There is already RFC 7606 (Revised Error Handling for BGP UPDATE Messages), which specifies in detail how broken BGP messages should be handled. The most commo

There is already RFC 7606 (Revised Error Handling for BGP UPDATE Messages), which specifies in detail how broken BGP messages should be handled. The most common approach is 'treat-as-withdraw', i.e. handle the update (announcement of a route) as if it was a withdraw (removal of previously announced route). You should not just drop the broken message as that whould lead to keeping old, no longer valid state.