[openib-general] Re: [swg] Re: private data...

[Fab Tillier]

> From: Sean Hefty [mailto:mshefty at ichips.intel.com]
> Sent: Thursday, October 20, 2005 1:30 PM
> 
> Using a bit in the REQ means that the higher level connection management
> protocol needs to receive and process CM REQs.  How does the REQ get routed to
> the higher level CM?  If it's based on service ID, then why is the bit needed
> at all?  If I'm routing based on this bit, then I could just as easily define
> this
> protocol to exist on a single service ID, and still route on service ID.  The
> upper level CM can then demultiplex to the correct application based on the
> addresses found in the private data.
> 
> Using a reserved bit is essentially adding a 65th bit to the service ID.

I disagree.  Using a reserved bit indicates that the first 32-bytes of private
data have a known format and can be evaluated by an entity shared by multiple
clients (the CMA).

The service ID on the other hand indicates what protocol is implemented over the
connection once it is established.
 
> In any case, I don't see how defining this private data format without
> specifying which service IDs use it is all that useful.

You can do both, but I think they are separate.  The protocol can be useful
outside the scope of DAPL or NFS/RDMA.  WSD could use it, and then use a
higher-level CM to do all the IP to IB path management rather than duplicating
it.

- Fab