Re: TCP limitations (was Re: ISCSI: Urgent Flag requirement violates TCP.)

["Jim Williams" <jimw@giganet.com>]

Alignment of VI is recommended for those implementations that
are able.  It is not a requirement and therefore
does not modify TCP.  The urgent pointer mechanism is a proposal
paralleling the iSCSI discussion.  I would expect to ultimately
converge on whatever is decided within the ips group.

 - Jim


----- Original Message -----
From: Douglas Otis <dotis@sanlight.net>
To: Matt Wakeley <matt_wakeley@agilent.com>; <ips@ece.cmu.edu>
Sent: Monday, November 27, 2000 5:16 PM
Subject: RE: TCP limitations (was Re: ISCSI: Urgent Flag requirement
violates TCP.)


> Matt,
>
> This draft
> http://www.ietf.org/internet-drafts/draft-dicecco-vitcp-01.txt
> uses two methods to discover data, one is an alignment of VI and TCP
> segments as the recommended  implementation, and the other is a repeat of
> the urgent pointer method.  Either way, a proposal that alters TCP.  Not a
> simple shim, otherwise it also does not allow out of sequence processing
for
> direct and immediate placement of data, the goal.
>
> Doug
>
> > csapuntz@cisco.com wrote:
> >
> > > Given that shim protocol requires no changes to the TCP in the sender,
> > > it is currently my favorite way of doing RDMA.
> > >
> > > -Costa
> >
> > Please see Jeff's message on 10/26.  If you don't have framing,
> > when you lose
> > a segment, you need to buffer generic TCP segments on the NIC
> > before you can
> > "RDMA" them somewhere, because you don't know where the "RDMA"
> > information is
> > in the "byte stream".
> >
> > -Matt
> >
>
>