[openib-general] Minutes for January 15, 2007 teleconference about OFED 1.2 development progress toward code freeze

[Caitlin Bestler]

openib-general-bounces at openib.org wrote:
> Roland:
> 	when RDMA is used, a message is transferred from card A (in node
> A) to card B (in node B), card B delivers the message to to
> user buffer, and sends ACK to card A, but ACK is lost due to
> switch fail. So process on node A get fail for this transfer,
> but process on node B check the memory  and get the message(success).
> 
> 	If send/recv(SRQ) is used, is it possible that process
> on node A get failure, but process on node B successfully get
> the message ?
> 

Yes, which is why the slight differences in IB vs. iWARP ack
semantics really aren't that important. The above scenario can
happen in both. If this is a problem, an application layer ack
is ultimately the only solution.