Implementation and Assessment of Pre-reservation Mechanism for PCE Environments
Path computation element (PCE) architecture has been defined for different scenarios such as multi-layer and multi-domain. PCE computes the routes based on the information in the traffic engineering database (TED). TED is updated with the control plane information. However, resource status in the network elements may differ from the information in the TED, because there is a delay from the network element reserves a resource, until the TED is updated. Therefore, PCE can reply with resources, which are busy leading to extra blocking. Pre-reservation mechanism eliminates this blocking, because PCE can book the computed path resources for a certain period as if they were busy. This work demonstrates the importance of this mechanism in two scenarios: multiple PCEs architecture and massive restoration. To do so, we have implemented and tested on a real control plane set-up three schemes to operate with multiple PCEs in a single domain and a massive restoration scenario.
pre-reservation mechanism path computation element path computation massive restoration stolen-lambda block multiple pces scenario time reserved