[swg] RE: [openib-general] round 2 - proposal for socket based connection model

[Yaron Haviv]

> -----Original Message-----
> From: Caitlin Bestler [mailto:caitlinb at broadcom.com]
> Sent: Tuesday, October 25, 2005 6:39 PM
> To: Tom Tucker; Kanevsky, Arkady
> Cc: swg at infinibandta.org; openib-general at openib.org
> Subject: [swg] RE: [openib-general] round 2 - proposal for socket
based
> connection model
> 
> 
> 
> > -----Original Message-----
> > From: openib-general-bounces at openib.org
> > [mailto:openib-general-bounces at openib.org] On Behalf Of Tom Tucker
> > Sent: Tuesday, October 25, 2005 2:56 PM
> > To: Kanevsky, Arkady
> > Cc: swg at infinibandta.org; openib-general at openib.org
> > Subject: RE: [openib-general] round 2 - proposal for socket
> > based connection model
> >
> > Arkady:
> >
> > I may actually have a constructive comment about the protocol
> > (private data format). One thing I noticed is that *almost*
> > everything in the private data header is available in the
> > native iWARP protocol header except the ZB and SI bits.  If
> > these bits become part of the canonical private data header,
> > then does that require an iWARP transport to use the header
> > too even though only two bits are useful?
> >
> > Sorry if this is a dumb question,
> >
> 
> I'm not sure I followed why these were needed myself.

I believe ZBTO and Remote Invalidation are mandatory in iWarp, right ?

There are two new RDMA features that are available in iWarp, and are new
to IB (optional in 1.2 version) 
A ULP that is supposed to run on both may want to know if the peer
supports those, so it can use the correct verbs

e.g. if the peer doesn't support remote invalidation the ULP will need
to use Send verb, and invalidate the FMR locally, if it does support it,
it can use the new "Send with Invalidate" verb which can improve
performance and security

I don't see why iWarp needs to negotiate it, CMA can just return true on
both bits in case its iWarp

This is a generic parameters that will be needed by more than one ULP,
that wants to make sure what verbs are supported by the RDMA generic
layer, that's why its in the generic portion of the header.

Yaron