Applying Routing Policy Differentiation for Diverse QoS Degrees in Multi-domain Optical Networks

IP/MPLS based ASON/GMPLS networks enable the interaction between the IP layer and the optical WDM layer, furthermore it decouples the physical topology from the dynamically created IP topology, which is called Virtual Topology. In this network architecture, there are two known routing policies, they are the Physical Topology First (PTF) and Virtual Topology First (VTF). PTF and VTF are different in the order of actions taken to accommodate a new connection request. PTF will first try to set up a new lightpath in the optical plane while VTF will first try to groom the traffic imposed by the new connection on the virtual plane. The combination of both routing policy provides the opportunity for multilayer traffic engineering (MTE). Additionally the incorporation of both routing policies offers the opportunity to walk around the issue of Quality of Service (QoS) in both IP and WDM optical layers. The challenge is both routing policies PTF/VTF have been applied in the single domain networks scenario, while the application of both routing policies in the optical multilayer multi-domain networks scenario has not been deeply investigated. In this paper we try to combine these routing policies VTF/PTF with the traffic priority level to support a degree of QoS differentiation in an incorporated routing scheme, accordingly we use PTF routing policy to accommodate High Priority (HP) traffic and VTF to accommodate the Low Priority (LP) traffic. The Internet consists of more than 29.000 domains, therefore applying a routing methodology, which supports both routing policies VTF and PTF in a multi-domain scenario is required. Therefore we applied a two level hierarchical routing scheme, this scheme adapts Full Mesh (FM) topology abstraction algorithm in order to support routing in optical multi-domain networks.