Solved: Using BGP on Cable and DSL

angel-moon · ‎03-04-2009

Hello,

we have someone looking at doing GLBP on a router with connections to a Cable ISP and a DSL ISP. They want a seamless failover for outbound traffic whenever one link goes down.

Is there any advantage to running BGP and having a public AS number if neither ISP will advertise the others IPs?

The ultimate goal is to have the failover traffic on teh inbound side still be able to reach internal web servers that have teh public IP address of teh Cable provider if the cable link is down. I think a solution may be to use the router as the authoratative DNS server for the network and use a very short TTL so that if the Cable provider goes down the router sends out the DNS update to start using the DSL providers static IP to reach the web server. The problem is even using this method there could be a significant delay in the updates and the web server would be unreachable for severla minutes to several hours.

Any ideas on how to best accomplish this? All replsies rated! Thanks in advance!

JamesLuther · ‎03-04-2009

Provider Independant

This means that you own the IP space and can move it from one ISP to another.

Provider Allocated (PA) numbers are taken out of an ISPs main IP block and so you can't advertise this via another ISP.

View solution in original post

JamesLuther · ‎03-04-2009

Hi,

The normal way to provide this is using BGP and a PI address range. However it sounds like you're using your ISPs IPs?

So in short, apply for some PI numbers and a public AS number. If that's not possible then your DNS solution is probably the next best thing.

Regards

angel-moon · ‎03-04-2009

Thanks. We had planned to use the ISPs IPs. At the risk of sounding like the newbie that I am, a Pl number is.....?

JamesLuther · ‎03-04-2009

Provider Independant

This means that you own the IP space and can move it from one ISP to another.

Provider Allocated (PA) numbers are taken out of an ISPs main IP block and so you can't advertise this via another ISP.