Dynamic routing of real-time virtual circuits

Future integrated services networks, such as ATM networks, will support diverse services, including the guaranteed real-time service required by many applications such as voice and video. To support such services, virtual circuit (VC) routing algorithms are often proposed. Typically, the source maintains a view of the network, and uses this view to select a path to the destination. A request is then made to setup a real-time VC over this path through resource reservations. The request is blocked if the requested resources are not available. These VC routing algorithms are usually evaluated individually in terms of steady-state performance measures. In this paper, we compare several VC routing schemes in terms of instantaneous measures using a time-dependent evaluation method. Our results show that a routing scheme which defines the cost of a path as the sum of measured link utilizations yields more stable behavior and lower VC blocking probability over a wide range of workload parameters and network configurations than other traditional schemes