spanning-tree mode rapid-pvst ???

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Jul 10th, 2007
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Hello. Thanks in advance for any help someone can give. I will be working on adjusting configs for 11 switches we have in an elementary school in our district. The core switch is a Cat3750 and other access switches are 3560's, 3550's and a few 2950's I believe. My initial question is about spanning-tree mode rapid-pvst. The current config on the 3750 is "....mode rapid-pvst". I received basic configs from an engineer who is redoing our other school locations. His sample has spanning-tree mode pvst. Should I use that command instead. Do all of the models of switches I listed support both of these commands and or can they play nice if one or the other commands is programmed on the switch. In other words, the rapid-pvst command is on some and the plain old mode pvst command is on other switches. Thanks in advance for any help you can provide.

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royalblues Tue, 07/10/2007 - 06:11
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rapid pvst or RSTP helps in faster convergence than traditional PVST.

The 3560 and 3750 support RSTP even in the IP base image

2950 switches require EMI image for RSTP support

If all your switches support RSTP, i would suggest configuring it, otherwise go with PVST



trptplayer1 Tue, 07/10/2007 - 06:57
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Thanks for the info. I may stick with PVST for now and migrate over to RSTP.

Question, how do I check for sure if I have the EMI image on the switch? Do I just run the "show version" command?



Jon Marshall Tue, 07/10/2007 - 06:14
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Attached is a link to a doc which has Catalyst switch support for RSTP.

You can run PVST+ and RPVST+ in the same switched network without issues although you need to be aware that if you have a vlan that spans switches some of which run RPVST+ and some of which run PVST+ then it will default to PVST+ timers ie. approx 45 seconds in total.



trptplayer1 Tue, 07/10/2007 - 06:50
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Thanks for the info. I'll check it out. I'm probably leaning towards the PVST for now. If the convergence timers are approx 45 seconds, that is not a problem for us.



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