Forming Bgp Peer Routers; Static Peers - Lenovo RackSwitch G8264CS Application Manual

Forming BGP Peer Routers

Static Peers

© Copyright Lenovo 2017
Two BGP routers become peers or neighbors once you establish a TCP connection
between them.You can configure BGP peers statically or dynamically. While it may
be desirable to configure static peers for security reasons, dynamic peers prove to
be useful in cases where the remote address of the peer is unknown. For example
in B‐RAS applications, where subscriber interfaces are dynamically created and the
address is assigned dynamically from a local pool or by using RADIUS.
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.
You can configure BGP static peers by using the following commands:
RS 8264CS(config)# router bgp
RS 8264CS(config-router-bgp)# neighbor <1‐96> remote-address <IP address>
RS 8264CS(config-router-bgp)# neighbor <1‐96> remote-as <1‐65535>
RS 8264CS(config-router-bgp)# no neighbor <1‐96> shutdown
Static peers always take precedence over dynamic peers. Consider the following:
 If the remote address of an incoming BGP connection matches both a static peer
address and an IP address from a dynamic group, the peer is configured
statically and not dynamically.
 If a new static peer is enabled while a dynamic peer for the same remote address
exists, BGP automatically removes the dynamic peer.
 If a new static peer is enabled when the maximum number of BGP peers were
already configured, then BGP deletes the dynamic peer that was last created and
adds the newly created static peer. A syslog will be generated for the peer that
was deleted.
Chapter 28: Border Gateway Protocol
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