The PCE Working Group is chartered to specify the required protocols so
as to enable a Path Computation Element (PCE)-based architecture for the
computation of paths for MPLS and GMPLS Point to Point and Point to
Multi-point Traffic Engineered LSPs.
In this architecture path computation does not necessarily occur on the
head-end (ingress) LSR, but on some other path computation entity that
may physically not be located on each head-end LSR.
The PCE WG works on application of this model within a single domain
or within a group of domains (where a domain is a layer, IGP area or
Autonomous System with limited visibility from the head-end LSR). At
this time, applying this model to large groups of domains such as the
Internet is not thought to be possible, and the PCE WG will not spend
energy on that topic.
The WG specifies the PCE communication Protocol (PCEP) and needed
extensions for communication between LSRs (termed Path Computation
Clients - PCCs) and PCEs, and between cooperating PCEs. Security
mechanisms such as authentication and confidentiality are included.
The WG determines requirements for extensions to existing routing and
signaling protocols in support of the PCE architecture and the signaling
of inter-domain paths (e.g. RSVP-TE and its GMPLS variations). Any
necessary extensions will be produced in collaboration with the Working
Groups responsible for the protocols.
The WG also works on the mechanisms to for multi-layer path computation
and PCEP extensions for communication between several network layers.
The WG defines the required PCEP extensions for Wavelength Switched
Optical Networks (WSON) while keeping consistency with the GMPLS
architecture specified in the CCAMP WG.
- PCEP extensions for MPLS and GMPLS Traffic Engineered LSP path
computation models involving PCE(s). This includes the case of
computing the paths of intra and inter-domain TE LSPs. Such path
computation includes the generation of primary, protection and
recovery paths, as well as computations for (local/global)
reoptimization and load balancing. Both intra- and inter-domain
applications are covered.
- In cooperation with protocol specific Working Group (e.g., MPLS,
CCAMP), development of LSP signaling (RSVP-TE) extensions required
to support PCE-based path computation models.
- Specification of PCEP extensions for communication in the various
GMPLS-controlled networks, including WSON.
- Definition of PCEP extensions for path computation in multi-layer
- Definition of the PCEP extensions used by a stateful PCE for
recommending a new path for an existing or new LSP to the PCC/PCE.
Further protocol extensions must cover the case where the
recommendation is not followed by the PCC/PCE.