[openib-general] IB Address Translation service

[Libor Michalek]

On Mon, Feb 28, 2005 at 09:55:50PM +0200, Yaron Haviv wrote:
> From: Libor Michalek
> > 
> > The two are not interoperable, they
> > reside in parallel, and succeed in producing much confusion. (IMO)
> 
> One note, the two can be made interoperable, if nodes that use IPoIB
> register them self in the ATS database as well (which has its merits for
> reverse resolution that cannot be satisfied by IPoIB), this way the
> nodes that just use ATS can locate the IPoIB ones.

  This relies on each node in a fabric keeping the information between
the two parallel methods in sync. Which leads to the question, why have
two independent methods for getting the exact same information? The
only logical answer is that there are some nodes which can only use
one of the methods. In which case the two sets of data are not identical,
because of these nodes, which succeeds in producing much confusion. Not
to mention the race conditions between keeping a centralized database (ATS)
in sync with the distributed mechanism. (ARP)

  For these reasons I cringe at hearing IP address and ATS in the
same sentence, I really wish DAT had chosen a different name for
the addresses.

  Really, we all discussed this years ago in the IETF, the merits of
using broadcast vs. centralized data store, and a solution was
developed. This is why open standards bodies are so useful.

> Anyway the merits if the proposed API goes much beyond the use of ATS,
> so I hope we don't just hang on that one.

  Agreed, there is certainly a lot more to discuss then just ATS and ARP.


-Libor