Routing in DS-TE networks with an opportunistic bandwidth allocation model

DS-TE (DiffServ-aware MPLS-TE) networks support Quality of Service (QoS) implementation for traffic classes (TCs). Bandwidth Allocation Models (BAMs) are used in DS-TE networks in order to define Bandwidth Constraints (BCs) in a per-class basis and effectively define how this resource is reserved and eventually shared by applications. Existing BAM models are aware of traffic classes and are enablers for QoS guarantees while trying to optimize the use of bandwidth resources on a per-link basis. This paper proposes a new bandwidth allocation model (AllocTC-Sharing) which has an opportunistic behavior on a per-link basis. Opportunistic behavior means that AllocTC-Sharing allows higher priority traffic classes to use non-allocated resources of lower priority traffic classes and the other way around. The paper presents initially the AllocTC-Sharing and its integration with CSPF (Constrained Shortest Path First) routing protocol for end-to-end MPLS LSP (Label Switched Path) path setup. Then, we compare AllocTC-Sharing features with RDM (Russian Dolls Model) and Adapt-RDM models. The results show that AllocTC-Sharing preserves the features of RDM and Adapt-RDM and improves overall network utilization.