do you use a fiber connection between the Extreme and Cisco switches? If so, activating UDLD on the Cisco is problematic, because it is a Cisco proprietary feature that does not work with other vendors' switches.
Using Ethernet flow control (active on the Cisco) is not a good idea in general, it might cause intermittent problems, like dropping one ping packet or the other.
The "keepalive 30" setting on the Cisco is dubious as well, as this should enable a Cisco proprietary keepalive mechanism, but the EXOS switch does not send responses.
Since you have configured BPDU Guard on the Cisco, you must not enable STP on the EXOS switch. You can check if BPDU Guard error disabled an interface using "show interfaces err-disable."
they resolved issue
they had the switches stacking enabled but they did not have any physical connections via the stacking cable to any other node
they used the below command so that the MAC address will get configured automatically.
"configure stacking mac-address"
Hi Siva, If i understood correctly although the switches have stacking enabled they do not have any physical connections via the stacking cable to any other node (switch). If yes then the given command will only change the MAC address.