Providing Rate Guarantees to TCP over the ATM GFR Service

TL;DR

This paper explores how to provide rate guarantees for TCP traffic over ATM GFR service using buffer management, demonstrating that FIFO queues can be effective under low buffer conditions through analysis and simulation.

Contribution

It introduces a buffer management policy that offers loose rate guarantees for TCP over ATM GFR with low buffer allocation, challenging the need for per-VC queuing.

Findings

FIFO queuing can control TCP rates under low buffer conditions.

The proposed buffer management policy provides loose rate guarantees.

Simulation confirms effectiveness of the buffer management scheme.

Abstract

The ATM Guaranteed Frame Rate (GFR) service is intended for best effort traffic that can benefit from minimum throughput guarantees. Edge devices connecting LANs to an ATM network can use GFR to transport multiple TCP/IP connections over a single GFR VC.These devices would typically multiplex VCs into a single FIFO queue. It has been shown that in general, FIFO queuing is not sufficient to provide rate guarantees, and per-VC queuing with scheduling is needed. We show that under conditions of low buffer allocation, it is possible to control TCP rates with FIFO queuing and buffer management. We present analysis and simulation results on controlling TCP rates by buffer management. We present a buffer management policy that provides loose rate guarantees to SACK TCP sources when the total buffer allocation is low. We study the performance of this buffer management scheme by simulation.