In this paper, we present the first open-source path computation element (PCE) emulator along with its key design and implementation features. The PCE is a network control and management entity that can be utilized to perform optimal path computations with multiple constraints in carrier-grade transport networks. The presented architecture incorporates all elements of the standardized PCE framework and is scalable in the number of requests and size of topologies served as well as path computation algorithm complexity. Given the diversity in current control and management practices of carrier-grade transport networks, we also identify key features that are necessary for innovation within the PCE framework, including flexible topology description and update mechanisms, extensible protocol and state machine definitions, and fully programmable path computation. We incorporate all these features in our design and implementation. This work bridges an important gap between network engineering, software system design, and algorithmic studies and shows that deploying a PCE system as such is not only feasible but also well performing in a range of network scenarios from IP/multiprotocol label switching to wavelength-division multiplexing networks.
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