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New Member

BGP MultiHome

I want to use BGP Routing in my network .Also  i have  two WAN Link from two Different ISP's  need to treminate on  two different Router.

will  use  one link as active  and the other one  as passive  for  Internet access and  when the primary link goes down  traffic to the backup link.

please advice  the command for configuration  as i am new to BGP.

Thanks,

Saroj

6 REPLIES
New Member

BGP MultiHome

There are many different ways to achieve the same result in BGP, but to implement each requires a detailed in depth knowledge of the internal workings of BGP. Is this a real network or is this a test setup? There are a LOT of things that this configuration will depend on.

Thanks,

Adam

New Member

BGP MultiHome

This is  Real  network Setup.

please advice  me the command  for Mulihome configuration part.

Regards,

Saroj

New Member

BGP MultiHome

Saroj

As stated before, there are many different ways to do this.

1.

A) On your back up router, prepend your AS about 4-5 times to make that link look like it's farther away. Even when you do this, you may get some traffice coming in over that link.

B) Set your local preference for your outgoing traffic to prefer the active router over the standby. 

       Read more here:

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094431.shtml

2. If the factors fit your business, I would recommend making both of them being active with the following settings.

    - Both routers learn that service providers routers, and their customers routes

    - On the router you want the most traffic to go over, learn a default route from that provider.

    - On the router you want the least traffic to go over, prepend your AS 1 or 2 times.

Option #2 can give you and your customers a better experience. If they are serviced by the same provider, they go directly to you instead of to your other provider to get to you. You employee's will do the same if the resource is on that providers network, it will be a shorter path.

Scape

New Member

BGP MultiHome

when one  interface of the router configured as  active  where the primary Link is terminated   and  another router interface configured as passive where the backup link  terminated  .Both the liks are from Different ISP's.

so how   will the configuration  need on the backup router when the primary link down the backup up automitically.

Thanks,

Saroj

New Member

Re: BGP MultiHome

Just  i want to validate  I have a setup   both the Router -1 and   Router -2  configured BGP with same AS and both the RTR   interfcaes  in   passive mode   .  so when the link on Router -1  goes down  will the   passive   Interface ON RTR -2  UP and  route Traffice to Internet.?

New Member

BGP MultiHome

You would need to connect the two routers with IBGP so they know when one of the Internet links go down.

On the inside interface you should use HSRP on the inside interface while tracking the outside interface. This will shift the default gateway over to the standby router when it needs to go active.

BGP can be tricky and there are many ways to do what you want to do. Hopefuly you can use some info here and get it working

Scape

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