Re: please read: Clarification on GUID's universal/loc al bit

Hi Daniel,

It is good to know that the IBTA is working to address this issue.

If I understand your proposal correctly, once this change has been 
adopted by the IBTA, the correct way to build a IPv6 IID from a GUID 
would be:

(1) Start with the 64-bit GUID
(2) If the OUI portion of the GUID is equal to the specified value, 
then the "u" bit should be cleared (regardless of its original value) 
to indicate that the IID is locally administered.
(3) Else (if the OUI portion of the GUID does not equal the specified 
value) the "u" bit should be set
(regardless of its original value) to indicate that the IID is globally unique.

If I am understanding you correctly, this would always result in the 
proper setting of the "u" bit in IPv6 addresses.

What is the timeframe for an IBTA decision on this issue?  This is 
somewhat urgent, as we won't be able to finalize and approve the 
IPOIB specification until this issue is resolved in the IBTA.

Thanks,
Margaret


At 5:28 PM -0400 5/24/04, Daniel Cassiday wrote:
>The IBTA link WG (who is responsible for this mess in the first 
>place) has discussed this issus and is exploring solutions.
>
>The current thinking is not to use the u bit to indicate global 
>scope. Instead, any locally administered IB addresses (i.e. IB 
>64-bit Global identifiers) would use a reserved vendor identifier 
>(i.e. a reserved OUI).  Any IB 64-bit Global ID that does not use 
>this vendor tag will have global scope and be globally unique.
>
>In this approach, the IBTA would apply to the IEEE Registration 
>Authority for a OUI to be used for this purpose. The IBTA would also 
>clarify the IBA spec and add the requirement the "u" bit is ignored 
>in the EUI-64 (i.e. a vendor cannot have two EUI-64s differing only 
>in the value of the "u" bit)
>