Peering + Transit Circuits

Wed Aug 19 00:30:45 UTC 2015

On Tue, Aug 18, 2015 at 11:27:53PM +0000, Faisal Imtiaz wrote:
> Thanks for the explanation, 
> I am still trying to figure out the realistic business case where
> doing something like this would make sense to any party. 
> (unless purely malicious or in error). 

I'm sure others will reply as well, but in case it helps someone
googling in years to come...

Let's look at ParasiteNet, a content heavy network with three BGP
peerings:
  - Transit provider A via 100Mbps
  - Transit provider B via 100Mbps
  - Peer P via 1GBps (who also buys from provider B at 10G)

If ParasiteNet needed to push more than 100Mbps to provider B, they
might be tempted to route the traffic to peer P, even though peer P
didn't advertise those routes.

ParasiteNet gets a free ride if peer P doesn't notice what is going on
(until they need more than 100Mbps inbound).

I've been told of an occurance of this when a private network started
peering with an edu network.  Once the link was up, an absurd amount of
traffic went across the link -- all destined for "the Internet" rather
than the edu network.

When the edu network shutdown the link, they were threatened with
lawsuits...