RE: Towards Consensus on TCP connections

[Jim McGrath <Jim.McGrath@quantum.com>]

It is perfectly SAM compliant to restrict the size of the LUN space if you
wanted for a given transport (as an obvious example, parallel SCSI has only
a handful of LUNs per target).  I'm not saying it is the right thing to do,
only pointing out that the 64 bit LUN in SAM can be restricted (and is today
as a matter of course).

Jim


-----Original Message-----
From: Douglas Otis [mailto:dotis@sanlight.net]
Sent: Wednesday, August 16, 2000 2:18 PM
To: Jeff Fellin; ips@ece.cmu.edu
Subject: RE: Towards Consensus on TCP connections




> -----Original Message-----
> From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
> Jeff Fellin
> Sent: Wednesday, August 16, 2000 11:41 AM
> To: ips@ece.cmu.edu
> Subject: Re: Towards Consensus on TCP connections
>
>
>
> Folks,
> After reading all the discussion and debate on this issue, I decided to
> research if the SCSI standards (T10/X3) have done with developing other
> transport protocols, and how those protocols dealt with connectivity
> issues between the endpoints. For the most part the other transport
> protocols SCSI over Scheduled Transport (SST), which is a working draft
> and the SCSI-3 Generic Packetized Prococol (SCSI-GPP), which is a proposed
> technical report have a concept of a Logical or Virtual connection. This
> Logical or Virtual connection has at least one connection through the
> network, but may have more up to endpoint configuration parameters. So,
> it appears the other groups have not come to a consensus as to
> the approach.
>
> Most of the drafts are available on the T10's web site:
> 	www.t10.org
>
> Except for the definition of the Scheduled transfer protocol, which is on
> T11's web site:
> 	www.t11.org
>
> The most interesting thing I came up with is the SCSI-GPP definition is
> written to allow connections over IP networks. Annexes E and F describe
> the mapping and processing capabilities. If this is a work in progress
> should we take advantage of there previous start and work with T10 to
> have a better definition of a protocol for storage over IP?
>
> What I understand from a quick read of the SST and SCSI-GPP protocol
> definitions is they have dealt with the issues of security, error
> recovery,
> connection management, transfer of SCSI bus control signals (bus reset,
> abort tasks.
>
> If we don't use the SCSI-GPP than I propose changing the one LUN per
> TCP connection group to be a SCSI target id that multiplexes all LUN's
> of the target id onto the connection group. I believe this will decrease
> the amount of connections and provide data channels for large transfers.

see: ftp://ftp.t10.org/t10/drafts/gpp/gpp-r09.pdf

Jeff,

There is a considerable difference between the SCSI-GPP and iSCSI.  With GPP
there are only 256 possible LUNs per target (among other notable features).
Under iSCSI, there are 18,447,000,000,000,000,000 possible LUNs per target
and this 64-bit LUN value is implied in some cases.

Doug