On converged multidomain management of connectivity in heterogeneous networks

We describe an advanced concept and its experimental realisation for open connectivity services to cope with the complexity of multi-technology networks, especially with regard to control, management and algorithmic flexibility across layer-3 routing, layer-2 switching and in future even optical switching. We introduce a unifying control element in each supported network domain called the Domain Control Unit (DCU) that separates the control functions from the data forwarding functions by concentrating most of the control plane mechanisms and intelligence in a single entity. The DCU incorporates PCE-like components for path computation and OpenFlow-like dynamic flow control to enforce the forwarding adjacencies in the switching or routing network. Additionally, the DCU provides intra-domain communication to the packet-forwarding network elements (e.g. routers, switches) in order to collect topological information and to react properly in case of failure. The persistency of the topology and resource information of the network is ensured by a traffic engineering database. The DCU also supports the inter-domain communication between several domain controllers. For experimentation purposes we followed an OpenFlow-like approach to realize a flexible and extensible test installation of the DCU networking concept. This enabled us to demonstrate intra- and inter-domain path computation and flow establishment in a mixed environment of cooperating (layer2) switches and (layer3) routers in virtual and physical networks, as it is common in the context of interconnectivity of large distributed data centers and cloud centers.