RE: network controls are necessary

[Iljitsch van Beijnum <iljitsch@muada.com>]

On Sun, 8 Dec 2002, Tony Li wrote:

> |   Also, we may want to
> |   consider including a name space or address family
> |   identifier. That would
> |   make using IPv4 and IPv6 addresses as identifiers more
> |   easily backward
> |   compatible and knowing the nature of the host name makes
> |   selecting the
> |   right name to address mapping service easier.

> And this seems exactly backwards.

Hence the term "backward compatibility".

> If you can get your TCP
> connection to www.yahoo.com, why do you care if it's over IPv6,
> IPv4 or CLNP?

Actually I'm writing an article about the adoption of IPv6 so I'm
surfing the web while keeping an eye on my "tcpdump -i gif0 ip6 port 80"
output to see how many sites are v6 enabled. But that's not really
germane to this discussion.

What I was referring to was an AFI for the identifier, not for the
locator. So I don't care about whether the packets end up being IPv6,
IPv4 or CLNP, but I do care that "www.yahoo.com" is a FQDN and not an
IPv4 address, an IPv6 address, a CLNP NET, or a phone number. I want to
know it's a v4 or v6 address so I can build TCP packets that are
compatible with today's IPv4 or IPv6 TCP packets, even if I then choose
to transmit them over CLNP. I want to know if it's a phone number so I
can apply the processing best used for phone numbers rather than feed it
to the DNS and get nothing back.

> To put it more clearly: if we can make the system work with
> less information on the interface between application and stack,
> we should.  Yes, everything you take out of the interface will
> limit the power of the application, but we need to balance that
> against the complexity that it introduces.

> Nothing is perfect until you have removed all that can be removed.

On the other hand, something that can't be expanded later to accommodate
new needs isn't very perfect either.

Iljitsch