Re: IPDS performance - Twinax vs. TCP/IP

[Paul Tykodi <ptykodi@xxxxxxxxx>]

Hi Steve,

The throughput of the twinax protocol is 1 MB per
second while Ethernet TCP/IP is 10 Mb per second or
faster. The default packet size used for twinax
transmission of IPDS data is 256 bytes while the
default packet size for TCP/IP transmission of IPDS
data is 1024 bytes (four times more data per packet).

These network transmission characteristics allow the
TCP/IP method for transmitting IPDS data to support
printers with higher PPM (pages per minute) ratings
than twinax. In my experience, the twinax and TCP/IP
methods can drive printers at engine speed up through
about 50 PPM. Anything above this value and the twinax
performance begins to be a significant bottleneck.

The other issue is that the TCP/IP driver for IPDS
printers is included in the software known as Print
Services Facility (PSF). By standardizing on one
software product to deliver the driver to all e(logo)
server platforms, IBM saves money by not having to
support special unique implementations of the required
driver on different server platforms. The PSF version
for OS/400 and i5 OS is an extra cost option.

It happens that OS/400 is old enough that it pre-dates
the implementation of PSF across all e(logo) server
platforms. Specific to twinax attached devices, there
is some legacy code in OS/400 that produces IPDS
without requiring PSF. If you have been driving your
IPDS capable printers with this legacy code, a
conversion to TCP/IP connectivity will require paying
for a PSF/400 license for each IBM AS/400 or iSeries
host being converted in order to obtain the necessary
software print driving capabilities.

HTH

Best Regards,

/Paul
--
Paul Tykodi
E-mail: ptykodi@xxxxxxxxx

>date: Tue, 7 Sep 2004 16:55:14 -0500 
>from: Steve Morrison <smorrison@xxxxxxxxxxxxx>
>subject: IPDS performance - Twinax vs. TCP/IP
>
>Has anyone here used IPDS printing over both twinax
>connected printers and TCP/IP connected printers? 
>Is there a noticeable performance difference?
>
>I just confirmed that we can connect one of our 
>(currently twinax connected) IBM IPDS printers over
>TCP/IP, but don't have a permanent line connected to
>it. Is it worth the time and effort to make this
>switch?
>
>Are there other advantages to switching an existing
>printer to TCP/IP connection?
>
>Steve Morrison
Beacon Insurance
940-720-4672 



                
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