SUMMARY: 100mbps full duplex

From: shridhar acharya (
Date: Thu Dec 25 1997 - 13:38:32 CST

hello again:

sorry for the long delay.

--------------here is what i had asked :

We have a GEO-RIM/FE 100 MBPS switch from UB. We would like to connect
an Ultra-2 ( on-board 100 MBPS ) to the switch in FULL-DUPLEX mode.

Would like to know if any of U are having such a setup and things
working fine ? I read a document from Sun saying that the full duplex (
802.3u ) standard is not yet a ratified one ( do not remember how old
the document is ); and that Sun's implementation MAY not work / reliably
work with third party hubs.

Note: UB's GeoRim/FE can work in fullduplex mode. This is documented.


although i didn't get an answer on the working of the above combination,
i did get confirmations on sun/100mbps/full-duplex working reliably with
bay and cisco switches.

some have suugested me to force the sun ethernet to the required mode
and some have asked me to have the latest patch applied on the hme
driver ( both of them i knew ).

all of 'em have been very valuable to me and would like to THANK
everbody who responded.

-----------------SUMMARY :

We have 2 Baystack 350T Autosensing 10/100Mbit Switches and connected
Ultra Enterprise 1 with Sunswidt and Ultra 1 Creator 3D to it.
With Solaris 2.6 everything worked fine, but with Solaris 2.5.1
the connection was only 100Mbit without full duplex.

The solution was to install Solaris Patch Number 104212-5 and after
the next reboot the connection to the switch was 100Mbit Full Duplex.
Mark A. Baldwin/

If you set your switch to 100MB full duplex, you can then add the
following lines to the /etc/system file on your Ultra 2:

set hme:hme_adv_autoneg_cap=0
set hme:hme_adv_10hdx_cap=0
set hme:hme_adv_100fdx_cap=1

This will force the Ultra 2 to full duplex. We use this configuration
on all our servers running 100MB. We use Cisco switches.
Lew Wolfgang:

We've done it by manually setting full duplex. Add
this to /etc/system:

SET hme:hme_adv_100fdx_cap=1
SET hme:hme_adv_autoneg_cap=0

You may also have to put your hub in full duplex manually too.
Marcelo Maraboli Rosselott:

It depends on the SUN dirver you have for your hme card..
pkginfo|grep hm
I have the latest version... 1.3 i think
i has full duplex mode, but i dont know how to set it.

"hi - pardon me, if this is redundant to u. the driver is
auto-negotiable on the mode. but, u could force it to the required mode
as Mark and Lew have suggested. this can be done either thru
kernel-patch file /etc/system as above or using ndd in the startup
scripts. eg. ndd -set /dev/hme hme_adv_100hdx_cap 0 ( disables half
duplex 100mbps ). in my opinion, forcing the driver to the required mode
is better than being negotiable ( kinda flaky ). one can avoid other
Benjamin R. Cline/

I've never worked with Ungerman-Bass equipment before, but our Ultra-2s
seem to work fine in full-duplex mode with our BayNetworks switches.
Make sure you've got the latest hme driver patch(es) from Sun installed!

thanks again to the generous,

This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:12:12 CDT