A simple approximation to minimum-delay routing

Abstract

The conventional approach to routing in computer networks consists of using a heuristic to compute a single shortest path from a source to a destination. Single-path routing is very responsive to topological and link-cost changes; however, except under light traffic loads, the delays obtained with this type of routing are far from optimal. Furthermore, if link costs are associated with delays, single-path routing exhibits oscillatory behavior and becomes unstable as traffic loads increase. On the other hand, minimum-delay routing approaches can minimize delays only when traffic is stationary or very slowly changing.We present a "near-optimal" routing framework that offers delays comparable to those of optimal routing and that is as flexible and responsive as single-path routing protocols proposed to date. First, an approximation to the Gallager's minimum-delay routing problem is derived, and then algorithms that implement the approximation scheme are presented and verified. We introduce the first routing algorithm based on link-state information that provides multiple paths of unequal cost to each destination that are loop-free at every instant. We show through simulations that the delays obtained in our framework are comparable to those obtained using the Gallager's minimum-delay routing. Also, we show that our framework renders far smaller delays and makes better use of resources than traditional single-path routing.

A More Scalable Approach to Content Centric Networking

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Distributed advance network reservation with delay guarantees

“…The literature offers practical methods for preventing formation of loops in distributed algorithms without having to re-initialize the whole network [13,14]. However, most of the offered solutions are particularly based on shortest path (or minimum delay) routing optimization and either do not apply to or need a lot of modification to fit our scenario.…”

“…Refs. [13,14] introduce loop-free shortest path algorithms extended from the Bellman-Ford algorithm [3]. Specifically, Ref.…”

“…Ref. [14] defines a pair of invariant conditions called Loop Free Invariant (LFI) at each node based on its cost to destination and that of its neighbors. The LFI conditions prevent formation of transient loops.…”

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