draft-ietf-mpls-number-0-bw-te-lsps-08.txt   draft-ietf-mpls-number-0-bw-te-lsps-09.txt 
Networking Working Group JP. Vasseur, Ed. Networking Working Group JP. Vasseur, Ed.
Internet-Draft Cisco Systems, Inc Internet-Draft Cisco Systems, Inc
Intended status: Standards Track Matthew. R. Meyer Intended status: Standards Track Matthew. R. Meyer
Expires: June 5, 2008 Global Crossing Expires: August 9, 2008 Global Crossing
K. Kumaki K. Kumaki
KDDI Corporation KDDI Corporation
Alberto. Tempia Bonda Alberto. Tempia Bonda
Telecom Italia Telecom Italia
December 3, 2007 February 6, 2008
A Link-Type sub-TLV to convey the number of Traffic Engineering Label A Link-Type sub-TLV to convey the number of Traffic Engineering Label
Switched Paths signalled with zero reserved bandwidth across a link Switched Paths signalled with zero reserved bandwidth across a link
draft-ietf-mpls-number-0-bw-te-lsps-08 draft-ietf-mpls-number-0-bw-te-lsps-09
Status of this Memo Status of this Memo
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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
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
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The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
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This Internet-Draft will expire on June 5, 2008. This Internet-Draft will expire on August 9, 2008.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2008).
Abstract Abstract
Several Link-type sub-TLVs have been defined for OSPF and IS-IS in Several Link-type sub-TLVs have been defined for OSPF and IS-IS in
the context of Multiprotocol Label Switching (MPLS) Traffic the context of Multiprotocol Label Switching (MPLS) Traffic
Engineering (TE) in order to advertise some link characteristics such Engineering (TE) in order to advertise some link characteristics such
as the available bandwidth, traffic engineering metric, as the available bandwidth, traffic engineering metric,
administrative group and so on. By making statistical assumption administrative group and so on. By making statistical assumption
about the aggregated traffic carried onto a set of TE Label Switched about the aggregated traffic carried onto a set of TE Label Switched
Paths (LSPs) signalled with zero bandwith (referred to as Paths (LSPs) signalled with zero bandwith (referred to as
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Unconstrained TE LSP: A TE LSP signalled with a bandwidth equal to 0 Unconstrained TE LSP: A TE LSP signalled with a bandwidth equal to 0
2. Introduction 2. 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 Router) 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 (since the TE LSP computed by the path computation
algorithm (e.g. CSPF) will be no different than the IGP (Interior algorithm (e.g. CSPF) will be no different than the IGP (Interior
Gateway Protocol) shortest path should the TE metric be equal to the Gateway Protocol) shortest path should the TE metric be equal to the
IGP metric) but is protected with MPLS TE Fast Reroute. IGP metric) but is protected with MPLS TE Fast Reroute.
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
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symmetrical networks when unconstrained TE LSPs are used, such symmetrical networks when unconstrained TE LSPs are used, such
metrics (e.g. path cost, number of hops, ...) are usually ineffective metrics (e.g. path cost, number of hops, ...) are usually ineffective
and may lead to poorly load balanced traffic. and may lead to poorly load balanced traffic.
By making statistical assumption about the aggregated traffic carried By making statistical assumption about the aggregated traffic carried
by a set of TE LSPs signalled with no bandwidth requirement (referred by a set of TE LSPs signalled with no bandwidth requirement (referred
to as unconstrained TE LSPs in this document), algorithms can be to as unconstrained TE LSPs in this document), algorithms can be
designed to load balance (existing or newly configured) unconstrained designed to load balance (existing or newly configured) unconstrained
TE Label Switched Path (LSP) across a set of equal cost paths. This TE Label Switched Path (LSP) across a set of equal cost paths. This
requires knowledge of the number of unconstrained Traffic Engineering requires knowledge of the number of unconstrained Traffic Engineering
Label Switched Path(s) (TE LSP) signalled across each link. 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 outside
the scope of this document and is referred to for the sake of the scope of this document and is referred to for the sake of
illustration of the motivation for gathering such information. 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 TE LSPs in case of a link example to evaluate the number of affected unconstrained TE LSPs in
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 [RFC3784]) in the context of MPLS Traffic Engineering [RFC3630] and [RFC3784]) in the context of MPLS Traffic Engineering
in order to advertise various link characteristics such as the in order to advertise various link characteristics such as the
available bandwidth, traffic engineering metric, administrative group available bandwidth, traffic engineering metric, administrative group
and so on. As currently defined in [RFC3630] and [RFC3784] the and so on. As currently defined in [RFC3630] and [RFC3784] the
information related to the number of unconstrained TE LSP(s) is not information related to the number of unconstrained TE LSP(s) is not
available. This document specifies a new Link-type Traffic available. This document specifies a new Link-type Traffic
Engineering sub-TLV used to indicate the number of unconstrained TE Engineering sub-TLV used to indicate the number 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 not be included in the count that is reported. management system MAY be omitted from the count that is reported.
3. Protocol extensions 3. Protocol extensions
The Number of 0-bandwidth TE LSP(s) Sub-TLV is defined that specifies The Unconstrained TE LSPs count sub-TLV is defined that specifies the
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 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 [RFC3784]. 22) specified in [RFC3784]. If a second instance of the
Unconstrained TE LSP Count sub-TLV is present, the receiving 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): To be assigned by IANA (suggested value = 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 LSP(s) 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 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 the Traffic Engineering LSA specified in [RFC3630] or
the OSPFv3 Intra-Area-TE LSA (function code 10) defined in the OSPFv3 Intra-Area-TE LSA (function code 10) defined in
[I-D.ietf-ospf-ospfv3-traffic]. If a second instance of the Number [I-D.ietf-ospf-ospfv3-traffic]. If a second instance of the
of 0-bandwidth TE LSP(s) sub-TLV is present, the receiving system Unconstrained TE LSP Count sub-TLV is present, the receiving system
MUST only process the first instance of the sub-TLV. MUST only process the first 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): To be assigned by IANA (suggested value = 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 LSP(s) signalled across
the link. the link.
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Suggested Value TLV Name Reference Suggested Value TLV Name Reference
23 Unconstrained TE LSP Count (sub-)TLV This document 23 Unconstrained TE LSP Count (sub-)TLV This document
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 the IS-IS protocols. Security
considerations are covered in [RFC2328] and [RFC2470] for the base considerations are covered in [RFC2328] and [RFC2470] for the base
OSPF protocol and in [RFC1194] for IS-IS. OSPF protocol and in [RFC1195] for IS-IS.
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 and Loa Anderson Daniel King, Acee Lindem, Lou Berger, Attila Takacs and Loa Anderson
for their useful inputs. for their useful inputs.
8. References 8. References
8.1. Normative References 8.1. Normative References
[I-D.ietf-ospf-ospfv3-traffic] [I-D.ietf-ospf-ospfv3-traffic]
Ishiguro, K., "Traffic Engineering Extensions to OSPF Ishiguro, K., "Traffic Engineering Extensions to OSPF
version 3", draft-ietf-ospf-ospfv3-traffic-09 (work in version 3", draft-ietf-ospf-ospfv3-traffic-09 (work in
progress), September 2007. progress), September 2007.
[RFC1194] Zimmerman, D., "Finger User Information Protocol", [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
RFC 1194, November 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.
[RFC2470] Crawford, M., Narten, T., and S. Thomas, "Transmission of [RFC2470] Crawford, M., Narten, T., and S. Thomas, "Transmission of
IPv6 Packets over Token Ring Networks", RFC 2470, IPv6 Packets over Token Ring Networks", RFC 2470,
December 1998. December 1998.
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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 (2007). 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
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
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