Tag: port

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Cisco Stackwise Port Flapping

I recently was confronted with a stack of six Cisco 3750X switches that were experiencing intermittent outages.  The symptoms were random, but included switches being removed from the stack randomly, PoE drops, and full blown switch crashes with reloads.  If anyone has worked with Cisco stacks, you know how long it takes the entire stack to reload and elect a new master.

Troubleshooting the situation, I found that the switch stackwise ports were flapping.  All of them were reporting up/down notifications at random intervals. Read More

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Cisco StackPower – Port Issues

I have recently been battling with Cisco Stackpower issues and commands that have been difficult to find. In one environment the company uses 3750X series switches exclusivly in large stacks to avoid a spending cap on single items. Instead of buying blade switches we stack 24 port gig PoE 3750X switches. As an added benefit, with Stackpower we can make the switches redundant without buying additional power supplies. They will also distribute power if PoE devices are unevenly distributed to one switch or the other. Unfortunately when configuring Stackpower, not all ports are active at first, and sometimes the power sharing mode may be configured as something other than “sharing” by default.

A good overview for Cisco’s Stackpower can be found here: Cisco Stackpower Whitepaper Read More