Traffic Engineering in GMPLS
The purpose of the routing function is to advertise and to gather static and dynamic TE data on the network: topology, addressing information, metrics, maximum bandwidth, reservable bandwidth, etc. The routing function allows every node in the network to build a TE database that can be used to compute constrained paths within the network. Dynamic routing protocols such as IS-IS and OSPF have been extended at the IETF in order to flood (for the time being, within a single area) such TE data.
The key feature of an optical control plane is that the topology of the control plane could not be congruent to the topology of the transport plane where optical links are built. Moreover, the TE data related to the transport plane must be handled by the application that controls this transport plane. The routing module of the networking stack cannot therefore process the TE data (at least all those related to transport plane links), and such data must be made available to an external application. This is exactly the purpose of MARBEN Traffic Engineering Development Kit.
MARBEN Traffic Engineering DevKit
MARBEN GMPLS suite includes an autonomous solution for Traffic engineering matter. It consists of:
- A protocol stack entity implementing ISIS-TE and OSPF-TE;
- A Traffic Engineering Development Kit offering a unified access to the routing information gathered by ISIS-TE or OSPF-TE,
- A TE database and the complete and efficient set of lookup queries.
It conforms with the latest OIF, IETF and ITU works and contributions.
The TE development kit handles the graceful restart of the underlying router as defined in RFC 3623.The TE development kit user is notified of the beginning/end of the graceful restart of the router through a callback function. The TE Development Kit can be used to build an application supporting DDRP architecture as defined in [OIF-DDRP].
The C or C++ interface is based on a simple constructor called to instantiate a specific user application as MPLS, OIF UNI, IUT UNI or OIF E-NNI which returns a handle for all the message set of every LSA that must be advertised for instance.
A user-application may want to advertise TE data for a FA, a bundled link or a local link that belongs to the transport plane. Such links are obviously ignored during SPF computation (in GMPLS networks, such links cannot usually carry IP packets) and are only intended for C-SPF computation by TE applications.