Path Computation Clients (PCC) - Path Computation Element (PCE) Requirements for Point-to-Multipoint MPLS-TE
Internet Engineering Task Force (IETF) S. Yasukawa
Request for Comments: 5862 NTT Corporation
Category: Informational A. Farrel
ISSN: 2070-1721 Old Dog Consulting
Path Computation Clients (PCC) - Path Computation Element (PCE)
Requirements for Point-to-Multipoint MPLS-TE
The Path Computation Element (PCE) provides path computation
functions in support of traffic engineering in Multiprotocol Label
Switching (MPLS) and Generalized MPLS (GMPLS) networks.
Extensions to the MPLS and GMPLS signaling and routing protocols have
been made in support of point-to-multipoint (P2MP) Traffic Engineered
(TE) Label Switched Paths (LSPs). The use of PCE in MPLS networks is
already established, and since P2MP TE LSP routes are sometimes
complex to compute, it is likely that PCE will be used for P2MP LSPs.
Generic requirements for a communication protocol between Path
Computation Clients (PCCs) and PCEs are presented in RFC 4657, "Path
Computation Element (PCE) Communication Protocol Generic
Requirements". This document complements the generic requirements
and presents a detailed set of PCC-PCE communication protocol
requirements for point-to-multipoint MPLS/GMPLS traffic engineering.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
Yasukawa & Farrel Informational [Page 1]
RFC 5862 PCC-PCE and P2MP MPLS-TE June 2010
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The Path Computation Element (PCE) defined in [RFC4655] is an entity
that is capable of computing a network path or route based on a
network graph, and applying computational constraints. The intention
is that the PCE is used to compute the path of Traffic Engineered
Label Switched Paths (TE LSPs) within Multiprotocol Label Switching
(MPLS) and Generalized MPLS (GMPLS) networks.
Requirements for point-to-multipoint (P2MP) MPLS TE LSPs are
documented in [RFC4461], and signaling protocol extensions for
setting up P2MP MPLS TE LSPs are defined in [RFC4875]. P2MP MPLS TE
networks are considered in support of various features, including
layer 3 multicast virtual private networks [RFC4834].
Path computation for P2MP TE LSPs presents a significant challenge,
and network optimization of multiple P2MP TE LSPs requires
considerable computational resources. PCE offers a way to offload
such path computations from Label Switching Routers (LSRs).
The applicability of the PCE-based path computation architecture to
P2MP MPLS TE is described in a companion document [RFC5671]. No
further attempt is made to justify the use of PCE for P2MP MPLS TE
within this document.
This document presents a set of PCC-PCE communication protocol
(PCECP) requirements for P2MP MPLS traffic engineering. It
supplements the generic requirements documented in [RFC4657].
Yasukawa & Farrel Informational [Page 2]
RFC 5862 PCC-PCE and P2MP MPLS-TE June 2010
2. Conventions Used in This Document
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].
Although this document is not a protocol specification, this
convention is adopted for clarity of description of requirements.
3. PCC-PCE Communication Requirements for P2MP MPLS Traffic Engineering
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