[c-nsp] BGP peer/customer routes

[Peter Rathlev]

On Wed, 2011-06-01 at 09:18 +0200, Gert Doering wrote:
> If the customer is really creative, they announce the more specifics via
> the peering link *only* (but not to "the world").  So all the traffic is
> attracted by the aggregate from your upstreams into your AS, and there the 
> packets get redirected by the more-specifics to the peering links.
> 
> So you pay for your upstreams, and your peer gets the money from the 
> customer...

I can see why this specifically should not be allowed. :-)

But I'm thinking there are several reasons for a customer to deaggregate
and create a scenario indistinguishable from this without talking to the
customer.

> > What if I have a primary connection from AS11 and buy a backup
> > connection (much lower bandwidth) from you, but another of your
> > customers is the new Youtube? If you insist on sending traffic from them
> > down the backup pipe I bought from you it wouldn't work. 
> 
> Different issue.  If it's "just the backup" (e.g. "use community to set
> local-pref 70"), it won't be propagated world wide, and won't attract
> costly upstream traffic.

In that case the ISP would prefer the peer link, which I assume have
higher local preference. Or am I missing something? The result would be
the same (traffic wise) as if the customer deaggregated towards the
other ISP, i.e. OP scenario.

If ISP #1 somehow does not prefer the peer route (where the traffic
would end up at a 100 Mbit/s circuit I have with the peer) and instead
insists on sending it towards the 4 Mbit/s backup circuit I have with
the ISP #1 then I as a customer would be in trouble if other customers
of ISP #1 are ones I ask for a lot of traffic from.

-- 
Peter