I have several Cisco 3750's being trunked into an AVAYA P332 Core. Lab tests go great and all 7 vlans are interconnected.
Configuration is a basic..
switchport trunk encapsulation dot1q switchport mode trunk
Native vlan is 1. Avaya is base dot1q - no leaky vlan configured
All etherchannels/hunt groups removed.. vlans matched for SAID's on both sides. Place this onto the operaional network and boom! Network down.. symptoms were intermittent pings to all devices and user application failure site wide..
Remove 3750 and all is restored. Interface counters on the 3750 for couple minutes showed:-28700430 packets input, 1951804052 bytes, 0 no buffer Received 28699747 broadcasts (0 multicast) 0 runts, 0 giants, 0 throttles 326 input errors, 7 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 28697164 multicast, 0 pause input 0 input packets with dribble condition detected 5451 packets output, 774332 bytes, 0 underruns 0 output errors, 0 collisions, 2 interface resets
Back to the lab..
In the lab we then removed all STP (its not needed), DTP, VTP, CDP & UDLD. This is now just a dot1q trunk.. nothing more!
Then it was noted that the Avaya is encapsulating its native vlan so this has been matched on the Cisco with the global [vlan dot1q tag native] command...
It is now at the stage of re-testing.. and I have only one shot at it for an hour this weekend on the ops network.. have I missed anything? Does anyone have any prior experience of Avaya/Cisco trunk issues? What else could possibly be causing this trunking failure?