Multiple Connections per Session
================================

Starting in 1.4.20 IET has experimental support for multiple
connections per session (MC/S).

IET always supported multiple sessions by a given initiator, but
since SCSI command ordering can only be preserved within a session
this meant that commands could (and over time will) be issued
out-of-order which causes sequential operations to randomize over
time reducing the effective throughput considerably.

By utilizing multiple connections per session this eliminates the
need to use multiple sessions and MPIO on the host system, as the
abstraction appears to the host system as a single disk and it is
up to the initiator to handle the distribution of SCSI commands
over the connections of a session.

It should be noted though, that on the initiator side one should
use either MC/S OR MPIO for a target-initiator pair as on many
operating systems the behavior is undefined when using both. Linux
maintainers have decided to only support MPIO for it's initiators.
Microsoft supports both, but says that using both at once on a
given target-initiator pair is unsupported.

IET being an iSCSI target really doesn't care either way, as it
will process commands in the order per the RFC spec, but it is
highly recommend you don't use both at once unless MPIO is used in
a strictly active-passive fail-over fashion, while MC/S is used
active-active, any other combination of MPIO and MC/S will most
likely find you in trouble.