Date:        Tue, 6 Feb 2001 16:24:23 -0800
    From:        "Paul Francis" <[EMAIL PROTECTED]>
    Message-ID:  <006b01c0909c$528dda60$1300a8c0@dellchan>

  | But I can't recall how it is a host decides when another host can be reached
  | via a site-local address, nor can I find where I read that text.

This is still one of life's mysteries I think - several ideas have
been floated, but nothing yet committed to a draft that I'm aware of.

The include placing the site locals in the DNS, and having clients
do a match on the global addresses to see if the site local should
refer to the same site (one that finds no attraction to me at all).

And having the client send from its site local addr (so the packet cannot
leave the site) to the remote global addr an ICMP saying "tell me your
addresses", and receiving a list that includes the site locals for the
destination (or receiving an ICMP error indicating an attempt to cross
the site boundary with a site local source addr).   (If the source doesn't
have, or doesn't want to use, its site local addr, then there's no point
doing any of this, may as well just use global addr of the dest a well).
This one I like - it adds a small delay in communications the first time
a connection is attempted to a new node (only for connections initiated, 
responses would never do this) but that is bounded by the RTT to the edge
of the site, which is usually of the order of a couple of ms.

kre

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