Lab Objective:
The focus of this lab is to understand BGP implementation and configuration in Cisco IOS routers. Additional technologies include route filtering, summarization and path control.
Lab Topology:
The lab network topology is illustrated below:
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IMPORTANT NOTE If you are using the www.howtonetwork.net racks, please bring up the LAN interfaces connected to the routers by issuing the no shutdown command on the connected switches. If you are using a home lab with no Switches, you can bring up the LAN interfaces using the following configurations on your routers: interface fastethernet 0/0 no keepalive loopback no shutdown Alternately, you can simply connect the interfaces to a hub or switch if you have one available in your own lab. |
Task 1
Configure hostnames and IP addressing on all routers as illustrated in the network topology.
Task 2
Configure BGP as illustrated in the topology. R1 will peer with R2 and R3. R2 will peer with R1 and R3. R3 will peer with R1, R2 and R4. R4 will peer only with R3. The routers should all use their physical interface addresses for BGP peering. Verify your configuration.
Task 3
Advertise the 150.x.x.x LAN subnets on all routers via BGP. These should be injected using the network command on all routers. Verify that all routers’ LAN subnets can ping every other routers LAN subnet. Use an extended ping to perform this verification.
Task 4
Configure R1 with the following Loopback interfaces:
Loopback 1920: IP Address 192.0.0.1/32 Loopback 1921: IP Address 192.0.1.1/32
These prefixes should be advertised only to R2. Next, configure R2 to advertise a single route for these prefixes to R3. Ensure that this aggregate route ONLY appears in the BGP Table of R4 but not in the BGP Table of R1. Adhere to the following restrictions when completing this task:
- You can NOT use an outbound route map on R1
- You can NOT use any outbound filters or route maps on R2 or R3
- You can NOT use any inbound filters or route maps on R1 or R3
- You can NOT modify administrative distance values
Verify your configuration using the appropriate commands. Verify that R2, R3, and R4 can ping these prefixes from their LAN subnets, i.e. the 150.x.x.x/24 addresses.
Task 5
To support a future Anycast solution, configure R2 and R4 with a Loopback 200 interface with the IP address 200.8.8.8/32. Next, redistribute this prefix into BGP on R2 and R4 and configure BGP path control so that R1 prefers the prefix originated by R4 over the prefix originated by R1. However, you must adhere to the following restrictions when completing this task:
- You can NOT modify the AS_PATH length for this prefix on ANY router
- You can NOT modify default administrative distance values
- You can NOT modify the WEIGHT or LOCAL_PREF attributes on R1
- You can only issue ONE single command on R1, i.e. one line of code
- You MUST use route maps when redistributing this interface on R2 and R4
Verify your configuration using the appropriate commands. Ensure that R1 can ping this address from its LAN IP address of 150.1.1.1/24.