The performance of routing and control protocols on virtual rings

The starting point of this paper is a class of multi-ring network designs, which enjoy the one-bridge property: the path between any two nodes is either confined to a single ring, or traverses exactly two rings (passing through a single bridge node). Such networks can be constructed using combinatorial block designs called generalized quadrangles. We first present novel routing and flow control protocols, which we collectively call VRing, that capitalize on the one-bridge property of the multi-ring network. Our protocols ensure that (i) no loss due to congestion occurs inside a network, under arbitrary traffic patterns; (ii) all the packets reach their destinations within bounded time with low jitter; and (iii) the bandwidth is allocated fairly and no host is starved. We compare the performance of the VRing protocols to that of a generic WAN protocol, with shortest path routing and reliable transport, which we call INet. Our simulation results show that virtual ring based routing and flow control is more suitable for reliable transmission of bursty data traffic than to delay-sensitive but loss-tolerant real-time traffic