BGP Basics- Points to remember

BGP Basic Points

• BGP is called a path vector routing protocol.
• List of AS no associated with a BGP route is called AS_PATH.
• AS_Path provide shortest path and Loop Prevention
• i in the end of AS_PATH indicate that the path is terminating at an IGP.
• Load balancing works only in EBGP( i.e Maximum Path), IBGP can use only one path.
• BGP does not use periodic routing updates. Peers  use keepalive to ensure that the connection is live.
• BGP Use TCP threeway handshake and open a TCP connection to port 179 before establishing any BGP peer connection.
•   TCP does fragmentation, retransmission, acknowledgment, and sequencing functions necessary for a reliable connection for BGP .

• Next_hop must be reachable in order to install route into IGP routing table.
• During Summarization, Path detail (AS_PATH)  is lost.