Subject: RE: Fwd: Minutes / Notes

From: "Tony Li" <[email-masked]>
Date: Sun, 20 Jul 2003 20:00:57 -0700

Christian,

|    The question is  not whether we want to separate the 
|    location and identity function of IP addresses. Clearly, 
|    application developers have voted on that one. They just 
|    use the location function, and rely on other systems for 
|    identity. IP addresses should be locators, period.

That would be just fine, if only we could.  Unfortunately, we've
put the IP address in the pseudo-header checksum, so when your
locator changes, your connection fails.  The entire discussion
is about how we can use something else as an identifier.  

Creating an identifier space is one way.  Alternately, changing
the pseudo-header would be another, but we discarded that as
being even more unlikely.

|    The 
|    question is whether we want to pay an identifier tax at 
|    the IP layer. The tax will be significant: additional 
|    resolution procedures, additional overhead in the packets. 
|    The main justification of that tax would be to keep alive 
|    some long duration TCP connections, or some IPSEC 
|    sessions. This may benefit some applications, but the tax 
|    would have to be payed by everybody, whether they need the 
|    functionality or not. I would much rather not pay the 
|    identifier tax, and use a combination of application level 
|    sessions, TCP improvement, IPSEC fast rekeying, or maybe 
|    mobile-IP. There is no reason that everybody pays the tax 
|    when just a few benefit.

The tax is somewhat simpler than you submit.  Yes, it is an
identifier and a locator in some small proportion of the packets.
Perhaps just in the TCP SYN and SYN ACK.  It is certainly a
few more DNS records.  This can certainly be paid only by those
sites that want the benefits.  No one is requiring any changes
to vanilla IPv6 hosts.

The advantages go to those hosts that are multi-homed, and that
has typically been about 10% of the sites out there.  [Aside:
I suspect that this will grow as the Internet gets 'bushier'.]
The advantages also go to their correspondent hosts.

Now, if you don't want to play, I understand, but doing something
to fix the current situation is absolutely essential.  We cannot
have scalable routing with PI addresses.  These are also a tax on
everyone and a much higher tax where we can ill afford it.

Tony

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From: S Woodside <[email-masked]>
Date: Wed, 23 Jul 2003 19:44:19 -0400

> The advantages also go to their correspondent hosts.

It will IMO also grow if multihoming becomes easier ;-) With wireless 
networks it is much easier to multihome at the PHYSICAL layer than it 
was a few years ago.

simon