BGP Load Balancing & Fail Over

[bilalfayyaz]

Hi,

We have a situation, Our Company got our own AS number with three our own /24 Subnets, and we are peering with 2 different ISP's and receiving only default routes.

We want to advertise our 3 subnet from both ISP for load balancing & fail over , two subnets will be preferred from one ISP link for incoming & outgoing traffic and one subnet will be preferred from second ISP for incoming & outgoing traffic by prepending AS-Path attribute.

With this configuration, we are able to browse all web sites except our countries web sites. Looking like Asymmetric routing is causing problems.

Now your help is required to solve this problem or someone can suggest any good design for BGP load balancing & fail over.

Subnets:

1.   X.X.22.X/24

2.   X.X.24.X/24

3.   X.X.25.X/25

Rough Topology Diagram is attached for understanding.

Thanks in Advance.

Bilal.

[cflory]

Here's a link that may help:

http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00800945bf.shtml

[Marwan ALshawi]

Check with each ISP where you want the advertised network to be less preferred how it's being treated with the ISP itself as ISPs they use bgp community strings to make a certain route preferred over same ISP for that ISP customers and this could be the reason !

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