An Analysis of Memory Demand for Forwarding Engines in Core Routers
Jianwen Yang · Dianzi xuebao · 2008
All internet routers contain buffers to store packets.Selecting appropriate buffer size can not only ensure router performance,but can also contribute to reducing uncertainty in the internet.This paper aims to size buffers for forwarding engines known as the main part of a router.First,a high-speed pipeline which is designed for forwarding engines is presented,and its memory analysis model is also given,then,the memory demand of forwarding engines is analyzed under two situations:the forwarding capability being not less than and less than the input rate.Our analysis results and experiments both show that,when the forwarding capability is not less than the input rate,a forwarding engine only need to buffer a several packets of maximum length,when the forwarding capability is less than the input rate,a forwarding engine only needs to buffer about ten packets in the view of buffer use efficiency,and further increasing the buffer size will have little effect.