[rbridge] All Rbridges Multicast Address

[Marshall Eubanks]

On May 17, 2007, at 2:28 PM, Dino Farinacci wrote:

>> Since we are an IETF Working group, it seems to me that we should
>> apply
>> to IANA rather than to the IEEE for the All-Rbridges multicast
>> address.
>> In fact, they are so plentiful that, as was discussed in the working
>> group earlier
>> (http://www3.ietf.org/proceedings/06jul/slides/trill-4/sld1.htm), I
>> can't see much reason not to apply for the next available block of 16
>> addresses, probably 0x01005E900000 through 0x01005E90000F, where ...0
>> would be the All-Rbridges multicast and the remaining 15 would be
>> reserved for future Rbridge use.
>
> FYI, 0x00005e is the OUI used for *IPv4* multicast addresses (ala
> 0x01005e). The IETF also has 0x233300 for IPv6 multicast addresses
> (ala 0x333300).
>

For 0x00005e 1/2 of the addresses (where the next bit is a "zero")  
were assigned
by Jon Postal to multicast, and the others (where the next bit is a  
"one") were
used for another project. I believe that this "other project" is long  
irrelevant, but
I have no idea who would release it, whether it is still being used,  
or whether NIC
cards etc. would reject it. If this was going to go forward, this  
would have to be done.


> It is of my opinion that any TRILL protocols that run right over an
> ethertype should not use the above OUI-based multicast addresses.
> That is, get an OUI from IEEE. Because right now IS-IS uses OUI
> 0x0180c2 which is not IETF assigned.
>
> And what's even more important, there may be assumptions in many
> implementations that if a MAC begins with 0x01005c, the enclosing

e not c

> packet is an IP packet. What comes to mind is IGMP-snooping switches.
> So let's just avoid this conflict or it will cause a lot of pain for
> vendors and users of such equipment.
>

I would agree. You could be setting yourself up for years of pain and  
frustration (people
will not go out and replace / upgrade thousands of IGMP-snooping  
switches just because you asked
them too).

> Dino

Regards
Marshall

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