Transit AS Routing

Scenario You are a network administrator for an ISP with autonomous system number 200.. Your autonomous system is multi-homed to various customers including AS 100 for the International

1-2 Semester 8 Internetwork Troubleshooting v1.0 - Lab 14.3.3.2 Copyright  2001, Cisco Systems, Inc

Lab 14.3.3.2: Transit AS Routing

AS200

Fa0/0 10.1.1.2/24 S0/0

DCE .1

.2 S0/0

Fa0/0 192.168.0.1/24

AS100

ISP1A

SanJose1

10.0.0.0/30

ISP1B

Fa0/0 10.1.1.1/24

IBGP

Objective

Successful propagation of customer routes through IBGP

Scenario

You are a network administrator for an ISP with autonomous system

number 200 Your autonomous system is multi-homed to various

customers including AS 100 for the International Travel Agency (ITA)

Routers running IBGP within AS 200 cannot reach AS 100

Step 1

Cable the lab as shown in the diagram

Load the configuration files into your routers

2-2 Semester 8 Internetwork Troubleshooting v1.0 - Lab 14.3.3.2 Copyright  2001, Cisco Systems, Inc

Step 2

Start the investigation on router ISP1B with show ip bgp, show ip route and show ip bgp 10.1.1.2; record results below:

Step 3

Based on the output and your knowledge of BGP, what are some possible causes for routers from other autonomous systems cannot reach AS 100?

Step 4

What is your action plan for allowing traffic originating in or transiting AS 200

to reach AS 100?

Step 5

Implement your action plan and observe results with show ip bgp, show

ip route and show ip bgp 10.1.1.2 Also, ensure connectivity with

a ping from router ISP1B to the remote LAN in AS 100

Step 6

Document summary of problem, troubleshooting methods and resolution