One of the important additions of GMPLS is a Link Management Protocol (LMP), to establish, release and manage TE links between two adjacent GMPLS-capable nodes. This protocol is described in RFC 4204 and in User Network Interface (UNI) 1.0 Signaling Specification by OIF.

LMP consists of 5 different functions as follows:

Link correlation (see RFC 4204):
This procedure is used to aggregate data link into TE link and to exchange data link features in order to make some consistency check.
Link verification (see RFC 4204):
This procedure is used to check the data link connectivity and to dynamically discover the TE and data link remote Id.
Fault localization (see RFC 4204):
When a data link fails, all the downstream nodes may detect it and generate an alarm without knowing on which data link the failure actually occurred. The fault localization allows the failed data link upstream node to localize the failure (i.e. To detect that the failure is between that node and the adjacent downstream node).
Service discovery (see OIF UNI):
This procedure allows a UNI-C and UNI-N to exchange information concerning the client service capabilities and the transport network services.
Trace Monitoring:
This procedure allows a node to do trace monitoring by using the SONET/SDH capabilities.


MARBEN GMPLS includes a relevant solution for LMP issue. It consists of:

  • A protocol stack entity implementing LMP,
  • A LMP Development Kit offering a unified access to the routing information gathered by ISIS-TE or OSPF-TE,
  • The TE database is shared with MARBEN Traffic engineering solution.

The C or C++ interface is based on a simple constructor called to instantiate an LMP user application which returns a handle for all the message set of LMP message that must be send over the network.

The development kit includes automatic processing on incoming messages: A programmer can thus use these automatic responses on the incoming LMP messages in order to speed up their integration or skip them and customized every single answer.