RE: iSCSI : Abort Task "connection allegiance"

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

Santosh,

> YP,
>
> "connection allegiance" implies the Abort Task is sent on the same
> TCP connection as the command. By sending the Abort Task on the
> same TCP connection, [and since it is sent after the command],
> the ordering is preserved. The abort will not reach before the
> command.
>
> The only case where the abort would reach before the command
> would be if the iSCSI layer at the target had discarded the
> command PDU [due to an iSCSI layer error]. In such a case, since
> the command will never be active at the target, the target
> would respond to the Abort Task indicating "No Task Found"
> or "Function Complete" which should be ok.

The advantage of multiple connections or multiple homing is removed if
connection allegiance is mandated.  The ability to recover from a seemingly
failed connection may include a request to restart using a different
connection.  Such request will likely be sent over a different connection if
there is a desire to migrate.  Connection allegiance was to allow
distributed state information to remain isolated.  This isolation is
problematic and not mandating allegiance ensures there will always be a
means to communicate intermediate states between connections.  Connection
allegiance should only be preferred.

Doug