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New Member

LAN Restructure

Hi All

I am looking to restructure the LAN over xmas, and have designed a collapsed core topology. In the distribution layer, we have two 3550's with the emi image. At the access layer which services all 3 floors in our building, we have 2950's linked to both 3550's in the dist layer. On each access switch connecting to the dist layer, I am running uplink fast and this works well. I am also running backbone fast on all switches in the vtp domain. On the two 3550's in the dist layer, I am routing between vlans and running hsrp for all vlans. Having tested this in the lab, If a switch in the dist layer dies there is no disruption to service. The only potential 30 second disruption to service I have noticed is when the gig link between the two dist layer switches is unplugged. There is a 30 second delay whilst stp recalculates.

Just wondering if there was any way of getting around this, It tends to be 30 seconds when you unplug and 30 seconds when you plug in.

One other thing, in the access layer wiring closets, I have 4 or 5 switches in each, and will create a loop for resiliance. Again with this senario, there is a 30 second delay, is there any way of speeding this up.

Sorry for long post

Best regards

5 REPLIES
New Member

Re: LAN Restructure

Karl,

Yes, it is possible. However, if not implemented correctly, it can make a REALLY unstable network.

http://www.cisco.com/warp/public/473/122.html

New Member

Re: LAN Restructure

Corr thats sounds risky .... is that the only way

Thanks for reply

New Member

Re: LAN Restructure

It's the only way I'm aware of. I believe you can reduce the risks of the entire network dropping by using PVST or PVST+

New Member
New Member

Re: LAN Restructure

Thanks for replys

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