I am using using 2 nexus devices as a core which are configured in VPC and further connect downward with 2960 switches and almost 100 Vlan are configured, I am facing frequently TCN for all the Vlans, What might be the possible reasons for frequently getting topology changes.. Because it is sometimes creating problems while pinging both the cores says "Destination Host Unreachable" while both the Nexus HSRP are stable...
I can see the Root Bridge as Nexus Switches, but down switches are not in port channel they are standalone.. There are 4 - 2960 switches which are forming a ring ,,, Ring start connecting from Primary Nexus and terminating to Secondary Nexus Switch....
so if the down switch is not forming port channel toward the both NSK then you need to not config vPC from NSK toward the down SW, config normal trunk or port channel from each NSK toward down SW.
There is also a Server Farm Nexus and Catalyst Switches, which is connected via PortChannel no issue in that,, but the standalone switches are creating problems.
I have checked the logg in some switches Mac Flap for Vlan has been observed between port... Will it make any impact?
Sir, Very Well Explained, I am fully agree wid your point ... But customer recommend to configure all switches in Ring topology,,,, it was also working since 2 yrs, but facing issue since 5 days....
