Re: your mail

["Jon (Taz) Mischo" <taz@tazlore.com>]

On Wed, 18 Jul 2001, Ramakrishna Gummadi wrote:

> On Wed, 18 Jul 2001, Jon (Taz) Mischo wrote:
> 
> > Yes you are.  You are asking a provider to take all traffic destined for a
> > specific egress point and re-route it through their network to a peering
> > point.  You are *DOUBLING* the traffic they are carrying for that
> > subscriber.
> 
> I am sorry, but I may be missing something here---true, the traffic is
> doubled, but how to deal with the doubled traffic should be a decision
> between the provider and the subscriber according to the SLA. Increased
> load could cause higher packet loss, greater latency, etc. Indeed, if the
> provider were using fair queuing, this would what happen, without
> affecting any other customers of the provider. 

The last sentence is what's wrong.  A single router does not a backbone
make.  You seem to forget that a tunnel is not a wormhole.  Packets don't
enter a tunnel in one router and magically appear at the other end.  The
still traverse the network, following a different path than the one they
would normally, messing up a LOT.

> Like I said before, how is this case different than the one where the
> subscriber cancels the service from the other provider, due to which the
> load on the first provider would be increased anyway? Remember that we
> are not even requiring the first provider to participate in the tunnel
> setup...

Because you're completely munging up the ultilization.  There are suddenly
many megabits of traffic where there was none before.  I'd say that's
pretty different.

> > This isn't based on political reasons, but feasibility reasons, and we
> > don't outlaw, we just decide what we predict will be best.
> 
> Well, there is an easy, although socially questionable, answer to
> that---use IPSec on the tunnel so that the provider can not find out
> anything about the payload...

I fail to see how IPsec is going to get you around the problem.  The
problem isn't, "Oh, I see that's tunnelled data, I'll drop it!"  It is, "I
see that packet is coming from someone I don't peer with.  I'll drop it."

The main problem here is that some providers won't peer with others.  I
can guarantee that those same two providers won't configure their routers
to automatically build tunnels to each other.

> Once again, I don't see how doing this, while suboptimal and probably
> unfair, is going to violate the contract between the provider and the
> subscriber. All the provider would see is a surge in the traffic for the
> subscriber, and he will probably use the usual tools (fair queuing,
> increased latency and drop rate, etc. ) to deal with them...

Hello!  The provider will see a surge along his entire network!  This
isn't the magic schoolbus full of 0 length packets.  It's someone's OC-3
at full capacity being re-routed through other peoples' networks.  There's
a LOT more impact than you think.

-Taz

-- 
        "Be liberal in what you accept,
      and conservative in what you send."
--Jon Postel (1943-1998) RFC 1122, October 1989