Delay budget partitioning to maximize network resource usage efficiency

Provisioning techniques for network flows with end-to-end QoS guarantees need to address the interpath and intrapath load balancing problems to maximize the resource utilization efficiency. This paper focuses on the intrapath load balancing problem: How to partition the end-to-end QoS requirement of a network flow along the links of a given path such that the deviation in the loads on these links is as small as possible? We propose a new algorithm to solve the end-to-end QoS partitioning problem for unicast and multicast flows that takes into account the loads on the constituent links of the chosen flow path. This algorithm can simultaneously partition multiple end-to-end QoS requirements such as the end-to-end delay and delay violation probability bound. The key concept in our proposal is the notion of slack, which quantifies the extent of flexibility available in partitioning the end-to-end delay requirement across the links of a selected path (or a multicast tree). We show that one can improve network resource usage efficiency by carefully selecting a slack partition that explicitly balances the loads on the underlying links. A detailed simulation study demonstrates that, compared with previous approaches, the proposed delay budget partitioning algorithm can increase the total number of long-term flows that can be provisioned along a network path by up to 1.2 times for deterministic and 2.8 times for statistical delay guarantees