Need provider suggestions - BGP transit over GRE tunnel

C. Jon Larsen jlarsen at
Sat Jan 29 11:06:34 CST 2011

On Sun, 30 Jan 2011, Franck Martin wrote:

> Just make sure you don't shoot yourself in the foot by telling the best route to the end of the tunnel is via the tunnel itself...

Right, nail up a /32 static route for the remote gre tunnel endpoint on 
each side. That /32 is nailed up to the next hop that you want the gre tunnel 
to always traverse. If that next hop becomes unavailable, the tunnel will 
go down, which is what you want rather than the tunnel trying to come up 
across some other path it can find.

> I use it too: but because I have no other choice.
> ----- Original Message -----
> From: "Robert Johnson" <fasterfourier at>
> To: "C. Jon Larsen" <jlarsen at>, nanog at
> Sent: Saturday, 29 January, 2011 6:48:50 PM
> Subject: Re: Need provider suggestions - BGP transit over GRE tunnel
> My network spans a multicity geographic area using microwave radio
> links. The point of the GRE tunnel is to allow me to establish a BGP
> session to another AS using a consumer grade Internet connection
> (cheap) over the public Internet. I don't want to build out additional
> microwave paths to a new datacenter to become multihomed.
> On Fri, Jan 28, 2011 at 5:36 PM, C. Jon Larsen <jlarsen at> wrote:
>> I have read your email a few times and i dont see how this makes sense.
>> Why do you need a public AS and PI space? Your gre tunnel wont need it or be
>> able to use it. A gre tunnel is just a replacement for a physical pipe.
>> If your datacenter based presence goes down, you will need a pipe at your
>> office, or some other location speaking bgp that can annouce your block
>> anyway.
> -- 
> This message has been scanned for viruses and
> dangerous content by the MailScanner, and is
> believed to be clean.

More information about the NANOG mailing list