Benefits of Connection Request Bundling in a PCE-based WDM Network

The Path Computation Element (PCE) concept is considered to be beneficial in the network connection setup operations, especially in optical networks based on wavelength division multiplex (WDM) transport technology. In the PCE paradigm, communication between a node and the PCE is specified by the Path Computation Element Communication Protocol (PCEP). PCEP allows the PCC (Path Computation Client) to send to the PCE more than one LSP (path computation) request at a time, i.e., multiple LSP requests can be bundled together before being sent to the PCE. Enabling bundling, and consequently the concurrent optimization of a large set of LSP requests at the PCE, may result in significant improvements in terms of network optimization and reduced control plane overhead. However, these advantages come at a cost of increased connection setup-delay. This paper explores pros and cons of enabling bundling of LSP requests in terms of both control plane overhead reduction and benefits of sequential vs. concurrent path computation operations. A variety of scenarios are analyzed, including a WDM mesh network providing LSPs with both dedicated and shared path protection. Results demonstrate significant gains in terms of reduced control overhead using LSP bundling, and reduction in blocking probability using concurrent processing of bundled LSP requests at the PCE. 1