Lenovo Flex System Fabric CN4093, Application Manual

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© Copyright Lenovo 2017 Chapter 29: Border Gateway Protocol
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Forming BGP Peer Routers
Two BGP routers become peers or neighbors once you establish a TCP connection
between them. For each new route, if a peer is interested in that route (for example,
if a peer would like to receive your static routes and the new route is static), an
update message is sent to that peer containing the new route. For each route
removed from the route table, if the route has already been sent to a peer, an
update message containing the route to withdraw is sent to that peer.
For each Internet host, you must be able to send a packet to that host, and that host
has to have a path back to you. This means that whoever provides Internet
connectivity to that host must have a path to you. Ultimately, this means that they
must “hear a route” which covers the section of the IPv4 space you are using;
otherwise, you will not have connectivity to the host in question.