Part 2: BGP You have a single multi-homed BGP connection to 2 ISPs. You want to
ID: 3866076 • Letter: P
Question
Part 2: BGP
You have a single multi-homed BGP connection to 2 ISPs. You want to load balance traffic to a specific destination but you have no control over what the ISPs are doing with that route as it traverses the network.
Assignment:
1. Nothing has been preconfigured for you.
2. Make the required physical connections as depicted in the diagram (below).
3. Configure the IP addresses as depicted in the diagram (begin with 192.168).
4. Configure eBGP as follows using the connected physical interfaces as update sources:
* R1 to R3
* R1 to R2
* R3 to R4
* R4 to R5
* R2 to R5
5. Add a loopback on R1 and R5 with addresses 1.1.1.1/32 and 5.5.5.5/32 respectively.
6. Pull these loopbacks into BGP using the network command, and no other networks afterwards.
7.Configure an outbound route-map on R5 to set the origin to “?” for all routes it sends to R2.
8.Configure an outbound route-map on R5 to set the origin to “e” for all routes it sends to R4.
9. Configure an outbound route-map on R2 to set the MED to 2 for all routes it sends to R1.
10.Configure an outbound route-map on R3 to set the MED to 3 for all routes it sends to R1.
11. Ensure R1’s BGP table reflects these updates, and ensure you have connectivity from 1.1.1.1 to 5.5.5.5.
Explanation / Answer
a single multi-homed BGP connection to two ISPs. You want to load balance traffic to a specific destination but you have no control over what the ISPs are doing with that route as it traverses the network! You helped the ISP build their network … but then they fired you and left you scratching your head trying to enable load balancing.
Hi. You actually may be doing everything right. I had a similar issue until I realized that router 5.5.5.5 and 1.1.1.1 may not know how to go back to interfaces they are being pinged from.
Let’s say, if you are trying to ping from R1 to 5.5.5.5 you are actually pinging from 192.168.12.1 or 192.168.13.1. R5 does not have a route to 192.168.12.0/24 and 192.168.13.0/24 networks so the ping must fail. It’s the same situation if you ping R5 from R3 or R1 from R4.
However, if you use this command on R1 you will get a successful ping.
Ping 5.5.5.5 source 1.1.1.1