The IP over ATM Mailing List Archive by date

[Grenville Armitage <gja@thumper.bellcore.com>]

Tracy,

(I've put ip-atm back in - its important.)

>>> What if someone wants a single physical ATM NIC with single MAC addr to
>>> support two IP interfaces on the same 'logical' link? Each IP interface
>>> presumably needs a unique link local token, yet just using the 48 bit
>>> MAC value does not achieve uniqueness within the scope of the logical
>>> link. It would appear you need the SEL field.
	[..]

>>You seem to be trying to ask 1) "how can I use two different network
>>interfaces which would likely have the same IPv6 address"

nope.

>> or 2) "how can we use link local
>>addresses with greater than link-local scope"

nope.

Actually, I'm now contemplating a scenario where a single physical
machine, using a single ATM NIC, supports a number of independent,
'virtual hosts'. In an ATM environment doing this is trivial - each
virtual host's IP interface is built over a logical ATM interface,
themselves distinguished within the context of the single ATM NIC
by using different SEL field values.

Now consider two or more of these virtual hosts needing to
be 'on' the same link (logical, in the IPv6/ATM case).

Each virtual host is an independent entity, presumably with auto-config
needs, and certainly with the need to communicate with other
on-link {virtual}hosts. They need independent link local tokens (especially
if you consider a logical link that was router-less, and contained
a number of such virtual hosts in addition to other less virtual
hosts).

Rightly or wrongly this leads me to the ESI+SEL model for link
local token. (Interestingly, you cannot actually implement the
virtual hosts I mention above using IPv6-over-Ethernet as currently
defined.)

cheers,
gja
_________________________________________________________________________
Grenville Armitage                               gja@thumper.bellcore.com
Bellcore, 445 South St.      http://gump.bellcore.com:8000/~gja/home.html
Morristown, NJ 07960 USA          (voice) +1 201 829 2635 {.. 2504 (fax)}