Scheduled Transfer Protocol (ST)

[Costa Sapuntzakis <csapuntz@cisco.com>]

Thanks for bringing the ST protocol to our attention. I'm not sure
it fits all the requirements, though, because one of the goals of IPS
is to generate a WAN-friendly protocol.

Is STP designed for the WAN? I see no provision in the ST spec for 
TCP-style congestion control or even exponential back-off. In addition,
the Clear_To_Send mechanism as currently speced seems to add
a round-trip time to every transfer, increasing latency. 

As for the SCSI/ST spec:

Is there any mechanism for ordering tasks? For example, if you
want to enter several ordered tasks into a SCSI target, can you
issue them simultaneously, i.e. without waiting for an ACK?.

Thanks,
-Costa

On Tue, 22 Feb 2000, Aman Singla wrote:

> Hi,
> 
> Talking in context of the 3 layer protocol model, SI->Transport->IP,
> I'd like to bring to attention an ANSI draft standard protocol -
> Scheduled Transfer Protocol (STP).
> 
> The design of STP has been driven by requirements very similar to
> those outlined in the Storage of IP Design Framework, namely
> low-latency, high bandwidth, low CPU utilization, a measure of
> congestion/flow control built in, etc.
> STP can very easily fit in as the transport layer in the 3 layer
> protocol model. STP can be IP encapsulated, and a draft specification
> for SCSI over STP also exists.
> 
> STP has existed on Irix as part of the GSN infrastructure; SGI along
> with Genroco demonstrated a SCSI over STP solution interfacing a
> Origin 2000 server with GSN to a fibre channel raid network via a
> Genroco bridge, at CERN in October 1999.
> 
> STP is truly media independent, with support for GbE in the works.
> We recently made an alpha release of STP on Linux to the open-source
> community (http://oss.sgi.com/projects/stp), and going forward intend
> to fully support it on a variety of interfaces, starting with GbE.
> 
> More information about STP and the various drafts can be accessed
> off http://www.hippi.org/cDOCS.html.
> If there is interest in learning more about this protocol, we
> could arrange for a presentation/demo at one of the meetings for
> the proposed working group.
> (Note: STP is also refered to as ST in the marketing literature
> of various vendors - Genroco, Essential, PMR..)
> 
> thanks,
> 
> Aman Singla
> MTS, SGI
> 
> 
>