A backward-compatible inter-domain multipath routing framework

We present a framework to facilitate the inter-domain multipath routing for carrier networks that are based on circuit switching technologies, without significant changes to the existing inter-domain protocols. We first introduce a simple mechanism, namely, Single Routing Plane Multipath (SRPM) which can be easily implemented in the existing PCE-based inter-domain architectures. The main idea behind the SRPM method is to represent multiple link disjoint paths as a single virtual edge in the PCE and thus use the existing single path routing mechanisms to enable multipath routing. We further present a more generic mechanism, referred to as Multiple Routing Plane Multipath (MRPM) method, with the goal to facilitate the provisioning of multipath connections over dynamically selected domain chains. In this method, we propose to virtualize the network into multiple slices and represent as multiple routing topologies by the PCEs. In this way, multiple routing planes are constructed to facilitate inter-domain routing. For both methods, we consider the buffer size as constraint for multipath routing due to the resulting differential delay. The results show that the proposed methods can significantly improve the blocking performance and are backward compatible, while only slightly impacting the intra-domain traffic.