[Nanog] P2P traffic optimization Was: Lies, Damned Lies, and Statistics [Was: Re: ATT VP: Internet to hit capacity by 2010]

Laird Popkin laird at pando.com
Wed Apr 23 17:30:46 CDT 2008


I would certainly view the two strategies (reverse engineering network information and getting ISP-provided network information) as being complimentary. As you point out, for any ISP that doesn't provide network data, we're better off figuring out what we can to be smarter than 'random'. So while I prefer getting better data from ISP's, that's not holding us back from doing what we can without that data.

ISP's have been very clear that they regard their network maps as being proprietary for many good reasons. The approach that P4P takes is to have an intermediate server (which we call an iTracker) that processes the network maps and provides abstracted guidance (lists of IP prefixes and percentages) to the p2p networks that allows them to figure out which peers are near each other. The iTracker can be run by the ISP or by a trusted third party, as the ISP prefers.

- Laird Popkin, CTO, Pando Networks
  mobile: 646/465-0570

----- Original Message -----
From: "Christopher Morrow" <morrowc.lists at gmail.com>
To: "Laird Popkin" <laird at pando.com>
Cc: "Alexander Harrowell" <a.harrowell at gmail.com>, "Doug Pasko" <doug.pasko at verizon.com>, nanog at nanog.org
Sent: Wednesday, April 23, 2008 5:14:12 PM (GMT-0500) America/New_York
Subject: Re: P2P traffic optimization Was: [Nanog] Lies, Damned Lies, and Statistics [Was: Re: ATT VP: Internet to hit capacity by 2010]

On Wed, Apr 23, 2008 at 3:50 PM, Laird Popkin <laird at pando.com> wrote:
>
>  On Apr 23, 2008, at 2:17 PM, Christopher Morrow wrote:
>
> > On Wed, Apr 23, 2008 at 11:39 AM, Alexander Harrowell
> > <a.harrowell at gmail.com> wrote:
> >
> > >
> > >
> > >
> > > On Wed, Apr 23, 2008 at 3:47 PM, Christopher Morrow
> > > <christopher.morrow at gmail.com> wrote:
> > >
> > > >
> > > > It strikes me that often just doing a reverse lookup on the peer
> > > > address would be 'good enough' to keep things more 'local' in a
> > > > network sense. Something like:
> > > >
> > > > 1) prefer peers with PTR's like mine (perhaps get address from a
> > > > public-ish server - myipaddress.com/ipchicken.com/dshield.org)
> > > > 2) prefer peers within my /24->/16 ?
> > > >
> > > > This does depend on what you define as 'local' as well, 'stay off my
> > > > transit links' or 'stay off my last-mile' or 'stay off that godawful
> > > > expensive VZ link from CHI to NYC in my backhaul network...
> > > >
> > >
> > > Well. here's your problem; depending on the architecture, the IP
> addressing
> > > structure doesn't necessarily map to the network's cost structure. This
> is
> > > why I prefer the P4P/DillTorrent announcement model.
> > >
> > >
> >
> > sure 80/20 rule... less complexity in the clients and some benefit(s).
> > perhaps short term something like the above with longer term more
> > realtime info about locality.
> >
>
>  For the applications, it's a lot less work to use a clean network map from
> ISP's than it is to in effect derive one from lookups to ASN, /24, /16,
> pings, traceroutes, etc. The main reason to spend the effort to implement
> those tactics is that it's better than not doing anything. :-)
>

so.. 'not doing anything' may or may not be a good plan.. bittorrent
works fine today(tm). On the other hand, asking network folks to turn
over 'state secrets' (yes some folks, including doug's company)
believe that their network diagrams/designs/paths are  in some way
'secret' or a 'competitive advantage', so that will be a blocking
factor. While, doing simple/easy things initially (most bittorrent
things I've seen have <50 peers certainly there are more in some
cases, but average? > or < than 100? so dns lookups or bit-wise
comparisons seem cheap and easy) that get the progress going seems
like a grand plan.

Being blocked for the 100% solution and not making
progress/showing-benefit seems bad :(

-Chris




More information about the NANOG mailing list