[p2p-hackers] Final version of "P2P over NAT" paper available

Alex Pankratov ap at hamachi.cc
Sun Feb 20 00:26:28 UTC 2005



David Barrett wrote:

> I'm sorry, I didn't make my question clear.  Given that you can hole 
> punch for 82-97% of NAT'd users, how many users are behind NATs in the
> first place?

Around 70%, but keep in mind that 16000+ samples we have at the moment
are far from being representative.

> 
> For example if only 1% of users is behind a NAT then hole punching 
> doesn't much matter.  But it's 25%, 50%, or 75%, it becomes critical.
> 
> Does this question make sense?

Yes, let me clarify the numbers I gave earlier -

82% is ratio of 'identity preserving' NATs among all NAT'ed clients
we saw. 97% - is a number of user pairs (including routable clients)
that we were able to successfully connect. If we were only to use
technique suggested in p2pnat paper, 97% would've become 84%.

> 
> Likewise, I'm interested in a similar stat for firewalls.

The stats for firewall that allow outbound UDP is 100%, ie you can
always connect two peers behind two separate _stateful_ firewalls
that allow unrestricted outbound UDP. The % of those behind locked-
down firewalls is neglible as well as the % of those behind the
same firewall that doesn't allow for hairpin'ing.

> 
> Sorry for not being clear the first time.

Not a problem.

> 
> -david
> 
> On Sat, 19 Feb 2005 12:32 pm, Alex Pankratov wrote:
> 
>> Well, based on same stats it looks like 'hole punching' as it's
>> described in p2pnat paper succeeds in ~84% of the cases. Our
>> proggy is a bit more complex than that so our success rate is
>> about 97%.
>>
>> Alex
>>
>> David Barrett wrote:
>>
>>> Heh, great validation of the results.
>>> So if what's the latest values for the following chart:
>>>                         NAT'd     Firewalled
>>>                      +---------+-------------
>>> % Able to hole punch |  82.2%  |   50-60% *
>>> % of total internet  |   ??    |     ??
>>>                      +---------+-------------
>>> % Benefiting         |   ??    |     ??
>>> * http://zgp.org/pipermail/p2p-hackers/2004-December/002215.html
>>> Basically, I'd like to get a better understanding of what fraction of 
>>> all
>>> internet users might benefit from these techniques, estimated as the 
>>> product
>>> of the above rows.
>>> -david
>>>
>>>> -----Original Message-----
>>>> From: p2p-hackers-bounces at zgp.org 
>>>> [mailto:p2p-hackers-bounces at zgp.org] On
>>>> Behalf Of Alex Pankratov
>>>> Sent: Friday, February 18, 2005 11:04 PM
>>>> To: Peer-to-peer development.
>>>> Subject: Re: [p2p-hackers] Final version of "P2P over NAT" paper 
>>>> available
>>>>
>>>> Bryan,
>>>>
>>>> Quoting your paper -
>>>>
>>>>>  .. we find that about 82% of the NATs tested support hole punching
>>>>>  for UDP.
>>>>>  ..
>>>>
>>>>
>>>>> The NAT Check data we gathered consists of 380 reported data points
>>>>
>>>>
>>>>>  ..
>>>>
>>>>
>>>> I happened to have statistics for more than 16000 'data poits', and
>>>> check this out - the rate of 'identity preserving' NAT devices suitable
>>>> for hole punching works out to be 82.2%. *UDP* hole punching that is.
>>>>
>>>> Alex
>>>>
>>>> Bryan Ford wrote:
>>>>
>>>>
>>>>> Hi folks,
>>>>>
>>>>> For those interested in P2P-over-NAT issues, I just wanted to announce
>>>>
>>>>
>>>> that
>>>>
>>>>> the final version of the following paper, to appear in USENIX '05, is
>>>>
>>>>
>>>> now
>>>>
>>>>> available:
>>>>>
>>>>> Peer-to-Peer Communication Across Network Address Translators, Bryan
>>>>
>>>>
>>>> Ford,
>>>>
>>>>> Pyda Srisuresh, and Dan Kegel. USENIX Annual Technical Conference, 
>>>>> April
>>>>> 2005.
>>>>> (PDF) http://www.brynosaurus.com/pub/net/p2pnat.pdf
>>>>> (HTML) http://www.brynosaurus.com/pub/net/p2pnat/
>>>>>
>>>>> An earlier draft of this paper was announced on this list a few months
>>>>
>>>>
>>>> ago.
>>>>
>>>>> The final version includes, among other minor revisions, new "NAT 
>>>>> Check"
>>>>> testing results based on almost twice the number of data points as the
>>>>> original draft.
>>>>>
>>>>> Cheers,
>>>>> Bryan
>>>>>
>>>>> ---
>>>>>
>>>>> Abstract:
>>>>>
>>>>> Network Address Translation (NAT) causes well-known difficulties for
>>>>> peer-to-peer (P2P) communication, since the peers involved may not be
>>>>> reachable at any globally valid IP address. Several NAT traversal
>>>>
>>>>
>>>> techniques
>>>>
>>>>> are known, but their documentation is slim, and data about their
>>>>
>>>>
>>>> robustness
>>>>
>>>>> or relative merits is slimmer. This paper documents and analyzes 
>>>>> one of
>>>>
>>>>
>>>> the
>>>>
>>>>> simplest but most robust and practical NAT traversal techniques,
>>>>
>>>>
>>>> commonly
>>>>
>>>>> known as ``hole punching.'' Hole punching is moderately 
>>>>> well-understood
>>>>
>>>>
>>>> for
>>>>
>>>>> UDP communication, but we show how it can be reliably used to set up
>>>>> peer-to-peer TCP streams as well. After gathering data on the
>>>>
>>>>
>>>> reliability of
>>>>
>>>>> this technique on a wide variety of deployed NATs, we find that about
>>>>
>>>>
>>>> 82% of
>>>>
>>>>> the NATs tested support hole punching for UDP, and about 64% support
>>>>
>>>>
>>>> hole
>>>>
>>>>> punching for TCP streams. As NAT vendors become increasingly conscious
>>>>
>>>>
>>>> of the
>>>>
>>>>> needs of important P2P applications such as Voice over IP and online
>>>>
>>>>
>>>> gaming
>>>>
>>>>> protocols, support for hole punching is likely to increase in the
>>>>
>>>>
>>>> future.
>>>>
>>>>> _______________________________________________
>>>>> p2p-hackers mailing list
>>>>> p2p-hackers at zgp.org
>>>>> http://zgp.org/mailman/listinfo/p2p-hackers
>>>>> _______________________________________________
>>>>> Here is a web page listing P2P Conferences:
>>>>> http://www.neurogrid.net/twiki/bin/view/Main/PeerToPeerConferences
>>>>>
>>>>>
>>>>
>>>> _______________________________________________
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>>>> _______________________________________________
>>>> Here is a web page listing P2P Conferences:
>>>> http://www.neurogrid.net/twiki/bin/view/Main/PeerToPeerConferences
>>>
>>>
>>> _______________________________________________
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>>> http://zgp.org/mailman/listinfo/p2p-hackers
>>> _______________________________________________
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>>> http://www.neurogrid.net/twiki/bin/view/Main/PeerToPeerConferences
>>>
>> _______________________________________________
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>> http://zgp.org/mailman/listinfo/p2p-hackers
>> _______________________________________________
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>> http://www.neurogrid.net/twiki/bin/view/Main/PeerToPeerConferences
> 
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> p2p-hackers at zgp.org
> http://zgp.org/mailman/listinfo/p2p-hackers
> _______________________________________________
> Here is a web page listing P2P Conferences:
> http://www.neurogrid.net/twiki/bin/view/Main/PeerToPeerConferences
> 
> 



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