to load balance (existing or newly configured)
unconstrained TE LSP across a set of equal cost paths. This requires
knowledge of the number of unconstrained TE LSPs signalled across a knowledge of the number of unconstrained TE LSPs signalled across a
link, algorithms can be designed to load balance (existing or newly link. This document specifies a new Link-type Traffic Engineering
configured) unconstrained TE LSP across a set of equal cost paths. sub-TLV used to advertise the number of unconstrained TE LSPs
This requires knowledge of the number of unconstrained TE LSPs signalled across a link.
signalled across a link. This document specifies a new Link-type
Traffic Engineering sub-TLV used to advertise the number of
unconstrained TE LSP(s) signalled across a link.
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].
Table of Contents Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction ....................................................2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology .....................................................3
3. Protocol extensions . . . . . . . . . . . . . . . . . . . . . 5 2.1. Requirements Language ......................................4
3.1. IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Protocol Extensions .............................................4
3.2. OSPF . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.1. IS-IS ......................................................4
4. Elements of procedure . . . . . . . . . . . . . . . . . . . . 6 3.2. OSPF .......................................................4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 4. Elements of Procedure ...........................................5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7 5. IANA Considerations .............................................5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 6. Security Considerations .........................................5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7. Acknowledgements ................................................6
8.1. Normative References . . . . . . . . . . . . . . . . . . . 7 8. References ......................................................6
8.2. Informative References . . . . . . . . . . . . . . . . . . 8 8.1. Normative References .......................................6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 8.2. Informative References .....................................6
Intellectual Property and Copyright Statements . . . . . . . . . . 10
1. Terminology
Terminology used in this document
CSPF: Constrained Shortest Path First
IGP : Interior Gateway Protocol
LSA: Link State Advertisement
LSP: Link State Packet
MPLS: Multiprotocol Label Switching
LSR: Label Switching Router
SRLG: Shared Risk Link Group
TE LSP: Traffic Engineering Label Switched Path
Unconstrained TE LSP: A TE LSP signalled with a bandwidth equal to 0
2. Introduction 1. Introduction
It is not uncommon to deploy MPLS Traffic Engineering for the sake of It is not uncommon to deploy MPLS Traffic Engineering for the sake of
fast recovery relying on a local protection recovery mechanism such fast recovery, relying on a local protection recovery mechanism such
as MPLS TE Fast Reroute (see [RFC4090]). In this case, a deployment as MPLS TE Fast Reroute (see [RFC4090]). In this case, a deployment
model consists of deploying a full mesh of TE LSPs signalled with model consists of deploying a full mesh of TE LSPs signalled with
zero bandwidth (also referred to as unconstrained TE LSP in this zero bandwidth (also referred to as unconstrained TE LSP in this
document) between a set of LSRs (Label Switching Routers) and document) between a set of LSRs (Label Switching Routers) and
protecting these TE LSPs against link, SRLG (Shared Risk Link Group) protecting these TE LSPs against link, SRLG (Shared Risk Link Group),
and/or node failures with pre-established backup tunnels. The and/or node failures with pre-established backup tunnels. The
traffic routed onto such unconstrained TE LSPs simply follows the IGP traffic routed onto such unconstrained TE LSPs simply follows the IGP
shortest path (since the TE LSP computed by the path computation shortest path, but is protected with MPLS TE Fast Reroute. This is
algorithm (e.g. CSPF) will be no different than the IGP (Interior because the TE LSP computed by the path computation algorithm (e.g.,
Gateway Protocol) shortest path should the TE metric be equal to the CSPF) will be no different than the IGP (Interior Gateway Protocol)
IGP metric) but is protected with MPLS TE Fast Reroute. shortest path should the TE metric be equal to the IGP metric.
When a reoptimization process is triggered for an existing TE LSP, When a reoptimization process is triggered for an existing TE LSP,
the decision on whether to reroute that TE LSP onto a different path the decision on whether to reroute that TE LSP onto a different path
is governed by the discovery of a lower cost path satisfying the is governed by the discovery of a lower cost path satisfying the
constraints (other metrics such that the percentage of reserved constraints (other metrics, such as the percentage of reserved
bandwidth or the number of hops can also be used). Unfortunately, bandwidth or the number of hops, can also be used). Unfortunately,
metrics such as the path cost or the number of hops may be metrics such as the path cost or the number of hops may be
ineffective in various circumstances: for example, in the case of a ineffective in various circumstances. For example, in the case of a
symmetrical network with ECMPs (Equal Cost Multi-Paths), if the symmetrical network with ECMPs (Equal Cost Multi-Paths), if the
network operator uses unconstrained TE LSP, this may lead to a poorly network operator uses unconstrained TE LSP, this may lead to a poorly
load balanced traffic: indeed, several paths between a source and a load balanced traffic; indeed, several paths between a source and a
destination of a TE LSP may exist that have the same cost and the destination of a TE LSP may exist that have the same cost, and the
reservable amount of bandwidth along each path cannot be used as a reservable amount of bandwidth along each path cannot be used as a
tie-breaker. tie-breaker.
By making statistical assumptions about the aggregated traffic By making statistical assumptions about the aggregated traffic
carried by a set of TE LSPs signalled with no bandwidth requirement carried by a set of unconstrained TE LSPs, algorithms can be designed
(referred to as unconstrained TE LSPs in this document), algorithms to load balance (existing or newly configured) unconstrained TE LSPs
can be designed to load balance (existing or newly configured) across a set of equal cost paths. This requires knowledge of the
unconstrained TE Label Switched Paths (LSPs) across a set of equal number of unconstrained TE LSPs signalled across each link.
cost paths. This requires knowledge of the number of unconstrained
Traffic Engineering Label Switched Paths (TE LSPs) signalled across
each link.
Note that the specification of load balancing algorithms is outside Note that the specification of load balancing algorithms is
the scope of this document and is referred to for the sake of outside the scope of this document and is referred to for the sake
illustration of the motivation for gathering such information. of illustration of the motivation for gathering such information.
Furthermore, the knowledge of the number of unconstrained TE LSPs Furthermore, the knowledge of the number of unconstrained TE LSPs
signalled across each link can be used for other purposes, for signalled across each link can be used for other purposes -- for
example to evaluate the number of affected unconstrained TE LSPs in example, to evaluate the number of affected unconstrained TE LSPs in
case of a link failure. case of a link failure.
A set of Link-type sub-TLVs have been defined for OSPF and IS-IS (see A set of Link-type sub-TLVs have been defined for OSPF and IS-IS (see
[RFC3630] and [I-D.ietf-isis-te-bis]) in the context of MPLS Traffic [RFC3630] and [RFC5305]) in the context of MPLS Traffic Engineering
Engineering in order to advertise various link characteristics such in order to advertise various link characteristics such as the
as the available bandwidth, traffic engineering metric, available bandwidth, traffic engineering metric, administrative
administrative group and so on. As currently defined in [RFC3630] group, and so on. As currently defined in [RFC3630] and [RFC5305],
and [I-D.ietf-isis-te-bis] the information related to the number of the information related to the number of unconstrained TE LSPs is not
unconstrained TE LSP(s) is not available. This document specifies a available. This document specifies a new Link-type Traffic
new Link-type Traffic Engineering sub-TLV used to indicate the number Engineering sub-TLV used to indicate the number of unconstrained TE
of unconstrained TE LSPs signalled across a link. LSPs signalled across a link.
Unconstrained TE LSPs that are configured and provisioned through a Unconstrained TE LSPs that are configured and provisioned through a
management system MAY be omitted from the count that is reported. management system MAY be omitted from the count that is reported.
3. Protocol extensions 2. Terminology
Two Unconstrained TE LSP count sub-TLVs are defined that specify the Terminology used in this document:
CSPF: Constrained Shortest Path First
IGP : Interior Gateway Protocol
LSA: Link State Advertisement
LSP: Link State Packet
MPLS: Multiprotocol Label Switching
LSR: Label Switching Router
SRLG: Shared Risk Link Group
TE LSP: Traffic Engineering Label Switched Path
Unconstrained TE LSP: A TE LSP signalled with a bandwidth equal to 0
2.1. 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].
3. Protocol Extensions
Two Unconstrained TE LSP Count sub-TLVs are defined that specify the
number of TE LSPs signalled with zero bandwidth across a link. number of TE LSPs signalled with zero bandwidth across a link.
3.1. IS-IS 3.1. IS-IS
The IS-IS Unconstrained TE LSP Count Sub-TLV is OPTIONAL and MUST NOT The IS-IS Unconstrained TE LSP Count sub-TLV is OPTIONAL and MUST NOT
appear more than once within the extended IS reachability TLV (type appear more than once within the extended IS reachability TLV (type
22) specified in [I-D.ietf-isis-te-bis] or the MT Intermediate 22) specified in [RFC5305] or the Multi-Topology (MT) Intermediate
Systems TLV (type 222) specified in [RFC5120]. If a second instance Systems TLV (type 222) specified in [RFC5120]. If a second instance
of the Unconstrained TE LSP Count sub-TLV is present, the receiving of the Unconstrained TE LSP Count sub-TLV is present, the receiving
system MUST only process the first instance of the sub-TLV. system MUST only process the first instance of the sub-TLV.
The IS-IS Unconstrained TE LSP Count Sub-TLV format is defined below: The IS-IS Unconstrained TE LSP Count sub-TLV format is defined below:
Type (1 octet): To be assigned by IANA (suggested value = 23) Type (1 octet): 23
Length (1 octet): 2 Length (1 octet): 2
Value (2 octets): number of unconstrained TE LSP(s) signalled across Value (2 octets): number of unconstrained TE LSPs signalled across
the link. the link.
3.2. OSPF 3.2. OSPF
The OSPF Unconstrained TE LSP Count TLV is OPTIONAL and MUST NOT The OSPF Unconstrained TE LSP Count sub-TLV is OPTIONAL and MUST NOT
appear more than once within the Link TLV (Type 2) that is itself appear more than once within the Link TLV (Type 2) that is itself
carried within the Traffic Engineering LSA specified in [RFC3630] or carried within either the Traffic Engineering LSA specified in
the OSPFv3 Intra-Area-TE LSA (function code 10) defined in [RFC3630] or the OSPFv3 Intra-Area-TE LSA (function code 10) defined
[I-D.ietf-ospf-ospfv3-traffic]. If a second instance of the in [RFC5329]. If a second instance of the Unconstrained TE LSP Count
Unconstrained TE LSP Count sub-TLV is present, the receiving system sub-TLV is present, the receiving system MUST only process the first
MUST only process the first instance of the sub-TLV. instance of the sub-TLV.
The OSPF Unconstrained TE LSP Count Sub-TLV format is defined below: The OSPF Unconstrained TE LSP Count sub-TLV format is defined below:
Type (2 octets): To be assigned by IANA (suggested value = 23) Type (2 octets): 23
Length (2 octets): 4 Length (2 octets): 4
Value (4 octets): number of unconstrained TE LSP(s) signalled across Value (4 octets): number of unconstrained TE LSPs signalled across
the link. the link.
4. Elements of procedure 4. Elements of Procedure
The absence of the Unconstrained TE LSP Count (sub-)TLV SHOULD be The absence of the Unconstrained TE LSP Count sub-TLV SHOULD be
interpreted as an absence of information about the link. interpreted as an absence of information about the link.
Similarly to other MPLS Traffic Engineering link characteristics, Similar to other MPLS Traffic Engineering link characteristics,
LSA/LSP origination trigger mechanisms are outside the scope of this LSA/LSP origination trigger mechanisms are outside the scope of this
document. Care must be given to not trigger the systematic flooding document. Care must be given to not trigger the systematic flooding
of a new IS-IS LSP or OSPF LSA with a too high granularity in case of of a new IS-IS LSP or OSPF LSA with a too high granularity in case of
change of the number of unconstrained TE LSPs. change in the number of unconstrained TE LSPs.
5. IANA Considerations 5. IANA Considerations
IANA has defined a sub-registry for the sub-TLVs carried in the IS-IS IANA has defined a sub-registry for the sub-TLVs carried in the IS-IS
TLV 22. IANA is requested to assign a new TLV code-point for the TLV 22 and has assigned a new TLV codepoint for the Unconstrained TE
Unconstrained TE LSP Count sub-TLV carried within the TLV 22. LSP Count sub-TLV carried within the TLV 22.
Suggested Value TLV Name Reference Value TLV Name Reference
23 Unconstrained TE LSP Count (sub-)TLV This document 23 Unconstrained TE LSP Count (sub-)TLV RFC 5330
IANA has defined a sub-registry for the sub-TLVs carried in an OSPF IANA has defined a sub-registry for the sub-TLVs carried in an OSPF
TE Link TLV (type 2). IANA is requested to assign a new sub-TLV TE Link TLV (type 2) and has assigned a new sub-TLV codepoint for the
code-point for the Unconstrained TE LSP Count sub-TLV carried within Unconstrained TE LSP Count sub-TLV carried within the TE Link TLV.
the TE Link TLV.
Suggested Value TLV Name Reference Value TLV Name Reference
23 Unconstrained TE LSP Count (sub-)TLV This document 23 Unconstrained TE LSP Count (sub-)TLV RFC 5330
6. Security Considerations 6. Security Considerations
The function described in this document does not create any new The function described in this document does not create any new
security issues for the OSPF and the IS-IS protocols. Security security issues for the OSPF and IS-IS protocols. Security
considerations are covered in [RFC2328] and [RFC5340] for the base considerations are covered in [RFC2328] and [RFC5340] for the base
OSPF protocol and in [RFC1195] and [I-D.ietf-isis-rfc3567bis] for OSPF protocol and in [RFC1195] and [RFC5304] for IS-IS.
IS-IS.
A security framework for MPLS and Generalized MPLS can be found in A security framework for MPLS and Generalized MPLS can be found in
[I-D.ietf-mpls-mpls-and-gmpls-security-framework]. [G/MPLS].
7. Acknowledgements 7. Acknowledgements
The authors would like to thank Jean-Louis Le Roux, Adrian Farrel, The authors would like to thank Jean-Louis Le Roux, Adrian Farrel,
Daniel King, Acee Lindem, Lou Berger, Attila Takacs, Pasi Eronen, Daniel King, Acee Lindem, Lou Berger, Attila Takacs, Pasi Eronen,
Russ Housley, Tim Folk and Loa Anderson for their useful inputs. Russ Housley, Tim Polk, and Loa Anderson for their useful inputs.
8. References 8. References
8.1. Normative References 8.1. Normative References
[I-D.ietf-isis-rfc3567bis]
Li, T. and R. Atkinson, "Intermediate System to
Intermediate System (IS-IS) Cryptographic
Authentication", draft-ietf-isis-rfc3567bis-03 (work in
progress), July 2008.
[I-D.ietf-isis-te-bis]
Li, T. and H. Smit, "IS-IS extensions for Traffic
Engineering", draft-ietf-isis-te-bis-00 (work in
progress), April 2008.
[I-D.ietf-ospf-ospfv3-traffic]
Ishiguro, K., Manral, V., Davey, A., and A. Lindem,
"Traffic Engineering Extensions to OSPF version 3",
draft-ietf-ospf-ospfv3-traffic-13 (work in progress),
June 2008.
[RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
dual environments", RFC 1195, December 1990. dual environments", RFC 1195, December 1990.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998. [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630, (TE) Extensions to OSPF Version 2", RFC 3630, September
September 2003. 2003.
[RFC5304] Li, T. and R. Atkinson, "Intermediate System to
Intermediate System (IS-IS) Cryptographic Authentication",
RFC 5304, October 2008.
[RFC5305] Li, T. and H. Smit, "IS-IS extensions for Traffic
Engineering", RFC 5305, October 2008.
[RFC5329] Ishiguro, K., Manral, V., Davey, A., and A. Lindem, Ed.,
"Traffic Engineering Extensions to OSPF Version 3", RFC
5329, September 2008.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, July 2008. for IPv6", RFC 5340, July 2008.
8.2. Informative References 8.2. Informative References
[I-D.ietf-mpls-mpls-and-gmpls-security-framework] [G/MPLS] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Fang, L. and M. Behringer, "Security Framework for MPLS Networks", Work In Progress, July 2008.
and GMPLS Networks",
draft-ietf-mpls-mpls-and-gmpls-security-framework-03 (work
in progress), July 2008.
[RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute [RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast
Extensions to RSVP-TE for LSP Tunnels", RFC 4090, Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
May 2005. May 2005.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120, February 2008. Intermediate Systems (IS-ISs)", RFC 5120, February 2008.
Authors' Addresses Authors' Addresses
JP Vasseur (editor) JP Vasseur (editor)
Cisco Systems, Inc Cisco Systems, Inc
1414 Massachusetts Avenue 1414 Massachusetts Avenue
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Email: jpv@cisco.com EMail: jpv@cisco.com
Matthew R. Meyer Matthew R. Meyer
Global Crossing BT
3133 Indian Valley Tr. Boston, MA
Howell, MI 48855
USA USA
Email: mrminc@gmail.com EMail: matthew.meyer@bt.com
Kenji Kumaki Kenji Kumaki
KDDI Corporation KDDI R&D Laboratories, Inc.
Garden Air Tower Iidabashi, Chiyoda-ku, 2-1-15 Ohara Fujimino
Tokyo, 102-8460 Saitama 356-8502, JAPAN
JAPAN
Email: ke-kumaki@kddi.com EMail: ke-kumaki@kddi.com
Alberto Tempia Bonda Alberto Tempia Bonda
Telecom Italia Telecom Italia
via G. Reiss Romoli 274 via G. Reiss Romoli 274
Torino, 10148 Torino, 10148
ITALIA ITALIA
Email: alberto.tempiabonda@telecomitalia.it EMail: alberto.tempiabonda@telecomitalia.it
Full Copyright Statement Full Copyright Statement
Copyright (C) The IETF Trust (2008). Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. 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 an
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