Proportional switching in FIFO networks

TL;DR

This paper introduces the Proportional Scheduler, a new FIFO network scheduling policy based on proportional fairness, which maintains maximal stability without needing route information, improving scalability over BackPressure.

Contribution

The paper proposes the Proportional Scheduler for FIFO networks, offering maximal stability without requiring route-specific information, unlike BackPressure, thus enhancing large network performance.

Findings

Proportional Scheduler achieves maximal stability region.

It does not require route information for scheduling.

Performance improves in large networks with minimal route data.

Abstract

We consider a family of discrete time multihop switched queueing networks where each packet moves along a fixed route. In this setting, BackPressure is the canonical choice of scheduling policy; this policy has the virtues of possessing a maximal stability region and not requiring explicit knowledge of traffic arrival rates. BackPressure has certain structural weaknesses because implementation requires information about each route, and queueing delays can grow super-linearly with route length. For large networks, where packets over many routes are processed by a queue, or where packets over a route are processed by many queues, these limitations can be prohibitive. In this article, we introduce a scheduling policy for FIFO networks, the Proportional Scheduler, which is based on the proportional fairness criterion. We show that, like BackPressure, the Proportional Scheduler has a maximal stability region and does not require explicit knowledge of traffic arrival rates. The Proportional Scheduler has the advantage that information about the network's route structure is not required for scheduling, which substantially improves the policy's performance for large networks. For instance, packets can be routed with only next-hop information and new nodes can be added to the network with only knowledge of the scheduling constraints.