A theory of multi-channel schedulers for quality of service

A computer network consists of a set of computing nodes interconnected via communication channels. It is commonly assumed that, for each pair of network nodes u and v, there is at most one channel from u to v. However, it is often desirable to have multiple channels between nodes. That is, for every pair of network nodes u and v, there may be multiple channels from u to v. In this paper, we consider the problem of providing deterministic quality of service guarantees when there are multiple channels between nodes. We show that any packet scheduling protocol that operates over a single channel can be modified to operate over multiple channels. In addition, this transformation increases the packet delay through the node by only a small amount. However, having multiple channels between nodes may cause packet reorder. This reorder significantly increases the upper bound on end-to-end delay. We show how this increase in delay is avoided through the use of efficient sorting techniques.