Re: IETF mailing list question on Storage over Ethernet/IP

[julian_satran@il.ibm.com]

Matt,

FC is a class of protocols. FCP provides reliable communication and so does
TCP.
The congestion control mechanisms of TCP are adequate (not the best) for
LAN and good for WAN. FCP congestion control is good for lan and quite bad
for WAN. The only FCP to FCP solutions we see out there are through a TCP
extender.
But for the basic application (SAN) they are technologically equivalent.
The question raised usually is that if FCP is not superior than why have
it?

Regards,
Julo

Matt Webster <mwebster@ieee.org> on 26/05/2000 16:21:00

Please respond to Matt Webster <mwebster@ieee.org>

To:   ips@ece.cmu.edu
cc:    (bcc: Julian Satran/Haifa/IBM)
Subject:  Re: IETF mailing list question on Storage over Ethernet/IP




I take issue with FC not providing reliable transmissions.  FC establishes
a dedicated link between the host and target, avoiding congestion once the
channel is established.  TCP/IP expects packet dropping... this in
storage?

Matt Webster


On Fri, 26 May 2000, Dave Nagle wrote:

>
> A few comments about this one.
>
> 1. FC does not provide reliable transmission.  It provides for error
> detection, but escalates recovery to "upper level protocol".  FCP-2 has
> improved this situation, but is not widely implemented yet.  One of the
> advantages of using a transport such as TCP is that link errors will be
> corrected in a manner that is transparent to the application protocol
> (SCSI).
>
> .
> .
> .
>
> Randy Haagens
> Networked Storage Architecture
> Storage Organization
> Hewlett-Packard Co.
> e-mail: Randy_Haagens@hp.com
> tel: +1 916 785 4578
> fax: +1 916 785 1911