Re: Towards Consensus on TCP connections

[Ralph Weber <ralphoweber@compuserve.com>]

Jeff,

You missed a few:

  > SPI-4 ftp://ftp.t10.org/t10/drafts/spi4/spi4r00.pdf
  > FCP-2 ftp://ftp.t10.org/t10/drafts/fcp2/fcp2r04.pdf
  > SVP   ftp://ftp.t10.org/t10/drafts/svp/svp-r01.pdf
  > SBP-2 ftp://ftp.t10.org/t10/drafts/sbp2/sbp2r04.pdf

Every one of these is newer and represents more current thinking
on packetized SCSI protocols than GPP.

I'd be the first to admit that SPI-4 is easy to miss as a key
SCSI packetized protocol document, sorting your way through its
328 pages is no small feat.  Still, clause 14 (pdf pages 170-183)
defines a packetized protocol for the parallel SCSI bus and the
packet formats on pdf pages 175-183 are an important part of the
current packetized work.

It is also very important to note that SPI-4, FCP-2, and SVP are
active projects that share a goal of common packet formats to
simplify implementation of bridges between the parallel bus,
fibre channel, and VI.  While I don't wish to dogmatically cling
to this goal for IP SCSI, it definitely is worthy of consideration.
A particular issue in this regard is maintaining the LUN field
in each packet.

Thanks.

Ralph Weber
SAM-2 & SPC-2 Technical Editor


Jeff Fellin wrote:

> 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.
>
> Sincerely,
>         Jeff Fellin
>         MH 2A-352
>         (908) 582-7673
>         fellin@lucent.com