Evaluation of architectures for reliable server pooling in wired and wireless environments

Reliable server pooling (RSP) allows a pool of redundant information sources to be viewed as a single transport endpoint and, therefore, it is able to provide persistent connections and balanced traffic for different applications. The Internet Engineering Task Force RSerPool Working Group has proposed an architecture to implement the RSP; it defines an overlay network providing an upper layer protocol or an application with a range of reliability services, from simple server selection to a fully automatic session-failover capability. The simulation experiments conducted in both wired and wireless environments show that the current version of the RSerPool works well in fixed and relatively reliable environments, but its performance worsens rapidly as the networks become more unreliable or mobile. The issues we have identified in wireless mobile ad hoc networks include network partition, high signaling overhead, difficulty in synchronization among name servers, and excessive aggressiveness in handling failures. Alternative design options for the RSP in wireless and mobile environments are introduced and evaluated.