RE: ISCSI: Urgent Flag requirement violates TCP.

["Douglas Otis" <dotis@sanlight.net>]

Bernard,

Your assumptions about reordering is not accurate for WAN.  Should there be
more than one long-haul fiber in use, common in metro areas, the disparate
physical routes may induce out of sequence events.  Is such a case, SACK
reduces the negative effect.

Doug



> >More generally, along what sort of possibly lossy, possibly reordering
> >paths will iSCSI be trying to squeeze out Gbps+ rates?
>
> In a switched Ethernet environment operating over LAN/MAN/WAN,
> we will not see reordering, and only (very) occasional packet loss.
> So the concern would be to prevent a huge decline in transfer
> rate in the event of a loss. However, I think that can be
> addressed via a combination of RDMA and fast re-transmit.
> In this kind of environment, I would expect that SACK
> would only be of occasional relevance.
>
>