Subject: RE: [P2Prg] Peer-to-Peer Internetworking

From: "Ayyasamy, Senthilkumar \(UMKC-Student\)" <[email-masked]>
Date: Sat, 23 Aug 2003 00:26:16 -0500

>Do you really believe this? 
[...]
>The below reminds me of most the the attempts to create protocol 
>translating gateways. They have never led to anything long lived, and 
>rarely is there a 1-1 mapping. Something is always lost.

 So, do you believe that a single underlay is going to serve all 
purpose? A number of technologies which tried doing everything
ended up with no wide acceptance( e.g.. ATM - A Total Mess) 
Lets just accept the fact that heterogeneity is present at all 
angles. A lot of islands exist within IP itself (IPv4, Ipv6,
site-locals). Also, the local private networks sometimes seems 
to be cellular networks (gprs etc), ad-hoc ( with 802.11.);wireless
networks need IP for remote connectivity. Then, we have developing 
technologies like sensors and fiber-channels (Storage area networks).
Also, we need PSTN-IP interworking for voice. 

  A single business model cannot satisfy the constraints of 
all the network types.  Hence, my own opinion is, we can 
either create primitives which help the interaction between
various islands ( e.g, jxta, Michel's FLAPPS can be extended
for such functions.) Else, specific inter-working (IWE) can
be done between domains(like IPNL- NAT extended architecture, 
Cheriton's content routing, MANET and IP IWEing.) For IP 
specific IWE, NATs and DNS are the possible extension victims.

 Imagine, a single universal identifiers for entities present
in different domains (IP, sensor, SAN etc.) Is that seems a
practical idea? How persistent those IDs will be... We are 
stuck at naming level itself; a single routing and addressing 
proposal seems not practical.

>> Since no single peer-to-peer network can serve universal purposes, 
>> functional decomposition among multiple peer-to-peer networks has 
>> to occur as peer-to-peer internetworking framework is defined.

 This seems to be IWE at the application level. It is nothing new; as  
application folks has invested a lot into work-flow service composition. 
So, just replace "peer-to-peer network" with "application service"; you 
can find a lot of vintage research works and even start ups. As major
market forces has started investing into web services, application 
interworking and automated service composition is very essential.

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From: Sean Bennett <[email-masked]>
Date: Sat, 23 Aug 2003 09:17:13 +0100

> ended up with no wide acceptance( e.g.. ATM - A Total Mess) 

Not to pick nits but ATM was bodged because the Telcos wanted very
different functionality from that what the computer industry required.

The reason that mattered is that at the time all the chip foundries refused
to fab masks (and hence chips) for a non-agreed standard.

So we got the mutant that is ATM. Nowa days we tend not to see ATM networks
because it just is pants for LAN work.

But look at your (A)DSL modem - odds are good it is talking ATM-25 running
Ethernet on-top of that. (well in the UK for sure)

So I completely agree that ATM is a bodge - but that it is for a variety of
reasons :)

> site-locals).

But surely that is because IP has few _policy_ based constraints?
i.e. the islands are created because the protocol lacks that capacity?

(and when one transitions from one protocol to another 4->6 one must create
islands)

> Also, the local private networks sometimes seems 

All of these talk common protocols at various points in the stack - after all
you don't really care how the packet is delivered - this is the nature of
an internetwork.

> all the network types. 

But Why should it?

Surley any bushiness model is about providing a service or a product in a way
that people will wish to pay for.

After all an IETF blessed P2P system that all computers in the world connect to
as they start up - or open a browser etc. has no 'value'.

Selling access to the global P2P system would have value.

Providing chargeable content would have value. So would approved indexing and
authoritative checking services. (i.e. 'The FT says this document is accurate - that will be 0.05 pence please')

I think that you are still thinking in terms of Napster/kaza bushiness models.

If I understand correctly the goal of this group is to render such systems
valueless and allow the construction of the next generation  - the Amazons, the
WalMarts, etc.

> proposal seems not practical.

A P2P system would involve the distribution of data. Otherwise a physical
object (this disk here) could not be distributed. Likewise with any physical
object. A Peer - to - Peer system is asymmetric when one Peer has significantly
different resources to other nodes.

Consider this (highly contrived) example:

My home computer has an outside temperature sensor.

As a public service I load the read out of that sensor into the P2P network.
The data holds who I am, the time of the reading, the location, the reading itself and it may included various references to how trustworthy I am - the
Met Office (the UK weather service) etc.

Whereas only my computer can load my copy of the temperature there is no
requirement to identify the sensor to the P2P network. In fact I could not
reference who I am at all. And be the 'reliable Cambridge weather station'
relying on my references from trusted 3rd parties.

I agree completely that a name space problem exists I would contend that
it lies in how to manage the data in any P2P network that is created rather
than in devices and sensors attached to it.

	Yours, Sean

-- 
Sean Bennett.
E Pluribus Unum

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From: Bill Yeager <[email-masked]>
Date: Sat, 23 Aug 2003 22:18:45 -0700

I do think that a single overlay can serve all. And, I am not being 
naive. The point of an overlay is that it hides the bearer networks, 
ie, is bearer network neutral. The underlying software that supports 
the overlay has the smarts to deal with any bearer network, and in a 
sense mediates bearer network differences.

Unfortunately, here I contradict myself a little. I know of translating 
peer rendezvous between bluetooth and TCP/IP, and they are very close 
to being able to merge a bluetooth network with the Internet on Jxta. 
The BT peers don't even know they are peers.

Also, there are already many examples that traverse 802.11a/b/g, 
cellular networks, satellite networks, ATM, sensor networks, mobile 
robots, etc ... using something as simple as the Jxta universal UUIDs. 
I don't believe these ID's are sufficient, and think a better routing 
model is needed if on has an Internet P2P network.

Lots of work needs to go into rdvs to make this happen, and in some 
case, as I say, protocol translation is necessary. The IP.v4/V6 problem 
is easily handled by the way.

There will also be ways to parition the overlay network into 
collections of peerNodes that wish to be virtual islands onto 
themselves within the overlay. Jxta calls these peerGroups. I call them 
connected communities.

I really envision a time when IP.v6 addresses can be used as UUIDs on 
such an overlay. That is a few years away, but I like to target a 
future where there is UUID consistency. There will always be rough 
edges but we should target smoothing these edges and encourage an 
evolution to a pretty much P2P Internet that makes life a lot easier 
for all of us who want to write applications across this space.

Bill

On Friday, August 22, 2003, at 10:26 PM, Ayyasamy, Senthilkumar

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From: Miles Sabin <[email-masked]>
Date: Sun, 24 Aug 2003 20:28:12 +0100

Bill Yeager wrote,
> sense mediates bearer network differences.

I think this is confusing two quite distinct kinds of heterogeneity: of 
the substrate networks; and of the overlay networks themselves.

Eliminating the first kind of heterogeneity is a non-starter. It's 
unreasonable to expect every peer to be able to deal with _any_ 
possible subtrate network ... lightweight peers for constrained devices 
should only have to be able to cope with the substrates they care about 
(eg. your Bluetooth example).

I also think that trying to eliminate the second kind of heterogeneity 
from the outset would be unwise. It would imply that we believe that 
one size fits all ... and that's _far_ from clear right now.

Your nod in the direction of JXTA PeerGroups is reasonable, but there's 
a fundamental difference between on the one hand starting from a single 
unifying network and slicing downwards to obtain scoping, and on the 
other starting from multiple, possibly application-specific networks 
and bridging. While I see the merits of the top-down approach, I also 
see the costs: reaching agreement on a single overarching model is 
likely to be painful and long-winded and unlikely to result in anything 
particularly palatable unless it's scope is so severely limited that it 
doesn't address issues much beyond those of, eg. IP. Which means that 
we'd be setting up a future WG either for interminable wrangling over 
something elaborate, or the redundancy of trying to produce yet another 
protocol of the same order as IP/TCP/HTTP to sit alongside all the 
others.

I think that starting with an enumeration of more abstract services that 
peers might call on is a more useful starting point than preempting a 
future WG by arguing the pros and cons of particular styles of overlay. 
If nothing else, it'll probably turn out that different types of 
service have very different requirements of an overlay, so leaving the 
possiblity of multiple service-specific overlays (perhaps with nothing 
much in common apart from the fact that they sit on top of the same 
substrate(s)) seems like a good option.

Cheers,

Miles

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From: Michael Rogers <[email-masked]>
Date: Mon, 25 Aug 2003 01:14:21 +0100 (BST)

> possible subtrate network

I don't think anyone's suggesting that - the idea is to provide a uniform
interface on top of every substrate, not a single implementation that works
on any substrate.

> ... lightweight peers for constrained devices 

I agree. But IDs should nevertheless be substrate-independent so that, eg
Bluetooth peers can talk to 802.11 peers via a suitable gateway, without
either end needing to know what substrate the other is using.

> reaching agreement on a single overarching model is 
> doesn't address issues much beyond those of, eg. IP.

What's wrong with that? I think it would be very useful to have "an IP for
peer-to-peer": ie, an unreliable datagram protocol which did not require
centralized management of the address space or central trusted authorities
for authentication.

That's why I believe IDs for any "p2p internet" should be self-certifying, eg
cryptographic hashes of public keys. The disadvantage of course is that
cryptographic hashes don't contain any location information, so the network
would also need a name service mapping IDs to (signed) location information.

Michael

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