iSCSI: too much recovery?

["Jon Hall" <jhall@emc.com>]

Hi,

I have some questions...

1) Why is there a header digest, is the TCP cksum not sufficient
   for iSCSI headers?

2) Why is the StatSN per connection and not per session?  Why not
   adopt the model that once the target sends a StatSN it may release
   the associated resources and need not retain that task's state?
   If the initiator does not see the StatSN it must recover and retry.

3) Similarly, why is there a SACK Request pdu?

4) And, why is there a Logout Response pdu?  Why not send a Logout
   and wait for the peer to close the connection.  If the connection
   does not close send another Logout and close the connection.

Implicit is an overarching question -- when errors happen will it be
possible for iSCSI peers to communicate in the manner that the spec
seems to assume?

Thanks,
Jon