RE: ISCSI: Urgent Flag requirement violates TCP.

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

Silvano,

Without modifying the TCP sender, there would be no way to assure if any PDU
within a segment has an urgent pointer defining its location.  That would be
true for any PDU- first, second or third within a segment.  TCP allows a
single pointer to be defined at any time but there could be hundreds of PDUs
outstanding at the sender.  There is little assurance of pointer accuracy as
most machine's pointers do not resolve to the byte and TCP never intended a
urgent pointer to be used as a record mark.  This urgent pointer simply
defines a change in state where the actual pointer is not directly presented
to the application but used to expedite processing.

Doug

>
> At 04:28 PM 11/7/2000 -0800, Matt Wakeley wrote:
>
> ...
>
>
>
> >For example, if the following iSCSI messages are sent:
> >
> >Command A sent to target  ->
> >Command B sent to target  ->
> ><- target sends data/status for command A
> ><- target sends data/status for command B
>
>
> In the previous example, if Command A and Command B are
> transmitted in the same segment, do you care to specify if the
> urgent pointer points to the first or second command?
>
> -- Silvano
>
>
>
>
> Silvano Gai
> Cisco Systems                  Empowering the Internet Generation
> 170 West Tasman Drive                         Tel. (408) 527 2690
> San Jose, CA, 95134-1706                      Fax. (408) 527 2690
>                                                    sgai@cisco.com
>
>