This paper proposes a new networking paradigm introducing the broker-plane above the management planes of Autonomous Systems (ASes). The brokers communicate with the manager of each AS to assist coordinate end-to-end resource management and path provisioning across the multi-AS networks involving multiple operators. The broker plane updates the virtual network topology, manages the resource information of inter-AS links and aggregated (abstracted) intra-AS links, and computes end-to-end routing, modulation formats, and spectrum assignment (RMSA). Notwithstanding, due to the different dynamicity of each AS, the probability of finding a multi-AS transparent path fulfilling the spectrum continuity and contiguity constraints might be low. To improve the grade of the inter-domain connectivity service, spectrum converters can be installed in inter-domain nodes or per-AS defragmentation can be performed with a global view. In this paper, we introduce a mechanism where each AS can advertise its internal capabilities, e.g., spectrum conversion, their ability to implement spectrum defragmentation or any other network feature. The Multi-AS RMSA with Defragmentation Capability problem is presented and mathematically modeled. A heuristic algorithm is designed to solve it. The mechanism's workflow is comprehensively tested using simulations. Results show connection blocking reduction as high as 26%, clearly validating the benefits of the proposed mechanism. Finally, its experimental assessment was conducted on a distributed multi-continental testbed.

Peer Reviewed