Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

BGP Design

Dear All,

Currently we have one gateway router(7206) which is having Internet Connectivity from ISP-A , We have second Internet link which is connected to Second router(1700) which in different Location.

ISPA------- ROUTER1(7206)--------MICROWAVE------MICROWAVE------ROUTER2(1700) -------ISP-B

Now we have to run BGP in 7206 router only.How we can config Load balance & Fallback if any of link goes down.How 7206 will get BGP advertisement from router (1700) which is connected to ISP-b.Is it neccesary that routers must be directly connected??

TIA

Regards

SAM

4 REPLIES
Hall of Fame Super Silver

Re: BGP Design

Sam

To come up with a really good design would require knowing some things about your network that you have not told us. But based on what you have provided here I have the following advice:

- It is not necessary that your 7206 and your 1700 be directly connected. They will run a BGP session between these routers and it will be an IBGP session (both routers in the same AS). It is not necessary for IBGP peers to be directly connected. The connection between 7206 and ISPA and the connection between the 1700 and ISPB are dirrectly connected and will be EBGP sessions. It is generally better if EBGP peers are directly connected.

- I would be very cautious about running BGP on the 1700. The memory requirements and the processing requirements for participating in Internet BGP can easily be greater than the capability of the 1700. I would suggest that the 1700 only accept a default route from ISPB. That will greatly reduce the memory requirement and the processing requirement on the 1700.

- I am not sure that I would want to load balance between the 7206 and the 1700. I might prefer to have the 7206 be primary and handle all the Internet traffic if it were available and use the 1700 as fallback if needed. But if you want to do load balancing I would have both the 7206 and the 1700 receive only a default route from their ISP. They can make their version of the default route available to their part of the network. And if one of the routers failed you could have that part of the network use the default route from the other router. The details of how to do that would depend on what interior routing protocol you are running.

HTH

Rick

New Member

Re: BGP Design

Thanks Rick for your quick reply.

Currently BGP works on 7206 router only.I am not planning to run BGP on 1700 router as this is very lower end router.But problem is that i have one Internet connection from ISP-1 which is terminated on 7206 which is fine.But second internet link which is terminated on 1700 router which is not in same premises of 7206.Two mirowave link with routers comes in between 7206 & 1700.Though 1700 is directly connected to ISP-2 but due to memory problem i cant run BGP in that.To avoid this problem i am using 7206 for all BGP config.How BGP will work in fallback & normal scenario.

Waiting for your reply.

TIA

Regards

SAM

Purple

Re: BGP Design

Hi Sam,

What you would need to do is redistribute your default routes into your IGP on both the 7206 and the 1700. Make the default route injected on the 1700 less preferable by assigning a worse metric than the one of the 7206. When the 7206 link goes down, the default through the 1700 will still be available as a backup.

Hope that helps - pls rate the post if it does.

Paresh

New Member

Re: BGP Design

Thanks Paresh,

Let me try this config in my LAB then i will let u know result.Can u please give some link where i can get this nework Scenario.

TIA

Regards

SAM.

123
Views
7
Helpful
4
Replies