draft-ietf-pce-inter-layer-req-07.txt   draft-ietf-pce-inter-layer-req-08.txt 
Network Working Group Eiji Oki (Editor) Network Working Group T. Takeda (Ed.)
Internet Draft NTT Internet Draft NTT
Category: Informational Category: Informational A. Farrel (Ed.)
Expires: October 9th, 2008 April 9th, 2008 Created: October 15, 2008 Old Dog Consulting
Expires: April 15, 2009
PCC-PCE Communication and PCE Discovery Requirements for PCC-PCE Communication and PCE Discovery Requirements for
Inter-Layer Traffic Engineering Inter-Layer Traffic Engineering
draft-ietf-pce-inter-layer-req-07.txt draft-ietf-pce-inter-layer-req-08.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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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. network graph, and applying computational constraints.
A network may comprise multiple layers. These layers may represent A network may comprise multiple layers. These layers may represent
separations of technologies (e.g., packet switch capable (PSC), time separations of technologies (e.g., packet switch capable (PSC), time
division multiplex (TDM), lambda switch capable (LSC)) [RFC3945], division multiplex (TDM), lambda switch capable (LSC)) [RFC3945],
separation of data plane switching granularity levels (e.g., PSC-1 separation of data plane switching granularity levels (e.g., PSC-1
and PSC-2, or VC4 and VC12) [MLN-REQ], or a distinction between and PSC-2, or VC4 and VC12) [RFC5212], or a distinction between
client and server networking roles (e.g., commercial or client and server networking roles (e.g., commercial or
administrative separation of client and server networks). In this administrative separation of client and server networks). In this
multi-layer network, LSP in lower layers are used to carry upper- multi-layer network, LSP in lower layers are used to carry upper-
layer LSPs. The network topology formed by lower-layer LSPs and layer LSPs. The network topology formed by lower-layer LSPs and
advertised to the higher layer is called a Virtual Network Topology advertised to the higher layer is called a Virtual Network Topology
(VNT) [MLN-REQ]. (VNT) [RFC5212].
In layered networks under the operation of MPLS-TE and GMPLS In layered networks under the operation of MPLS-TE and GMPLS
protocols, it is important to provide mechanisms to allow global protocols, it is important to provide mechanisms to allow global
optimization of network resources. That is, to take into account all optimization of network resources. That is, to take into account all
layers, rather than optimizing resource utilization at each layer layers, rather than optimizing resource utilization at each layer
independently. This allows better network efficiency to be achieved. independently. This allows better network efficiency to be achieved.
This is what we call Inter-layer traffic engineering. This includes This is what we call Inter-layer traffic engineering. This includes
mechanisms allowing computation of end-to-end paths across layers mechanisms allowing computation of end-to-end paths across layers
(known as inter-layer path computation), and mechanisms for control (known as inter-layer path computation), and mechanisms for control
and management of the VNT by setting up and releasing LSPs in the and management of the VNT by setting up and releasing LSPs in the
lower layers [MLN-REQ]. lower layers [RFC5212].
Inter-layer traffic engineering is included in the scope of the PCE Inter-layer traffic engineering is included in the scope of the PCE
architecture [RFC4655], and PCE can provide a suitable mechanism for architecture [RFC4655], and PCE can provide a suitable mechanism for
resolving inter-layer path computation issues. The applicability of resolving inter-layer path computation issues. The applicability of
the PCE-based path computation architecture to inter-layer traffic the PCE-based path computation architecture to inter-layer traffic
engineering is described in [PCE-INTER-LAYER-FRWK]. engineering is described in [PCE-INTER-LAYER-FRWK].
This document presents sets of PCC-PCE communication protocol (PCECP) This document presents sets of PCC-PCE communication protocol (PCECP)
and PCE Discovery protocol requirements for inter-layer traffic and PCE Discovery protocol requirements for inter-layer traffic
engineering. It supplements the generic requirements documented in engineering. It supplements the generic requirements documented in
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information distributed by TE extensions to the routing protocol information distributed by TE extensions to the routing protocol
operating within the network. In order that the PCE can select a operating within the network. In order that the PCE can select a
suitable path for the signaling protocol to use to install the inter- suitable path for the signaling protocol to use to install the inter-
layer LSP, the topology graph must include information about the layer LSP, the topology graph must include information about the
inter-layer signaling and forwarding (i.e. adaptation) capabilities inter-layer signaling and forwarding (i.e. adaptation) capabilities
of each LSR in the network. of each LSR in the network.
Whatever means is used to collect the information to build the Whatever means is used to collect the information to build the
topology graph MUST include the requisite information. If the TE topology graph MUST include the requisite information. If the TE
extensions to the routing protocol are used, these SHOULD satisfy the extensions to the routing protocol are used, these SHOULD satisfy the
requirements as described in [MLN-REQ]. requirements as described in [RFC5212].
4.6. Impact on Network Operation 4.6. Impact on Network Operation
The use of a PCE to compute inter-layer paths is not expected to have The use of a PCE to compute inter-layer paths is not expected to have
significant impact on network operations. But it should be noted that significant impact on network operations. But it should be noted that
the introduction of inter-layer support to a PCE that already the introduction of inter-layer support to a PCE that already
provides mono-layer path computation might change the loading of the provides mono-layer path computation might change the loading of the
PCE and that might have an impact on the network behavior especially PCE and that might have an impact on the network behavior especially
during recovery periods immediately after a network failure. during recovery periods immediately after a network failure.
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Element (PCE)-Based Architecture", RFC 4655, September Element (PCE)-Based Architecture", RFC 4655, September
2006. 2006.
[RFC4657] J. Ash, J.L Le Roux et al., " Path Computation Element [RFC4657] J. Ash, J.L Le Roux et al., " Path Computation Element
(PCE) Communication Protocol Generic Requirements", RFC (PCE) Communication Protocol Generic Requirements", RFC
4657, September 2006. 4657, September 2006.
[RFC4674] JL Le Roux et al., "Requirements for Path Computation [RFC4674] JL Le Roux et al., "Requirements for Path Computation
Element (PCE) Discovery", RFC 4674, September 2006. Element (PCE) Discovery", RFC 4674, September 2006.
[MLN-REQ] K. Shiomoto et al., "Requirements for GMPLS-based multi- [RFC5212] K. Shiomoto et al., "Requirements for GMPLS-Based Multi-
region and multi-layer networks (MRN/MLN)", draft-ietf- Region and Multi-Layer Networks (MRN/MLN)", RFC 5212, July
ccamp-gmpls-mln-reqs (work in progress). 2008.
[PCE-INTER-LAYER-FRWK] E. Oki et al., "Framework for PCE-Based [PCE-INTER-LAYER-FRWK] E. Oki et al., "Framework for PCE-Based
Inter-Layer MPLS and GMPLS Traffic Engineering", draft- Inter-Layer MPLS and GMPLS Traffic Engineering", draft-
ietf-pce-inter-layer-frwk (work in progress). ietf-pce-inter-layer-frwk (work in progress).
[PCEP-MIB] A. Koushik, and E. Stephan, "PCE communication protocol [PCEP-MIB] A. Koushik, and E. Stephan, "PCE communication protocol
(PCEP) Management Information Base", draft-kkoushik-pce- (PCEP) Management Information Base", draft-kkoushik-pce-
pcep-mib (work in progress). pcep-mib (work in progress).
[RFC5145] K. Shiomoto, "Framework for MPLS-TE to GMPLS Migration", [RFC5145] K. Shiomoto, "Framework for MPLS-TE to GMPLS Migration",
RFC 5145, March 2008. RFC 5145, March 2008.
[RFC5146] K. Kumaki et al., "Interworking Requirements to Support [RFC5146] K. Kumaki et al., "Interworking Requirements to Support
Operation of MPLS-TE over GMPLS Networks", RFC 5146, March Operation of MPLS-TE over GMPLS Networks", RFC 5146, March
2008. 2008.
9. Authors' Addresses 9. Authors' Addresses
Eiji Oki Eiji Oki
NTT University of Electro-Communications
3-9-11 Midori-cho, Tokyo
Musashino-shi, Tokyo 180-8585, Japan Japan
Email: oki.eiji@lab.ntt.co.jp Email: oki@ice.uec.ac.jp
Jean-Louis Le Roux Jean-Louis Le Roux
France Telecom R&D, France Telecom R&D,
Av Pierre Marzin, Av Pierre Marzin,
22300 Lannion, France 22300 Lannion, France
Email: jeanlouis.leroux@orange-ftgroup.com Email: jeanlouis.leroux@orange-ftgroup.com
Kenji Kumaki Kenji Kumaki
KDDI Corporation KDDI Corporation
Garden Air Tower Garden Air Tower
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