This informational message appears as the Border Gateway Protocol (BGP) neighbors go up or down. It shows that a BGP neighbor has either come up or gone down. The message describes the change that has occurred. This message appears only if the log-neighbor-changes command is configured for the BGP process.
This informational message normally appears as routers and BGP neighbors go up or down. However, unexpected neighbor loss might indicate high error rates or high packet loss in the network and should be investigated.