Do we ever want to bind more than 8 multicast MAC addresses?

[Polychronis Ypodimatopoulos]

David Woodhouse wrote:
> On Fri, 2008-04-18 at 11:50 -0400, Polychronis Ypodimatopoulos wrote:
>   
>> what's possible? why not?
>>
>> David Woodhouse wrote:
>>     
>>> On Fri, 2008-04-18 at 11:43 -0400, Polychronis Ypodimatopoulos wrote:
>>>   
>>>       
>>>> Is it possible to associate shared activities with ethernet ports 
>>>> instead of whole multicast addresses? Then we would only need one single 
>>>> multicast address and do the filtering on the ethernet ports (eg IP is 
>>>> port 0x0800). At the very least, the multicast address is 6 bytes and 
>>>> the ethernet port is 2 bytes.
>>>>     
>>>>         
>>> That's possible, yes -- although you won't get the device filtering it
>>> for you then.
>>>
>>>   
>>>       
>
> Error. Question upside down. Please don't top-post.
>
> It's possible to do as you say -- to use different ports for different
> activities (although I read 'UDP ports' where you actually said
> 'ethernet ports' so perhaps I misunderstood).
>
> The device firmware doesn't speak IPv6 or Legacy IP, however -- and we
> wouldn't want it to, even if we trusted it. So it wouldn't filter for
> only those ports you're interested in; it'll give you all packets for
> that address.
>
>   
You're not following: Ethernet ports are bytes 12-14 (2 bytes total) on 
_all_ ethernet frames. IP has nothing to do with this. Instead of 
looking at the first 6 bytes (destination mac) for a specific multicast 
address, the filter should be looking at bytes 12-14 for a specific 
ethernet port.

Pol