need help on BGP load balancing between 4 links

[sohail161982]

Hello everyone

I need some help regarding BGP load balance and failover. Here is my scenario. I am currently connected with two upstream provider with four physical interface for failover/redundancy. Now I need to configure loadbalance with failover between those pair of interfaces. To make my scenario more clear please see the attached picture.

[Raju Sekharan]

Hi Monirul

1. you have 2 links to each ISP. Are you going to have peering using single IP address for these 2 links? Are you going to use any bundling on these interfaces?

2. Are you going to receive complete routing table from ISPs or default-routes?

3. Do you have your own public AS and do you need to advertise your rnage of Public addresses to outside?

Raju

[sohail161982]

Hi Raju

Please find the answer inline.

1. you have 2 links to each ISP. Are you going to have peering using  single IP address for these 2 links? Are you going to use any bundling  on these interfaces?

---Yes i am using peering IP for all the individual link. That means i have four peer ip.

---No I am not using any bundling on these interfaces right now.

2. Are you going to receive complete routing table from ISPs or default-routes?

---- I am receiving default route only.

3. Do you have your own public AS and do you need to advertise your rnage of Public addresses to outside?

---Yes i have my own AS along with /21 IP and I advertise them as per requirement.

[cadet alain]

Hi,

to load-balance outbound then simply configure maximum-paths 2 under BGP process

Regards.

Alain

Don't forget to rate helpful posts.

[sohail161982]

Hi Alain

Thanks for your reply. I need to load-balance my inbound traffic. Will "maximum-paths 2" accomplish the task ? I need failover and load-balance both. Currently I am doing manual inbound load-balance with prefix-list.

[cadet alain]

Hi,

no maximum-paths is only for outbound load balancing.

Regards.

Alain

Don't forget to rate helpful posts.

[Raju Sekharan · Accepted solution]

"maximum-paths 2" will load-balance only your outbound traffic. the load-balancing will be towards only one ISP

In-bound load-balanccing can be acheived to some extend by

1.dividing your /21 subnet to two /22 and avertise it to both neighbors

2. for one neighbor add extra as-path using as-path prepedning for one subnet of /22

3. for the other neighbor, advertise the other /22 with as-path prepend

This will help only  if you have good amount of traffic to both subnets of /22

Thank you

Raju

[sohail161982]

Thanks Raju its working. Initialy it was not working because of the prepending to same SP restriction on my upstram.

Thanks for your help.

Thanks

Sohail