STP help for new switch

[edongskiu]

hi, need some advice. My switch suddenly started to reboot by itself, i had it replaced with the same 2924 xl with 100 base-fx uplink, same ios then transferred the startup-config. after 1 week i replaced a hub then after 2 hours the segment where it is installed suddenly went down. I power cycled the hub and everything went to normal. i checked the new switch and found out that the vtp and stp is disabled.

when i activate the vtp and stp will it prevent the re-occurance of the problem? please advice.

might try:
vlan database
vtp client

then

config term
spanning-tree vlan 1 protocol ieee

*vtp is installed on all switched and STP is already enabled on the distribution layer where the new switch is installed.

please advice.

 

[plshlpme]

what is your scenario.. are there redundant links between your switches?

are you running multiple vlans between them?
if not you do not need spanning tree or trunking and something else is bringing your network to a halt. is it possible for you to replace your hub with another switch? because stp won't work on the hub and can still cause all kinds of storms on the devices that are plugged into it.

 

[edongskiu]

yes, i got redundant link between my switches ( 2 fddi) and i am running multiple vlans between them.

let me describe the scenario, sw 1 is one of the two main switch (distribution layer). then my old switch (sw3) started rebooting by itself and i replced it immediately with spare, same ios and model and module card and transferred the startup-config.

and i thought that a loop have brough my network down, though, i checked the distribution layer and has a running STP, must i activate the STP on sw3 or STP running on sw1 is enough?

 

[plshlpme]

well you will need stp running on all of the switches. by default i would think that cisco switches would have it on.

every switch needs to activly participate in the spanning tree though or else you will have problems.

 

[edongskiu]

If i activate the STP and VTP from the switch, would it cause downtime or unusual behavior in my network?

thanks.

 

[plshlpme]

no the convergence will be quick.. but are you using multiple vlans? if not you don't need vtp.. you only need to trunk when you have vlans across multiple switches.

 

[wybnormal]

remember that each VLAN has it's OWN instance of spanning tree running. You need to make sure everybody is on the same page. It also offers a way to load balance between redundent switches by using spanning tree and setting each VLAN with different root bridges. Of course, you really need to document when you are done

MikeS

http://www.packetattack.com

http://www.packetpress.net

Home of the book "Network Security Using Linux"

 

[ReadRight]

Also STP needs to be working specifically on any ports that can lead to other switches. Make sure you do not have portfast enabled on any of those interfaces.