[c-nsp] BGP ip addresses re-route to specific link

[Ivan Pepelnjak]

Inbound traffic: advertise /28 to upstream2. It will not get very far, though, so it's questionable whether it will leak over to upstream1 and influence the return traffic coming from upstream1.

Outbound traffic: policy routing seems to be the quickest (and the dirtiest ;) solution. Getting it to work if the exit points are too far apart is a nightmare. If you're OK with the /28 being very tightly bound to the specific uplink (i.e. no connectivity when the uplink is down), there are a few MPLS VPN tricks you could use.

Ivan

> -----Original Message-----
> From: Dracul [mailto:chris.garzon at gmail.com]
> Sent: Tuesday, January 05, 2010 5:17 PM
> To: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] BGP ip addresses re-route to specific link
> 
> > you can use "BGP Conditional Route Injection" to generate the /28. (it
> shud be a child subnet out of the parent /24). then filter the prefixes so
> select which all upstreams shud receive this injected
> > subnet.
> 
> thanks swap will explore your suggestion.
> 
> 
> >Be aware that many (most) ISPs would filter subnets longer than /24, so
> >your /28 would be most likely filtered (even if you direct upstream
> >would send it through).
> >Arie
> 
> Thanks arie, will keep it in mind.
> 
> On Tue, Jan 5, 2010 at 5:00 PM, Ivan Pepelnjak <ip at ioshints.info> wrote:
> 
> > Are you trying to do destination-based routing (packet TO specific
> address
> > should go over specific link) or source-based routing (packet FROM
> specific
> > /28 should go over specific upstream link)?
> >
> >
> Hi Ivan, I guess both. i just want to have a specific ip block traffic
> contained to a specific link ( the ip addresses are broadcast under BGP)
> 
> regards,
> Chris
> 
> > -----Original Message-----
> > > From: Dracul [mailto:chris.garzon at gmail.com]
> > > Sent: Tuesday, January 05, 2010 8:05 AM
> > > To: cisco-nsp at puck.nether.net
> > > Subject: [c-nsp] BGP ip addresses re-route to specific link
> > >
> > > Hi there,
> > >
> > > I was wondering if you could do a segregate route, for specfic ip
> > > addresses
> > > under BGP going only to a specific link.
> > > for example if I have /24 default route BGP pool and I want only /28
> ip
> > > addresses using upstream1 and not by any
> > > account go through upstream2. The rest would still be using the usual
> BGP
> > > routing behavior. THanks!
> > >
> > > regards,
> > > Chris
> >
> >
> >