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Re: IPv6 news

  • From: David Meyer
  • Date: Mon Oct 17 10:59:24 2005

On Sun, Oct 16, 2005 at 01:45:40AM -0700, Tony Li wrote:
> >
> >Doesn't NAT, or more specifically the most commonly used, NAPT, create
> >hard state within the network, which then makes it violate the
> >end-to-end argument ? Also, because it has to understand transport and
> >application layer protocols, to be able to translate embedded  
> >addresses,
> >doesn't this also make it violate end-to-end ? I've understood the
> >fundamental benefit of following the end-to-end argument is that  
> >you end
> >up with a application agnostic network, which therefore doesn't create
> >future constraints on which applications can then be used over that
> >network. In an end-to-end "compliant" network, any new transport layer
> >protocols, such as SCTP or DCCP, and new user applications, only  
> >require
> >an upgrade of the end or edge node software, which can be performed in
> >an incremental, per edge node as needed basis. In other words, there
> >isn't any whole of network upgrade cost or functionality deployment
> >delay to support new applications, which was the drawback of  
> >application
> >specific networks, such as the traditional POTS network.
> >
> >Have I somehow misunderstood the intent or benefits of the end-to-end
> >argument ?
> Mark,
> This is probably the most common misunderstanding of the end-to-end  
> principle out there.  Someone else can dig up the quote, but  
> basically, the principle says that the network should not replicate  
> functionality that the hosts already have to perform.  You have to  
> look at X.25's hop-by-hop data windows to truly grok this point.
> Many people pick this up and twist it into ~the network has to be  
> application agnostic~ and then use this against NATs or firewalls,  
> which is simply a misuse of the principle.  Really, this is a  
> separate principle in and of its own right.  It's not one that I  
> subscribe to, but that's a different conversation...

	Maybe its time to pull out some of Noel's work on both
	topics. Reasonable introductions to both the e2e
	principle and locator/id split topics can be found on and



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