[85784] in North American Network Operators' Group
Re: IPv6 news
daemon@ATHENA.MIT.EDU (David Meyer)
Mon Oct 17 10:58:34 2005
Date: Mon, 17 Oct 2005 07:57:52 -0700
From: David Meyer <dmm@1-4-5.net>
To: Tony Li <tony.li@tony.li>
Cc: Mark Smith <random@72616e646f6d20323030342d30342d31360a.nosense.org>,
drc@virtualized.org, vixie@vix.com, nanog@merit.edu
In-Reply-To: <67815ABA-9B06-4F88-ABFD-C7559AC0F617@tony.li>
Errors-To: owner-nanog@merit.edu
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On Sun, Oct 16, 2005 at 01:45:40AM -0700, Tony Li wrote:
>=20
> >
> >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 =20
> >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 =20
> >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 =20
> >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 =20
> >application
> >specific networks, such as the traditional POTS network.
> >
> >Have I somehow misunderstood the intent or benefits of the end-to-end
> >argument ?
>=20
>=20
> Mark,
>=20
> This is probably the most common misunderstanding of the end-to-end =20
> principle out there. Someone else can dig up the quote, but =20
> basically, the principle says that the network should not replicate =20
> functionality that the hosts already have to perform. You have to =20
> look at X.25's hop-by-hop data windows to truly grok this point.
>=20
> Many people pick this up and twist it into ~the network has to be =20
> application agnostic~ and then use this against NATs or firewalls, =20
> which is simply a misuse of the principle. Really, this is a =20
> separate principle in and of its own right. It's not one that I =20
> 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=20
http://users.exis.net/~jnc/tech/end_end.html and
http://users.exis.net/~jnc/tech/endpoints.txt
respectively.=20
Dave
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