[openib-general] ip over ib throughtput

[Woodruff, Robert J]

>Note however that the relevant IB limit is the max ***message size***
which happens to >be equal to the ***IB*** MTU for the current IPoIB
(that runs on top of IB UD transport >service where IB messages are
limited to a single packet).

>A connected mode IPoIB (that runs on top of IB RC/UC transport service)
would allow IB >messages up to 2GB long. That will allow for much larger
(effectively as large as you 
>may ever dream of) ***IP*** MTUs, regardless of the underlying IB MTU.

>Diego 

The trade off is that a fully connected model requires each node to burn
a QP for every node in the cluster and thus does not scale as well as
the
UD model.  My guess is that if people need really high performance 
socket access, they will use SDP instead.

woody