Low Overhead Path Computation Flooding

In (Perelló et al., 2010) a variation on the PCF is proposed, in the Low Overhead Path Computation Flooding (Lo-PCF) architecture a PCE from a given domain would only add the VSPT from one domain for each request Id. In order to accomplish this, upon receipt of a PRep message containing a VSPT the PCE checks if any other Prep from that request Id have already been processed, if so it discards the message. In case no reply message for that request Id have already been processed, the PCE updates the VSPT and forwards it in a message to all upstream domain PCEs. This scheme may lead to suboptimal resulting path compared to the PCF scheme, but it results in much lessen control messages exchanged. For this scheme to work properly request Ids must globally unique in the multi-domain network, but this scheme guarantees loop free path calculation without requiring a domain list as it is necessary in the PCF.

Perelló, J.; Hernández-Sola, G.; Agraz, F.; Spadaro, S. & Comellas, J. (2010), 'Scalable Path Computation Flooding Approach for PCE-Based Multi-domain Networks', ETRI journal 32(4).