MARBEN Routing Controller

The routing controller is defined in ITU-TG.8080 to:

  • respond to requests from connection controllers for path (route) information needed to set up connections. This information can vary from end-to-end (e.g., source routing) to next hop;
  • respond to requests for topology (SNPs and their abstractions) information for network management purposes.

Information contained in the routing controller enables it to provide routes within the domain of its responsibility. This information includes both topology (SNPPs, SNP Link Connections) and SNP addresses (network addresses) that correspond to the end system addresses all at a given layer.

Addressing information about other subnetworks at the same layer (peer subnets) is also maintained. It may also maintain knowledge of SNP state to enable constraint based routing. Using this view, a possible route can be determined between two or more (sets of ) SNPs taking into account some routing constraints. There are varying levels of routing detail that span the following.

MARBEN Routing Controller provides path computation capabilities as listed:

  • A simple Dijkstra shortest-path-first algorithm;
  • A cost-optimized node-diverse path computation algorithm;
  • A number-of-hops-optimized node-diverse path computation algorithm;
  • A cost-optimized link-diverse path computation algorithm;
  • A number-of-hops-optimized link-diverse path computation algorithm.

All these algorithms are constrained by various Traffic Engineering parameters such as the requested setup priority, resource affinities and switching capabilities, excluded or mandated resources, etc... : before invoking one of the path computation algorithm, the MARBEN Routing Controller is in charge of extracting routing information from the Traffic Engineering development kit database, pruning nodes or links according to exclude routes, crank-back information, requested bandwidth, priorities and resource affinities, etc... , and formatting the resulting routing information.

MARBEN Routing Controller can also acts a PCE Client getting its explicit route from a PCE server. The Policy - local computation vs PCE server is selected by the policy enforcement point agent.

Here after 2 different path results for a simple one metric cost network:

Node disjoint, optimal cost but not hop count
Link Diverse Node algorithm