I have a question about STP.
STP (rstp) is enabled on several switchs for a vlan which doesn't need it (there are no loops possible). On this vlan there are edge ports which doesn't have the portfast option activated.
Each time I plug or unplug a port in this vlan, I have a quite (30 sec) long outage due to the recomputation of the STP protocol.
My question : I would like to solve this problem, either by disabling STP for this vlan, either by setting the portfast option on the edge ports.
What is the best way to solve the problem, without generating a new outage ?
In other words, can I desactivate the STP (one switch after the other) without generating an outage. And can I set the portfast option on a port without generating an outage.
Thanks a lot
It is a BAD practice to disable STP. STP has very little bandwidth overhead and can save you from a disaster. I would not disable it.
Simply add portfast to the access ports, as the gentlemen have described, and then enable bpduguard.
1. I think it is better to use portfast (with bpdu guard)instead of turning off the stp in that particular vlan. In that case portfast will not cause any outage as it puts the port into forwarding state as connected but still prevent from bridging loop to occur if inadvertently connect a switch as stp takes care of that.
2. In order to disable stp per vlan and let run in others obviously needs pvstp (per vlan stp) and will not cause outage if disabled per vlan.
You can configure edge "access" ports for portfast option without any outage.
use this command "spanning-tree portfast" under interface config.
along with that I will recommend to use
"spanning-tree portfast bpduguard default" in global config.
So that BPDU-guard is enabled on the portfast enabled interfaces, in case another switch is connected to any of the portfast interface by mistake , the concerned interface will be disabled.