General
Any other 9800 will work without issues, the controller was upgraded from 17.9.3 to 17.9.4a
Symptom
Every time the 9800-80 is added the anchor on the specific site starts making all the mobility tunnels fail and as soon as it is removed everything starts working
Conditions
We see the following meesages on the 9800-80:
an 19 21:56:30.962: %MM_NODE_LOG-4-PMTU_FAILED: Chassis 1 R0/0: mobilityd: Capwap path MTU discovery error: Pmtu ack message not valid, pmtu xid do not match
Jan 19 21:56:30.962: %MM_NODE_LOG-3-PING_DROPPED: Chassis 1 R0/0: mobilityd: Drop data ping from IP: 10.109.40.28. Unable to handle pmtu ack
Jan 19 21:56:30.962: %MM_INFRA_LOG-3-MSG_PROC_FAILED: Chassis 1 R0/0: mobilityd: 380e.4d9c.24d9: Unable to process the received mobility message keepalive_data from ipv4: 10.109.40.28 . reason: Failed to handle the message
Jan 19 21:57:00.555: %SYS-6-LOGOUT: User AHSprime has exited tty session 2(10.133.66.190)
Jan 19 21:57:00.582: %MM_NODE_LOG-4-PMTU_FAILED: Chassis 1 R0/0: mobilityd: Capwap path MTU discovery error: Pmtu ack message not valid, pmtu xid do not match
Jan 19 21:57:00.582: %MM_NODE_LOG-3-PING_DROPPED: Chassis 1 R0/0: mobilityd: Drop data ping from IP: 10.109.40.28. Unable to handle pmtu ack
Workaround
The workaround suggested for the mobility is , change the Mobility MAC address in the 9800 to be lower than the rest of the controllers, the lowest MAC address will be the DTLS server and also the mobility capwap keepalives transmitter
Aireos 5520 Mobility MAC > 380E.4DXX.XXXX
9800 mobility mac from > 90eb.50XX.XXXX >>>> This can be changed to 20eb.50XX.XXXX
Further Problem Description
Workaround worked for the tunnels to be up
