Subject: [P2Prg] Re: lightweight decentralized search / discovery

From: "Martin Peck" <[email-masked]>
Date: Thu, 10 Jul 2003 09:48:31 -0700

Andersen Frank-Uwe wrote:

>Hi,
>
>I am working in a think-tank like department of a mobile network
>manufacturer. Having worked on the design of e.g. "mobile portals",
>WAP systems and the like, I recognized the p2p "wave" for quite some
>time, but we couldn't figure out how this would affect mobile devices
>using, for example, third generation (or beyond) mobile systems.

Ad-hoc/mobile community wireless and peer networks are a pair of
complementary technologies that were made to go together.  I'd love to
hear more about the types of applications and features you anticipate
designing / implementing...

>One of the main obstacle is, in our point of view, the bandwidth
>consumption for search algorithms that occurs even for passive
>participants of most p2p networks. To be more precise: running
>today's p2p clients on mobile phones is just not feasible for
>several reasons (simple pricing is one of them).
>
>This is why we are most interested in modified search algorithms as
>well as bandwidth limited/optimized distributed storage systems for
>mobile peers.

A project I have been working on for a while may be of interest.  It is
called "alpine" and uses a unicast UDP discovery mechanism with peer
grouping and profiling to optimize keyword and arbitrary metadata based
discovery in a fully decentralized manner.

Specifically:
* Peer communication uses small UDP datagrams without any forwarding.
* NAT is assumed and public endpoint resolution supported in the
protocol.  This works perfectly for cone NAT's but suffers
inefficiencies when two symmetric NAT clients are communicating.  This
works well for mobile clients changing IP's and/or ports.
* A single level of indirection is supported so that remote peers
(wireless clients, clients on dial-up, etc) can utilize the search
capacity of a home computer on broadband or any other peer that may
grant them a "proxy" session.  In this case query packets are sent to a
single peer who then repeats the query using its own peer groups (and
only once, no multiple forwards).
* Bandwidth consumption in the UDP based application level network stack
is configurable by the user.

The "peer proxy" mode was designed specifically for this situation, where
a low bandwidth client wishes to legitimately utilize the resources of a
server or high bandwidth peer to perform discovery on its behalf.

I am having some hosting problems at the moment; a temporary cache of
some documentation is available here:
http://67.168.233.105:8080/alpine/overview.html
http://67.168.233.105:8080/alpine/discovery.html

802.11 wifi is my main wireless network target, although I am also
having fun with the J2ME toolkit on the motorola i88 iDEN phones
(Nextel) despite their comparatively constricted bandwidth.

A wifi client could support a full alpine stack, however, the 2.5G/3G
data services from the major wireless carriers are either slow enough
or expensive enough to warrant a lightweight client stack only (which
would use a full fledged peer node to perform discovery requests by
proxy)

>Hence, may we suggest to the group to bear in mind these special
>requirements for mobile systems for the upcoming work.

I would love to know more about the specific applications you intend to
use this discovery / search feature for.  What types of architectures
have you tried, and how were they insufficient?  (I.e. a DHT would allow
efficient lookup with very little bandwidth, but providing a flexible
metadata / keyword discovery on top of a DHT is proving difficult)

Best regards,
    Martin Peck.

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From: Lucas Gonze <[email-masked]>
Date: Sat, 19 Jul 2003 13:16:07 -0400

Sam Joseph has created a wiki (at 
http://www.neurogrid.net/twiki/bin/view/Main/PeerToPeerConferences) for 
tracking P2P conferences.  This needs to reach a certain amount of 
awareness and involvement to take off, and I want it to take off, so 
I'm posting here to request that folks chip in.

(Why do I want it to take off? Because I'm annoyed with the mismatch 
between moments when I have work ready to show and times when I find 
out about places to show it.  There's this half finished paper in my 
desk drawer waiting for a submission date to force me to finish it...)

I have added a notice about it to the standard footer for messages on 
the decentralization list.  The footer text I'm using is:
Announce or discover P2P conferences on the P2P Conference Wiki at
http://www.neurogrid.net/twiki/bin/view/Main/PeerToPeerConferences

Bill and Bobby, any chance you'd do something similar with 
[email-masked]?

Other good things to do would be to blog about it, to put it in your 
blogroll, or to put a link on any p2p-related sites or pages.

Thanks.

- Lucas Gonze

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From: Bill Yeager <[email-masked]>
Date: Sat, 19 Jul 2003 16:38:46 -0700

We'll see what we can do here. It's a good idea.

Also, sorry for the silence. Bobby and I are doing things in the 
background, and we will soon send a message reflecting these efforts. 
It is mostly about a kickoff meeting.

Bill