The peer index. The peer index is a unique index for the peer entry in the bgpPeerStatusTable. It is used to provide an index value for other tables whose data is logically per-peer. The peer index value is fixed until the entry in the bgpPeerStatusTable is destroyed, but it changes if the entry is destroyed and recreated. For a dynamic BGP peer, if the BGP session terminates and then restarts outside the graceful restart period, the bgpPeerStatusTable entry is destroyed and then re-created, causing the peer index value to change.