STP lab problem

[rai_praveen]

today i am doing STP lab on packet tracer and face some problem.problem is i create redundant topology through 3 switch and create one vlan number 5 in every switch.when i left all things for STP default or make manually any switch root bridge from root primary command all works fine but when i change STP mode to RSTP or disable STP on VLAN 1 then problem startand the problem is when i ping to pc it start pinging then suddenly when i break a link it will make block port in forward state then again when i connect the link with ports those port not shown in Show spanning tree command.i don't know why and RSTP behave wierd but when i do this switchport trunk allowed vlan 5 and remove vlan 1 from trunk thinks work fine port shown in Show spanning tree command.can any body tell me what's the problem

[cadet alain]

Hi,

please post a diagram and be clearer explaining problem.

But what I can say for sure is that disabling spanning tree is really a bad idea.

when i break a link it will make block port in forward state

you changed your spanning-tree topology which is normal behaviour.

when i connect the link with ports those port not shown in Show spanning tree command

what do you mean by that? if you disabled spanning-tree then if the only vlan was vlan1 it's normal they don't appear in spanning-tree anymore.

Regards.

Alain.

[Ganesh Hariharan]

today i am doing STP lab on packet tracer and face some problem.problem
is i create redundant topology through 3 switch and create one vlan
number 5 in every switch.when i left all things for STP default or make
manually any switch root bridge from root primary command all works
fine but when i change STP mode to RSTP or disable STP on VLAN 1 then
problem startand the problem is when i ping to pc it start pinging then
suddenly when i break a link it will make block port in forward state
then again when i connect the link with ports those port not shown in
Show spanning tree command.i don't know why and RSTP behave wierd but
when i do this switchport trunk allowed vlan 5 and remove vlan 1 from
trunk thinks work fine port shown in Show spanning tree command.can any
body tell me what's the problem

Hi,

It should not happen like this genrally by default all vlan are allowed over the trunk so that stp packets can be excahenged between the switches ove vlan1 and they can decide which ports needs to be blocked and allowed as per the stp pirority of the vlan.

Try the test one by one like do with standard stp and check the topology what are all the ports are forward state and blocked state,if everythings is as expected then try to switch with RSTP mode and then see the results and then do failover testing where you can see with rstp it is taking less time.

Hope to Help !!

Ganesh.H

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