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Load Sharing between Two links

I have a CISCO 6500 with multiple SUP cards( for redundancy) peering with two diffrent ISP for BGP v4.

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I understand i can share the inbound traffic using AS prepnding but how do i make outbound sharing work ?

I need both lines configured for redundancy and increased throughput..

I am getting default routes from both isp's .

1 Solution
pehalwaanAuthor Commented:
Is this which is required ?

router bgp 50
neighbor remote-as x
neighbor prefix-list denyall in
neighbor remote-as y
neighbor prefix-list denyall in

ip route
ip route

ip prefix-list denyall le 32
Try using this config:

router bgp 50
bgp bestpath as-path multipath-relax
maximum-paths 2
These are both good solutions.  Let me add to them.

pehalwaan's way is good for equal lines and doesn't require BGP.  Just make sure CEF is enabled so it will do per-destination load balancing.  You will also want to make sure you add SLA Tracking onto the "ip route" commands or else you'll get a black hole to half your routes if one of the ISP's goes offline.  This method also does not offer you any control over how much it load balances or if the best gateway is used for a particular customer.

JFrederick29's BGP method will work for BGP outgoing.  I would also recommend a higher level of quality control by adding OER into the mix.  It can be configured to use netflow and ICMP pings (passive and active monitoring) and will adjust which gateway is used by injecting new BGP routes.

OER introductory documentation can be found here:


It's a lot of pages, but don't let it get you down.  A final OER configuration usually isn't more than 20-30 lines of config.  Cisco is just very thorough in explaining it.
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