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Switch Installation

Paul Munro_1
Occasional Contributor

Switch Installation

Hey- feel greedy having just posted...

We installed one of our 2626 switches in bog standard default configuration (plug and play) at work and when we did so lost log on connections in another (I assume separate) collision domain. Now I say "assume" because my hunch is:

1. The new switch had to take a short amount of time to build its table of addresses to know where to switch frames to;

2. My hunch is that the other segment was connected to the room we were upgrading with the new switch.

Or am I missing something about installing these that I should know? I thought that installing the new switches in default configuration status would mean just putting them in and working as normal. But as it happened, both segments lost the ability to log on to the domain controller for about 30 minutes in the end. After that- for some unknown reason- they were fine!

Sorry to ramble. Any thoughts on this would be appreciated.

Thanks again,

Paul
1 REPLY
Ernest Ford
Trusted Contributor

Re: Switch Installation

Does "bog standard default" configuration include STP (spanning tree protocol)? Are there redundant links between the old switch and the new switch? Are there more than just the two switches mentioned?

In your post you use the terms "segment" and "collision domain" in a manner that suggests you may not be familiar with them.

With an ethernet switch, each cable drop (between the switch and the attached host) is a separate segment or collision domain. Switches break up collision domains but not broadcast domains and redundant (or multiple) links between the switches cread broadcast loops which STP is designed to control.

The time taken for STP equipped switches to converge can be appreciable, especially if all the switches are in the default configuration - in which case the "root bridge" will be dictated by the MAC addresses of the swiches.

The more switches there are, the longer it takes to converge, but, as you discovered it will eventually settle down and become operable.