From securityboulevard.com
BGP does a great job of identifying optimal paths across the internet, but its lack of security controls allows the protocol to be exploited.
Whenever someone asks me, “What is border gateway routing protocol (BGP)?” I always use the following analogy to explain it: BGP is like the postal service. When you address a letter and drop mail in your mailbox, it gets mailed to the destination by using people, trucks, airplanes or sorted in postal facilities. BGP works the same way but it travels across the internet, is much faster and instead of airplanes or postal facilities, routers, circuits and central offices are used to reach its destination.