Value,Name,Reference
0,BGP_NULL (DEPRECATED),[RFC6396]
1,BGP_UPDATE (DEPRECATED),[RFC6396]
2,BGP_PREF_UPDATE (DEPRECATED),[RFC6396]
3,BGP_STATE_CHANGE (DEPRECATED),[RFC6396]
4,BGP_SYNC (DEPRECATED),[RFC6396]
5,BGP_OPEN (DEPRECATED),[RFC6396]
6,BGP_NOTIFY (DEPRECATED),[RFC6396]
7,BGP_KEEPALIVE (DEPRECATED),[RFC6396]
8-65534,Unassigned,
65535,Reserved,[RFC6396]