Hello Engineers,
I am arguing with psvt+ protocol.
Our company using two different switch (Cisco, ExtremeNetworks) and most of switches are Cisco's.
Switches are enabled pvst as a default for the Cisco switches.
Yesterday there was a loop issue, I noticed that because one of VLANs is down.
Core switch logs are full of 'flapping error msgs', about issued vlan and CPU was almost 100 percent.
Weird thing is, l guess loop connection has been made few hours ago, but Core switch stopped entire traffics of issue vlan few hours later. Is it possible?
I am guessing the loop was started like that.
However, if L2 switch is enabled pvst+ protocol, switch realized that two ports(access mode) are made a loop.
So, L2 switch should've disabled one of port.
But, two ports of L2 switch are connected state, and there was no record about blocked port.
When I checked the CPU history, it goes up to 70-80(maximum) but it is low percentage comparing with Core switch.
Am I wrong about the pvst protocol? or Do you think there might be different loop case?
Please save me from the loop maze....
