PCE

The control of MPLS or GMPLS network demands efficient path computation engine to provide paths that:

  • Fulfil service level agreement (i.e. QOS, protection scheme).
  • Optimise network resource usage in a complex ( multilayer and multi domain) and large network ( multi ISP with partial visibility)

In the MPLS and GMPLS architecture the path computation was typically performed inside network elements. However, this approach has shown some limitations due to:

  • High complexity of specific application such as point to multipoint or inter-layer path computation.
  • Network topology lack of visibility and, confidentiality issue in inter-carrier case.

That is why IETF has a proposed a Path Computation Element (PCE) Based Architecture as defined in RFC 4655.
It defines the use of a new functional equipment called PCE in charge to compute the path on any client request using complex algorithm and Traffic engineering information collected through routing protocols.

PceArchitecture
Composite PCE versus an External PCE

This architecture is mainly formed of 3 types of protocols:

  • The PCE communication protocol (PCEP) which is a TCP client/server application where a client (PCC) can request a path to a path computation server (PCE).
  • A discovery protocol to help PCC to know about existing PCEs.
  • An IGP that enables the PCE to get the traffic engineering database of the whole Networks.

The PCE protocol that has been elected is a new IP protocol acting as a client server protocol with extensions that enable cooperation between PCE to solve inter domain routing. Find below the scheme for such.

PceProtocol
Protocol exchange through 3 different PCEs which cooperate to build the explicit Route

MARBEN PCE

The MARBEN PCE offers a user-friendly flexible API on top of a complete protocol stack to ease and speed up the integration of PCEP feature inside a network element either as a PCC or as a PCE.
It is fully conformant with IETF PCEP standards and also supports extensions such Exclude Route, Objective Function, PathKey protection and Global Concurrent Optimisation.

Marben is closely and actively following IETF PCE working group to maintain its implementation up to date with latest extensions required by its customers.

MARBEN PCE consists of two different modules:

  • PCE entity
    • mainly in charge of the PCEP session maintenance, PCEP message coding/decoding and trace facilities,
  • PCE development Kit;
    • API offering the possibility to the user-application to build/send/Receive PCEP messages (i.e. Path Computation Request/Reply, Error, Notification).
These two PCE modules could be augmented with MARBEN routing offer running ISIS-TE or OSPF-TE as addition. Marben products also provides constrained path computation algorithm that could be customized and used to build a PCE offer.
Pcep
MARBEN PCE-P offer for PCE server
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