[openib-general] comments on DAT registry in OpenIB

[Caitlin Bestler]

On 6/30/05, Bob Woodruff <robert.j.woodruff at intel.com> wrote:
> Catlin wrote,
> >application --------->   DAT Layer -----------> RDMA Verbs -------->
> >model-specific code
> >               \                                          ^
> >                 \                                      /
> >                  \------------------------------------/
> 
> 
> Tell me how you are going to make the CM transport independent.
> You cannot, they are simply different for IB and iWarp.
> 
> We would have to do something like,
> 
> rdma_verbs_connect(xport_type, ....)
> {
>     if (xport_type == ib) {
>        do_sa_queries()
>        ib_connect()
>      }
>     else if (xport_type == iwarp) {
>        do_iWarp_connect()
>     }
> }
> 
> Thus all you have done is added another layer,
> 

True.

My assumption is that each transport would have its
own CM module with similar, but not identical APIs.

An application wants to go direct it could do the
if/else ifs on its own.

We could define polymorphic interface which all
CMs MUST support, but each would have its own
transport specific extensions.