On providing survivable QoS services in the next generation Internet

We present a comparative study of two schemes to provide survivability for guaranteed QoS connections in a possible next generation Internet network architecture. In the first scheme a QoS connection is provided by standby backup resources on a disjoint path by reserving resources on both the working and backup path. In order to reduce the amount of backup resources required a method for sharing backup resources when the working connections with disjoint routes has been included. In the second scheme a dynamic search for restoration resources is conducted over a preplanned set of alternate paths upon notification of a failure. A simulation based performance study shows that the first scheme results in much higher connection blocking under normal operations, slightly faster restoration times, and longer transient congestion times after fault recovery due to non-optimal backup routing.