Alexandru Petrescu wrote:

> Anyone proposed until now to update RFC2464 "IPv6 over Ethernet
> Networks"?  If not, I'd like to propose updating the following text:
> 
> > An IPv6 packet with a multicast destination address DST, consisting 
> > of the sixteen octets DST[1] through DST[16], is transmitted to the 
> > Ethernet multicast address whose first two octets are the 
> value 3333 
> > hexadecimal and whose last four octets are the last four octets of 
> > DST.
> 
> Not all Ethernet links/cards/drivers/firmware support this 
> 3333 value, 
> nor even Ethernet multicast groups.  Those who don't will 
> work fine with 
> v4 (6 times ff) but not with v6.  So some relaxing text 
> saying "either 
> 33:33:xx:xx:xx:xx or ff:ff:ff:ff:ff:ff" may help.
> 
> I don't understand why ND is so tight to the Ethernet 
> multicast in the 
> first place, but anyways.

Not sure I understand the problem.

For IPv4 multicast, the Ethernet address becomes 01-00-5E and the lowest 23 
bits of the IPv4 Class D address.

For IPv6, 33-33 and the lowest 32 bits of the IPv6 multicast address.

Don't all Ethernet cards and drivers understand the meaning of the LSbit of the 
first byte (the G/I bit)? As long as that bit is set to 1, won't all Ethernet 
switches know to flood the frame to all ports in the spanning tree?

Bert

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