> InfiniBand    InfiniBand      InfiniBand Verbs
> iWARP         InfiniBand      iWARP Verbs (subset of IBV, with
>                               specific connection establishment
>                               requirements that don't exist with IBV)
> RoCE          Ethernet        InfiniBand Verbs (but with different
>                               addressing because of the different
>                               link layer)
> OPA           OPA             InfiniBand Verbs

Verbs is an interface definition to hardware that has been twisted to be a 
software API and extended to expose vendor-specific implementation 'features' 
as extensions.  It is not a transport.

The device capability bits seems to have evolved to mean: vendor A implemented 
some random 'feature' in their hardware and wants all applications to now check 
for this 'feature' and change their code to use it.  Basically, what gets 
defined as a device cap is rather arbitrary.

- Sean

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