Re: summary of iSCSI meeting 22 June 2000

[julian_satran@il.ibm.com]

For all those concerned about the recovery discussion here are some
clarifications:

1. The whole discussion thread was related to an attempt to recover from
one TCP connection failure
in a session that has multiple TCP connections in order to fully exploit
the fault tolerance level users are expecting when using several
connections

2. As we are aware that stateful devices and operation idempotency are hard
to handle in general terms
we are currently contemplating mostly recovery mechanisms that are
"target-centric" (mostly target
initiated). Obviously we would love to be able to recreate a TCP connection
in exactly the state it got lost
but we are not aware of any such magic being available...



Julo

Julian Satran - IBM Research Laboratory at Haifa

David Robinson <robinson@ebay.sun.com> on 22/06/2000 20:30:05

Please respond to David Robinson <robinson@ebay.sun.com>

To:   Kalman Meth/Haifa/IBM@IBMIL
cc:   ips@ece.cmu.edu, scsi-tcp@external.cisco.com (bcc: Julian
      Satran/Haifa/IBM)
Subject:  Re: summary of iSCSI meeting 22 June 2000






meth@il.ibm.com wrote:

> Further discussion of what happens when TCP packets get lost, especially
if
>  they contain an iSCSI header.
> How well can iSCSI compete with FC if we are so dependent on TCP, with
its
> dropped packets.
>
> In the LAN, TCP packets are not generally lost and we should be
comparable
> to FC.
> Over WAN, can have packet loss and resulting complications, but that is
no
> longer competing with FC
> (which doesn't exist at all in the WAN).

Huh? TCP packets can never get lost, you either get the packet
or the connection is dropped.  There may be some delay as TCP
performs a retransmission which will be rare on LANs and not
so rare on WANs. I don't see how this is a FC vs TCP issue.

     -David