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@gmail.com> To: "Laird Popkin" <laird@pando.com> Cc: "Alexander Harrowell" <a.harrowell@gmail.com>, "Doug Pasko" <doug.pasko@verizon.com>, nanog@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@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@gmail.com> wrote:
On Wed, Apr 23, 2008 at 3:47 PM, Christopher Morrow <christopher.morrow@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 _______________________________________________ NANOG mailing list NANOG@nanog.org http://mailman.nanog.org/mailman/listinfo/nanog