Subject: [p2p-sip] Problem statement for P2P SIP NAT traversal

From: slavitch at objectworld.com (Michael Slavitch)
Date: Wed, 8 Mar 2006 10:38:20 -0500

Juergen, good feedback. Thank you.

Comments inline. Apologies in advance for any misquotes.

Juergen:  

>I just wanted to state that whatever we develop, it should be possible
to implement it for an IPv4 environment as well as >for an IPv6
environment (probably in different ways).  This does not imply that
every implementation must fully support both (which would not make too
much sense).

Me:

I agree. But we have the power to make supporting 'any' underlying
transport transparent.

>Still, we can think about whether or not, an IPv6 client needs to be
become aware that its public IP address is an IPv4 
>address (or vice versa). The current SIP/SDP specification would
require this.

Me:  

If you force a UA to use numeric addressing that is true. IF a UA can
use name-based addressing it is different.
This may require subtle changes to the SIP/SDP specifications. If that
name can be abstracted the world opens up.
Note that the name could be a numeric address, a DNS address, or some
kind of overloaded address. Once the addressing is abstract so is the
underlying transport. This is the essence of a possible solution. 

(my original email):
>> exist in the mesh, but it must not be the defining characteristics of

>> the mesh itself, otherwise we are limiting ourselves once again to 
>> orthodoxy.  There are several well-known techniques already discussed

>> in this list that makes the underlying addressing protocols abstract 
>> entitites.  They work both in theory

Juergen:

>This is a nice way of dealing with the IPv4/IPv6 problem that certainly
should be considered as design choice for our P2P 
>SIP solution.

I agree. I'm also very glad that other people have already done most of
the work. :%)

> and in practise, are well-founded, and should be considered. They are 
> not open research topics, they are new elaborations of well-understood

> techniques.  The only matter left is determining if the underlying 
> abstraction identifiers are robust enough and can map into SIP without

> any changes or harm.
>
> P2P overlays can traverse any protocol that has the following
characteristics:
>
> 1. A known consistant datalink layer.
> 2. A known consistant socket mechanism.
> 3. An addressing scheme that can be overloaded by some well-published 
> or well-known identifier.
>
> That's it.

>>Right ... except for setting it up. when you bootstrap the overlay or
connect a new node, you might have to care about >>the ugly NATted world
underneath.

Michael (my key comment):  

Not if the bootstrapping is done out of band. Each device we use can
fetch things out of band with different protocols.
OOB can mean anything, from a slip of paper with a code in it to an
http:// url, to an SMS message, or anything.

Done well bootstrapping can be done by carrier pigeon. It doesn't have
to be fancy or elegant. Elegance may be a bad idea.
It should however be simple and flexible.

For example, a whole system can be simultaneously bootstrapped by an
email sent to a list. It's ugly, but it is good. 
In existing rugged implementations multiple modes of bootstrapping are a
requirement in case the standard method is quite literally blown up out
of existence. In that case responsibility must be delegated to secondary
methods, no matter how inelegant or distasteful.

M

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---

From: quittek at netlab.nec.de (Juergen Quittek)
Date: Wed, 08 Mar 2006 16:59:19 +0100

Michael,

I like your view.  We have implemented this concept already
and are promoting it.  But currently, we limit promotion to
research projects.  I am not sure, this technology is already
mature enough for standardization at the IETF.  Let's see.

And let's see what the (future) working group thinks about it.

Thanks,

    Juergen

--On 3/8/06 10:38 AM -0500 Michael Slavitch wrote:

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---

From: henry at pulver.com (Henry Sinnreich)
Date: Wed, 8 Mar 2006 11:04:28 -0600

> I am not sure, this technology is already mature enough for 
> standardization at the IETF.

About 80% of the Internet traffic is P2P and it does NAT traversal. 
This should be good enough.

Thanks, Henry

-----Original Message-----
From: p2p-sip-bounces at cs.columbia.edu
[mailto:p2p-sip-bounces at cs.columbia.edu] On Behalf Of Juergen Quittek
Sent: Wednesday, March 08, 2006 9:59 AM
To: Michael Slavitch; Michael Slavitch; P2P-SIP
Subject: Re: [p2p-sip] Problem statement for P2P SIP NAT traversal

Michael,

Thanks,

    Juergen

---

From: quittek at netlab.nec.de (Juergen Quittek)
Date: Wed, 08 Mar 2006 18:37:29 +0100

Henry,

> This should be good enough.

But 95% or more of this P2P traffic deals with concrete IP(v4)
addresses and is a little bit more down to earth compared to
Michael's view when it solves the NAT traversal problem.
This could be good enough.

Thanks,

    Juergen