North American Network Operators Group

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RE: Can P2P applications learn to play fair on networks?

  • From: Frank Bulk
  • Date: Tue Oct 23 23:41:17 2007

My apologies if I wasn't clear -- my point was that caching toward the
client base changes installed architectures, an expensive proposition.  If
caching will find any success it needs to be at the lowest possible price
point, which means collocating where access and transport meet, not in the

I have little reason to believe that providers are going to cache for the
internet to solve their last-mile upstream challenges.


-----Original Message-----
From: Rich Groves [mailto:[email protected]] 
Sent: Monday, October 22, 2007 11:49 PM
To: [email protected]; [email protected]
Subject: Re: Can P2P applications learn to play fair on networks?


The problem caching solves in this situation is much less complex than what
you are speaking of. Caching toward your client base brings down your
transit costs (if you have any)........or lowers congestion in congested
areas if the solution is installed in the proper place. Caching toward the
rest of the world gives you a way to relieve stress on the upstream for

Now of course it is a bit outside of the box to think that providers would
want to cache not only for their internal customers but also users of the
open internet. But realistically that is what they are doing now with any of
these peer to peer overlay networks, they just aren't managing the boxes
that house the data. Getting it under control and off of problem areas of
the network should be the first (and not just future) solution.

There are both negative and positive methods of controlling this traffic.
We've seen the negative of course, perhaps the positive is to give the user
what they want ......just on the providers terms.

my 2 cents

From: "Frank Bulk" <[email protected]>
Sent: Monday, October 22, 2007 7:42 PM
To: "'Rich Groves'" <[email protected]>; <[email protected]>
Subject: RE: Can P2P applications learn to play fair on networks?

> I don't see how this Oversi caching solution will work with today's HFC
> deployments -- the demodulation happens in the CMTS, not in the field.
> And
> if we're talking about de-coupling the RF from the CMTS, which is what is
> happening with M-CMTSes
> (, you're really
> changing an MSO's architecture.  Not that I'm dissing it, as that may be
> what's necessary to deal with the upstream bandwidth constraint, but
> that's
> a future vision, not a current reality.
> Frank
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of
> Rich
> Groves
> Sent: Monday, October 22, 2007 3:06 PM
> To: [email protected]
> Subject: Re: Can P2P applications learn to play fair on networks?
> I'm a bit late to this conversation but I wanted to throw out a few bits
> of
> info not covered.
> A company called Oversi makes a very interesting solution for caching
> Torrent and some Kad based overlay networks as well all done through some
> cool strategically placed taps and prefetching. This way you could "cache
> out" at whatever rates you want and mark traffic how you wish as well.
> This
> does move a statistically significant amount of traffic off of the
> upstream
> and on a gigabit ethernet (or something) attached cache server solving
> large
> bits of the HFC problem. I am a fan of this method as it does not require
> a
> large foot print of inline devices rather a smaller footprint of statics
> gathering sniffers and caches distributed in places that make sense.
> Also the people at Bittorrent Inc have a cache discovery protocol so that
> their clients have the ability to find cache servers with their hashes on
> them .
> I am told these methods are in fact covered by the DMCA but remember I am
> no
> lawyer.
> Feel free to reply direct if you want contacts
> Rich
> --------------------------------------------------
> From: "Sean Donelan" <[email protected]>
> Sent: Sunday, October 21, 2007 12:24 AM
> To: <[email protected]>
> Subject: Can P2P applications learn to play fair on networks?
>> Much of the same content is available through NNTP, HTTP and P2P. The
>> content part gets a lot of attention and outrage, but network engineers
>> seem to be responding to something else.
>> If its not the content, why are network engineers at many university
>> networks, enterprise networks, public networks concerned about the impact
>> particular P2P protocols have on network operations?  If it was just a
>> single network, maybe they are evil.  But when many different networks
>> all start responding, then maybe something else is the problem.
>> The traditional assumption is that all end hosts and applications
>> cooperate and fairly share network resources.  NNTP is usually considered
>> a very well-behaved network protocol.  Big bandwidth, but sharing network
>> resources.  HTTP is a little less behaved, but still roughly seems to
>> share network resources equally with other users. P2P applications seem
>> to be extremely disruptive to other users of shared networks, and causes
>> problems for other "polite" network applications.
>> While it may seem trivial from an academic perspective to do some things,
>> for network engineers the tools are much more limited.
>> User/programmer/etc education doesn't seem to work well. Unless the
>> network enforces a behavor, the rules are often ignored. End users
>> generally can't change how their applications work today even if they
>> wanted too.
>> Putting something in-line across a national/international backbone is
>> extremely difficult.  Besides network engineers don't like additional
>> in-line devices, no matter how much the sales people claim its fail-safe.
>> Sampling is easier than monitoring a full network feed.  Using netflow
>> sampling or even a SPAN port sampling is good enough to detect major
>> issues.  For the same reason, asymetric sampling is easier than requiring
>> symetric (or synchronized) sampling.  But it also means there will be
>> a limit on the information available to make good and bad decisions.
>> Out-of-band detection limits what controls network engineers can
>> implement
>> on the traffic. USENET has a long history of generating third-party
>> cancel
>> messages. IPS systems and even "passive" taps have long used third-party
>> packets to respond to traffic. DNS servers been used to re-direct
>> subscribers to walled gardens. If applications responded to ICMP Source
>> Quench or other administrative network messages that may be better; but
>> they don't.