Subject: [RRG] Charging for updates in BGP

From: Robin Whittle <[email-masked]>
Date: Fri, 26 Sep 2008 18:33:25 +1000

Hi Michael,

Continuing from:

  Re: [RRG] Separation vs. Elimination
  http://psg.com/lists/rrg/2008/msg02583.html

we were discussing charging for BGP updates, as part of discussing
similarities and differences between Ivip and BGP.

>> In both cases, there is a global system which enables packets
>> addressed to some prefix to be sent to some router.  Ivip only works
>> as an addition to the BGP system.  BGP works on its own.  BGP's
>> handling of changes is slow and expensive - and difficult or
>> impossible to charge end-users for when they make a change.  Ivip's
>
> Why? Say I'm your customer, and we have a configured BGP session. You
> count the number of updates that arrive over that connection per month,
> and then charge me per update once a month.

OK, I am an ISP and you are an edge network with your own PI space, generating
changed advertisements for whatever reasons, such as multihoming service
restoration and/or incoming traffic TE.  I assume you have one or more other
ISPs as well.

I could charge you per update, but it would probably only make business sense if
all the other ISPs did the same, at the same rate.  If they didn't charge, or
charged less, I would be at a competitive disadvantage.

Why would I want to do this, unless I was forced to do so by my upstream providers?

Why would they want to force me to do this, when I could choose some other
upstream provider which didn't force me to do so too?

Let's say I am ISP-1 and you multihome with ISP-2.  If ISP-1 and ISP-2 have very
different connections to the rest of the Net, when you change your advertisement
from one to the other, the effects may ripple through and cause messages to, and
changes of best path in, potentially every router in the DFZ.

If ISP-1 and ISP-2 share the same single upstream provider, or perhaps the same
two upstream providers . . . then no matter how often you change the way you
advertise your prefix with ISP-1 and ISP-2, you are probably only burdening
these two ISPs and a few routers at the edge of the common upstream provider(s).

So there is a wide variability in the impact of your update, depending on the
structure of the interdomain connections and how the routers are configured.  In
that case, how fair is it to charge you the same fee per update, when the impact
it has on the rest of the DFZ depends on things which are largely outside your
control?

I figure charging for each BGP changed advertisement could be done, like this,
via some technical and commercial arrangements.  However, it would only make a
marginal impact on the routing scaling problem.  Another arrangement might be to
have some global registry of ASes and their PI prefixes - where the ASes have
all agreed to pay some fee per update, to some central fund, and there is some
technical arrangement to monitor the changes they make, so the payments can be
seen to be correct.  But how would that work?  Some changes might not be
detectable except very close to the upstream ISPs of each edge network.

  - Robin

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From: Michael Meisel <[email-masked]>
Date: Sun, 28 Sep 2008 14:45:24 -0700

Hi Robin,

> detectable except very close to the upstream ISPs of each edge network.

I believe you have made my point for me -- this is technically feasible
with BGP, but probably not economically feasible.

As I understand it, you argue that a similar payment system *will* be
economically feasible under Ivip. It seems you claim this only because
Ivip is designed from the ground up to require this. But then it seems
to me that, if an ISP would say no to the question: "should I charge my
customers when they change their reachability in BGP?", then they would
also say no to the question: "should I deploy a system (Ivip) that
requires me to charge my customers when they change their reachability?"

-Michael

---

From: Geoff Huston <[email-masked]>
Date: Mon, 29 Sep 2008 09:57:26 +1000

> detectable except very close to the upstream ISPs of each edge  

http://www.potaroo.net/drafts/old/draft-bert-kyoto-protocol-00.html

Geoff

:-)

---

From: Robin Whittle <[email-masked]>
Date: Mon, 29 Sep 2008 10:34:11 +1000

Hi Michael,

> with BGP, but probably not economically feasible.

I would say that while it is technically feasible for anyone who
runs a DFZ router to charge the operators of neighbouring routers
for every update they make, that it is difficult to imagine this
being deployed widely enough to curtail whatever might be judged as
excessive updates by some edge networks.

I described some barriers to this charging idea being feasible in a
business sense, and no-doubt there are other barriers I didn't
anticipate.  Geoff Huston's sterling efforts in this field indicate
that the business arrangements would indeed be tortuous:
  http://www.potaroo.net/drafts/old/draft-bert-kyoto-protocol-00.html
http://unfccc.int/essential_background/kyoto_protocol/items/1678.php

Also, even if this happened, it would make only a marginal
difference to the routing scaling problem - we need a way of
providing provider independent addresses to millions of networks,
which is not made possible simply by reducing "excessive" update
rates.

> Ivip is designed from the ground up to require this. 

I haven't tried to list every reason why I think Ivip can and should
work this way.  This discussion is a good way of exploring these
matters.  I will take it up in another thread.

 - Robin