This article provides information about the BGP Notification Code 6 (Cease) Subcode 2 (Administratively Shutdown) and its impact, including the transition of the BGP session from Established to Idle state.

Below mentioned BGP logs will be seen during the issue.

Feb 25 23:14:30 <Device> <Device>: rpd[31635]: %DAEMON-4: bgp_handle_notify:4587: NOTIFICATION received from x.x.x.x (External AS yyyy): code 6 (Cease) subcode 2 (Administratively Shutdown) 

Feb 25 23:14:30 <Device> <Device>: rpd[31635]: %DAEMON-4-RPD_BGP_NEIGHBOR_STATE_CHANGED: BGP peer x.x.x.x (External AS yyyy) changed state from Established to Idle (event RecvNotify) (instance master)

This BGP notification states that if a BGP speaker decides to administratively shut down its peering with a neighbour, then the speaker SHOULD send a NOTIFICATION message with the Error Code "Cease" and the Error Subcode "Administrative Shutdown" suggest that the remote peer has deliberately terminated the BGP session, due to some activity. BGP flapping between the peers will be observed.

For more details about the notification, please refer RFC4486. According to RFC4486, when a BGP speaker decides to administratively shut down its session with a neighbor, it SHOULD send a NOTIFICATION message with Error Code “Cease” and Error Subcode “Administrative Shutdown”.