RE: New List: rdma@cisco.com: to discuss RDMA

["Douglas Otis" <dotis@sanlight.net>]

Charles,

With respect to SCTP, features added by a TCP option for RDMA are not needed
to support alignment and out of sequence processing that ultimately alters
the TCP API.  SCTP adds these features without disruption or modification to
TCP.  The intent of VI is to allow scatter/gather function to handled by the
target.  A safer scheme would be to adhere to SCSI conventions and implement
zero copy and out of sequence processing using SCTP and SAM structures
related to locally pre-arranged transfer structures.  This would keep the
initiator or client in intimate control of memory and not reliant on targets
eliminating boundary checking.  Such a feature will slightly impact SCTP to
add a means to generally encapsulate a data payload associated with
structure of pointers equipped with scatter-gather lists and relative
offsets.  Specifically, this could be defined as the FCP structure data
structure in SCSI implementations.  I would whole-heartedly endorse such
features within SCTP.  I would dissuade such features from being added to
TCP.  One could view the scatter-gather list structure as a token to be used
by the target in more conventional VI methods.

Doug

> -----Original Message-----
> From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
> Charles Monia
> Sent: Wednesday, September 27, 2000 11:49 AM
> To: csapuntz@cisco.com; Jim Williams
> Cc: ips@ece.cmu.edu
> Subject: RE: New List: rdma@cisco.com: to discuss RDMA
>
>
>
>
> > -----Original Message-----
> > From: csapuntz@cisco.com [mailto:csapuntz@cisco.com]
> > Sent: Wednesday, September 27, 2000 10:16 AM
> > To: Jim Williams
> > Cc: ips@ece.cmu.edu; csapuntz@cisco.com
> > Subject: Re: New List: rdma@cisco.com: to discuss RDMA
> >
> >
> >
> > Does anybody on the list object to specifying an RDMA mechanism for
> > use with iSCSI? Does anybody on the list object to mandating an RDMA
> > mechanism? Please include your reasons.
> >
>
> I'd object to mandationg the use of RDMA in iSCSI. However, I
> would support
> structuring the spec so that an RDMA transport mechanism could be used
> underneath (I guess that's motherhood). If the iSCSI folks decided this
> wasn't a priority issue, that's ok with me too.
>
> Charles
>