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Minimal Configuration
Once you have collected this information, you are ready to begin the BGP
configuration process. Since BGP is very complex, it is best to learn it by
starting with a very basic configuration. Our example does not have real-
world applicability, but by doing it this way, we will see how to work with
the basic functions of BGP.
Let's look at Figure 8.1, which shows a very simple configuration of BGP.
If you can get this configuration to work, you should be able to understand
how to create more complex configurations of BGP. The network
is real. I added routers to simulate the and networks.
T A B L E 8 . 1
BGP Router Checklist Information
BGP needs a router ID. This can be the
address of the loopback interface or the
IP address of a directly connected interface.
This ID is usually the IP address of the
loopback interface, making the interface
easy to identify.
BGP process number
Our assigned autonomous system number
(ASN) or a private ASN.
We will assign those in our own AS, but the
service provider should provide you the
addresses and ASNs under the provider's
NLRI (Network Layer
Reachability Information)
to advertise
These are our assigned ASNs that need to
be advertised over the Internet.
Filters/policy mechanisms
Our internal routing policy.
With BGP, you also need to specify the
peers. Peers are not automatically
discovered. This is a matter of intentional
protocol design, not a limitation. Peers are
other routers running BGP.
Copyright ©2001 SYBEX , Inc., Alameda, CA