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New Member

BGP and Load Balancing

Helloo all,

Currently we have one router connected to two upstream providers running BGP. How can a make sure both links are utilized evenly. Checking both interfaces load, only one is used and the other does not appears to be used that much.

ant ideas on how to do this?

Regards,

Carlos Roque

Office of Management and Budget

Commonwealth Of Puerto Rico

787-725-2822

8 REPLIES
Bronze

Re: BGP and Load Balancing

Hi carlos

Do you get bgp informations from you providers or do you make you forwarding towards you provider based on a derfault route?

If you get the bgp information you can implement multipath bgp with the command "maximum-paths #" under router bgp #. Usually a router only takes the best bgp route into the routing table. (==> need sp. IOS)

The way back to you depends how you provide your information to the provider and how this one handles this information. so you maid have to talk with you provider.

Hope it helps

Roger

New Member

Re: BGP and Load Balancing

We get full routing table from both providers and only aggregate to them our block on a 19 bit mask.

Regards,

Carlos

Re: BGP and Load Balancing

BGP load balancing is not an easy thing to do. This is because the inbound path to your AS is determined by the Internet.

This decision can be influenced by the way you advertise your networks.

What you can do is to prepend one or more of your AS number when you advertise your own networks to the provider from which you see more traffic.

In this way the as-path attribute will be longer via that provider and some parts of the internet will choose the your other provider for the returning traffic.

This is on iterative process, you prepend one as #, apply it and see what effect it has on the traffic. If it doesn't work prepend two as#, and so on.

Prepending as numbers for a neighbor can be done using the neighbor route-map command.

In the route-map you will have to do a match ip address ACL# to select the neighbor and a set as-path prepend YOUR_AS#.

New Member

Re: BGP and Load Balancing

Thanks for the reply. I will check this option to see how it works.

Carlos

New Member

Re: BGP and Load Balancing

Are you running BGP on these connections and are the same or different ISP's?

New Member

Re: BGP and Load Balancing

Here are some decent articles to help you out:

http://www.cisco.com/en/US/tech/tk365/tk80/tech_configuration_examples_list.html

The relevant articles are number 5, 6, 9, and 10.

Hope that helps.

New Member

Re: BGP and Load Balancing

Thanks for your response. I will check the link during this week.

Carlos Roque

New Member

Re: BGP and Load Balancing

We have two connection to the Internet with two different services providers.

Both links are connected towards tow Tier 1 ISP's.

Regards,

Carlos Roque

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