Re: [arch-d] [Int-area] Is IPv6 End-to-End? R.I.P. Architecture? (Fwd: Errata #5933 for RFC8200)

[Joe Touch <touch@xxxxxxxxxxxxxx>]

 

On 2020-02-27 14:26, Phillip Hallam-Baker wrote:

On Thu, Feb 27, 2020 at 5:09 PM Tom Herbert <tom@xxxxxxxxxxxxxxx> wrote:

Fernando,

I think we need to be careful that IETF is labeled as a collection of
inflexible architectural purists. We know that standards conformance
is voluntary and we haven't seen the last time that someone, possibly
even a major vendor, will circumvent the system for their own
purposes.

 

IP end to end does not mean the IP address is constant end to end. It never has meant that and never will.

 

Actually, that's the only thing it ever meant and always will. When addresses change, *by definition*, the*ends* change (and yes, that's what NATs do - they create end-to-end CONTENT transfer over separate end-to-end Internets).

..

We discovered that there were good reasons for NATing IPv4 besides address multiplexing. The topology of my network is none of your business.

 

Agreed; there's nothing that forces you to use IP addresses in a way that exposes your topology (you're free to build a net using host routing). That has nothing to do with NAT.

 

I have not found a rationale for NATs that doesn't start and end with a business model where servers are charged business rates and clients are charged customer rates. Everything else about NATs either isn't a NAT property (hiding topology) or can be achieved by a stateful firewall (that predates NATs by a decade, e.g. that lets outgoing connections go through but not incoming).

 

More generally, Internet standards only apply to the Inter-net, the network of networks. What happens inside the networks at either end is for the owners of those networks to decide. If we go back to the original Internet design, they didn't even need to run IP. IP end to end come later.

 

That's true, but then their "end" on the public Internet would be the firewall or NAT box at their edge.

 

So let us stop being dogmatic about things that don't actually matter. The only job of the network layer is to get packets from one end to another. The only job of the transport layer is to provide reliable streams. An application protocol that depends on the IP address remaining constant end to end is a bad protocol and should be rejected.

 

That's a very OSI view of protocols - about as out-dated and about as useful., IMO. Every layer of the stack might be involved in any function; anything that claims a single layer owns a single job hasn't existed since at least IP over IP.

 

Joe