07-20-2009 10:59 AM
Hello,
We recently setup CiscoWorks and we are constantly (about every 10 minutes, sometimes more frequently) getting notifications of "STP Topology Change". I checked the logs on the switches as well as HSRP and CPU utilization and port utilization. I don't see any evidence or possible causes of Topology changes. We do use VOIP phones. I'm wondering if the fact that all the access ports are actually trunk ports (VOIP and client PC) could be causing these alerts when machines are unplugged or turned off. Has anyone experienced this?
Thanks
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07-20-2009 11:11 AM
This is coming from DFM based on the reception of the topologyChange trap from the switch.
Typically, voice ports are not trunks, but rather one access port which can support two vlans (a primary and a voice). In this case, portfast should be enabled, and topology changes will not occur. For example:
interface FastEthernet0/1
switchport access vlan 30
switchport mode access
switchport voice vlan 20
spanning-tree portfast
spanning-tree bpduguard enable
end
07-20-2009 11:11 AM
This is coming from DFM based on the reception of the topologyChange trap from the switch.
Typically, voice ports are not trunks, but rather one access port which can support two vlans (a primary and a voice). In this case, portfast should be enabled, and topology changes will not occur. For example:
interface FastEthernet0/1
switchport access vlan 30
switchport mode access
switchport voice vlan 20
spanning-tree portfast
spanning-tree bpduguard enable
end
07-20-2009 11:34 AM
Thank you. Adding portfast and bpduguard is on the list of things to do in our next maintenance. = )
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