Lab
8.4.3
Configure BGP Connectivity between 2 Autonomous Systems
Objective:
The student should be able to
configure external BGP between multiple Autonomous Systems.
Task:
Router A is your corporate router.
You are responsible for configuring the ISP routers as well as your
corporate router and ensuring that users on the corporate network
can see the Internet. For lab purposes, the Internet will be the
Ethernet interfaces on each of the ISP routers.
Situation:
Your company is now dependent on
e-commerce and has decided to have two connections to the Internet
going to 2 different ISPs. Your ISP has informed you that you have
to run BGP to make this work. The ISP has asked that you remove your
static route to them, and configure a BGP route in order to ensure
that everything is operation okay before you add the second ISP to
the equation.
ISP #1 has an AS number of 200 while
ISP #2 has an AS number of 400.
Implement the IP addressing scheme
as shown in the diagram.
Enable BGP routing with AS number
and assign neighbor relationship with ISP #1.
Configure router B in ISP #1.
Verify operation.
Repeat sequence for ISP #2.
Verify operation.
Steps:
Configure all interfaces on all
routers with the appropriate IP address and subnet mask. Don't
forget to issue the
no
shutdown
command as well!
Go to Router A. Issue the show ip
route command. Are there any routes in the routing table? If so,
which ones?
We are now going to
configure BGP on the corporate router. This is Router A. · To
turn on BGP routing, enter global configuration mode and issue
the following command:
routerA(config)# router bgp 300
Verify that you can ping the IP
address of the serial interface on Router B of ISP#1 from Router
A.
Could you successfully ping the
interface?
The next step is to define BGP
neighbors. To do this, return to the following mode and type the
command below.