I am having a problem with spanning tree on my network. The network consists of two gigabit ethernet rings with cisco 2950 switches connected to a cisco 3550 switch for aggregation. There are three vlans configured on the switches. Spanning tree is blocking a port on the farthest switch in the ring so as not to create a loop condition and providing redundancy. However, I have been having ports on other switches in the ring going into error-disable and the log message is "loopguard is blocking port
gig-x on vlan x , the spanning tree message age timer expired and no bpdu's were recieved from the designated bridge". Sometimes this will happen on a couple gigabit ports at the same time dropping several nodes on the ring simultaniously. Why are these ports not recieving Bpdu's before the timer expires? This happens about once a week or so.
