Part1: BGP Lab Setup I. Topology
II) IP address Table
Lab 4: BGP Aggregation, Multihoming and Backup links
Figure 1 – BGP Lab Topology
Router
IP Address of s2/0
IP Address of s2/1
IP Address of e0/0
IP Address of e0/1
Loopback 0
R1
176.1.1.1/24
–
10.1.1.1/24
10.1.1.0/24 Net1
–
R2
176.1.2.2/24
–
10.1.1.2/24
10.1.3.2/24
R3
10.1.4.3/24
–
–
10.1.3.3/24
10.1.2.3/24
10.1.2.0/24 (Net2)
R4
176.1.1.4/24
–
–
176.1.3.4/24
176.1.3.0/24 Net3
–
R5
176.1.2.5/24
176.1.4.5/24
–
176.1.3.5/24
–
R6
10.1.4.6/24
176.1.4.6/24
–
–
192.168.1.6/24
192.168.1.0/24 (Net4)
III) Configuration
1. Run EIGRP in AS100. EIGRP should carry all the routes in 10.1.0.0/16. 2. Setup BGP connections to the following router pairs.
R1-R2; R1-R3; R2-R3; R1-R4; R3-R6;
R4-R5; R5-R6;
router bgp
neighbor
Use additional neighbor ip-address next-hop-self command for the appropriate IBGP connections.
3. Use the network command in the routers to advertise networks 1, 2, 3 and 4 to their BGP peers. Do not use redistribution.
router bgp
network
example:
router bgp 45
network 192.1.1.0 255.255.255.0
4. Disable link R5-R2.
5. Configure no synchronization in all the BGP processes.
router bgp
Part2: Aggregation
Objective: To study various aggregation methods and investigating the configuration where neighboring AS (service provider) uses more specific routes while other AS uses the aggregated route
A) Static Route Approach
1. Use the original network setup with the following modifications: link R3-R6.
2. Configure R1 to aggregate the routes in AS100 and advertise only the aggregated route to AS200. Use the static- route approach.
3. Verify your configuration by examining the bgp and routing tables of R4, R5, and R6.
B) Aggregate Plus More-Specific Routes
1. Keep link R3-R6 disable.
2. Enable the link and configure BGP connection between R2 and R5.
3. Configure send-community option in R4 for the BGP connection between R4 and R5.
4. Configure R1 and R2 to satisfy the following conditions:
a) Both routers advertise the aggregated route (10.1.0.0/16) and specific routes (10.1.1.0/24 and 10.1.2.0/24).
b) R6 only learns the aggregated route to reach AS100.
c) AS200 uses R2 to reach Net2 (10.1.2.0/24), and R1 to Net1 (10.1.1.0/24)
Design 1: Use route-map and community commands for the configuration.
Design 1: If you configure the routers correctly, they will learn all the routes. Record your configuration. (note: the network address of the serial links that are not required to learned by all the routers)
Q: In your configuration, you need to setup a static route: ip route 10.1.0.0 255.255.0.0 null 0 Explain how this setup works
Part 3: Multihome to Different Providers
Objective: To setup primary and backup routes.
1. Use the original network setup.
2. Consider the following set of conditions:
a) For outgoing traffic, link R1-R4 is the primary link (link R3-R6 is the backup link).
b) External traffic to Net2 prefers link R3-R6.
c) External traffic to Net1 prefers link R1-R4.
d) AS100 is a nontransit AS.
e) All the networks can be reached by the routers.
Part 4: Private and Backup Links
Objectives: To setup a private link. To configure the private link as a backup link.
1. Use the original network setup with the following modifications:
• Configure R3 such that R3 and Net2 belong to AS400.
• Disable the BGP connection between R3 and R1.
• Disable the EIGRP processes in R1, R2, and R3.
• The BGP connection between R2 and R3 is and external connection.
2. Consider the following set of conditions:
a) Link R2-R3 is used as a private link for the traffic between AS100 and AS400.
b) Other traffic of AS100/AS400 uses the service provider link (AS200/AS300).
c) If the service provider link is down, AS100/AS200 will use the private link to send and receive external traffic.
Design 1: Configure the routers in your pod to satisfy the above conditions. Disable some primary links and test if the backup links function properly.
Design 1: Configure the routers in your pod to satisfy the above conditions. Disable the service provider link and test if the private link function as a backup.