In your previous mail you wrote:
Francis Dupont wrote:
> In your previous mail you wrote:
>
> Is this just a layering question, an attempt to
> avoid layer violations? Or were there behind
> other goals, like allowing proxy ND?
>
> => both reasons. In the same kind of design ideas, it is
> forbidden to mix unicast and multicast between layers, i.e.,
> if the IPv6 destination is unicast, the link-layer destination
> MUST be unicast, and same with multicast in place of unicast.
Can you point me to the text that forbids this?
=> RFC 1122 3.3.6 but I recognize this needs to be clarify
for IPv6.
I was under the
impression that multicast emulation mechanisms (e.g. MARS, etc.)
use unicast link-layer destination addresses when the IPv6
destination is multicast.
=> in the case of MARS for ATM there is no real link-layer addresses
for the point-to-multipoint virtual circuits. Even if MCS are used
in fact we can argue the link-layer address is a set of addresses
with possible indirection.
The whole point of multicast emulation is to propagate
network-layer multicasts over unicast-only link layers - not true?
=> yes but the special mark for link-layer broadcast/multicast packets
is still needed.
Regards
[EMAIL PROTECTED]
PS: the exact quote is (see also TCP/IP illustrated V2 page 1101):
When a host sends a datagram to a link-layer broadcast address,
the IP destination address MUST be a legal IP broadcast or IP
multicast address.
A host SHOULD silently discard a datagram that is received via
a link-layer broadcast (see Section 2.4) but does not specify
an IP multicast or broadcast destination address.
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