Lightpath bundling and anycast switching: a new paradigm for multilayer optical networks

In IP over WDM multilayer optical networks, IP routers are interconnected by all-optical channels called lightpaths, of typical rates of 10, 40, or, more recently, 100 Gb/s. In this context, lightpath bundling (LB) and anycast switching (AS) are control plane and data plane techniques, respectively, both of them to be implemented in the IP routers. LB permits grouping a set of lightpaths between two nodes that follow a common route so that they are perceived by the IP layer as a single virtual link of aggregated capacity. In its turn, AS consists of instructing the router to implement a per-packet-granularity balancing of the traffic among the lightpaths in the bundle, reducing the packet delay and the buffering requirements in the node. This happens transparently to the IP layer, which, because of the LB configuration, sees the bundled lightpaths as a single entity. In this article, we propose the combined application of the LB and AS techniques as a new paradigm (LB+AS) for optical networks. Applying the LB+AS concept requires seamless changes in the electronic equipment and no changes in the optical infrastructure. We present a case study that shows the significant performance and cost benefits LB+AS can bring to the network and its inherent scalability. In addition, we discuss other potential advantages of LB+AS and related open research lines.