see attachment - I have 3 switches. 2 core and 1 access layer. access1 connected to both cores via a single dot1q trunk. vlan 175 active on all switches. according to spanning-tree the root port (gi0/1) is towards CORE1 on access1 and blocking port (gi0/2) to CORE2. the problem is when the HSRP state changes between the CORES, say CORE2 is now the active HSRP peer, spanning-tree topology stay the same and traffic from access1 to CORE1 is blackhole. access1 cannot no longer access anthing on the network and the mac address for 192.168.175.254 is still pointing to CORE1 via gi0/1. any suggestions how to rectify this behaviour?