Re: [arch-d] FYI: closure of the IAB Stack Evolution program

[Fernando Gont <[e-mail]>]

On 25/8/19 22:41, John Leslie wrote:
[,,,]
> 
>> You may call that a middle-box tax if you want. But as long as you are
>> willing to pay that tax, you can of course deploy new transmission
>> control protocols over the Internet. Most people will call them
>> transport protocols.
> 
>    Actually, what we call them _does_ make a real difference. I'd be happy
> to call them "transport protocols"...

If anything, QUIC without UDP encapsulation is as much of a transport
protocol as IPv6 is as network layer protocol.

If you tried to use IPv6 natively (i.e., a single network layer in the
resulting stack) on the same network on which we employ IPv4, you just
can't: there's only partial support for IPv6, and you need to tunnel it
over something that works (IPv4) to overcome that. Yes, IPv6 is a
network-layer protocol, but if folks assumed that it can be readily
employed on the whole big-I Internet, that would be, of course, a false
expectation: there's lots of parts of the network that simply lack
support for it.

The same analogy applies to transport protocols: lots of portions of the
network just don't support anything else other than, say, TCP and UDP.
In some cases, because of NATs, in others because of firewalls, or boxes
that will drop packets if they cannot tell whether something is a
transport protocol or unknown EH, etc. That's when you end up stacking
one transport over another.

I don't think this is a matter of vocabulary, but one of architecture:
In away, protocols don't work because, for one reason or another, the
layer you had has become broken (into islands, if you want), and you
need to pile protocols of the same rank on top of each other for the
system to work.  In the case of transport, UDP is of course convenient,
because it allows your packets to "get through" while doing as little as
possible. But is a protocol, not a "tax".

If you want to call UDP "middle-box tax", I guess we should also call
IPv4 a "middle-box tax" (or similar name) when tunneling IPv6 over IPv4.


-- 
Fernando Gont
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