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 policies provides the opportunity for multilayer traffic engineering (MTE). Additionally the incorporation of both routing policies improves the Quality of Service (QoS) in both IP and WDM optical layers. The challenge being that both routing policies have been applied in the single domain network 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 integrated routing scheme. 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 multilayer routing methodology in a multi-domain scenario is required. In this work we apply a two level hierarchical routing scheme, which adapts the Full Mesh (FM) topology abstraction algorithm in order to support multilayer routing in optical multi-domain networks.