Posts Tagged ‘flow control’

PowerShell: Query Cisco (Catalyst 4500) Flow Control statistics

Written by Ingmar Verheij on June 1st, 2012. Posted in PowerShell

Last week I attended E2EVC in Vienna, a non-commercial,virtualization community Event, and attended a session of Saša Mašić about an issue he had at a customer. In short, the problems where caused by a switch that couldn’t process IP packets because it overflowed, and therefore Ethernet flow control temporarily stopped the transmission of some attached devices. Although I’m no network expert I do know this might be a serious issue. After reading this article, you might agree.

If you’re looking for the PowerShell script, scroll to the bottom.

RxPause and TxPause

This week I  was asked to troubleshoot performance issues at a customer and got informed that the core switches (Cisco Catalyst 4500) might be over capacity. A quick look in the flow control statistics (# show flowcontrol) indicated there where send numerous RxPause and TxPause packages, a sign Flow Control has been active.

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