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Thursday, July 19, 2007

Solaris NIC speed and duplex settings

In a newly created environment, we had a performance problem copying from app tiers to CUSTOM_TOP which is a NAS mount. On investigation it was found that the NIC speed on some of the app servers was set to 100mbps half duplex, whereas on switch side it was 1Gbps full duplex. This was corrected by the network team. However when the servers were rebooted during a SAN upgrade, the problem resurfaced. I googled to find out the Solaris command to check NIC speed and duplex settings and found this link:

The site is a goldmine of unix gotchas. This is the description of the site: "The purpose of this Web site is to document "lessons learned" as a Senior UNIX Systems Engineer for an application services provider in Minneapolis, MN. It contains notes that I wrote for my own and co-workers' reference; these notes may benefit others working on the same problems"

I am reproducing the article from google cache as it is not visible to me anymore:

Solaris NIC speed and duplex settings

The following is a Bourne shell script I wrote to determine the speed and duplex settings for all active network interfaces on a Solaris system. Thanks to William Favorite for fixing the script to work with two-letter network interfaces (e.g. ge0), and to Royce Williams for providing a patch to exclude subinterface information.

Download the script.

Example output:

Interface Speed Duplex
--------- ----- ------
hme0 100 Mbit/s full
hme1 100 Mbit/s full
hme2 100 Mbit/s full

Setting NIC speed and duplex

Solaris is often unable to correctly auto-negotiate duplex settings with a link partner (e.g. switch), especially when the switch is set to 100Mbit full-duplex. You can force the NIC into 100Mbit full-duplex by disabling auto-negotiation and 100Mbit half-duplex capability.

Example with hme0:

1. Make the changes to the running system.
# ndd -set /dev/hme adv_100hdx_cap 0
# ndd -set /dev/hme adv_100fdx_cap 1
# ndd -set /dev/hme adv_autoneg_cap 0

2. Make kernel parameter changes to preserve the speed and duplex settings after a reboot.
# vi /etc/system

# set hme:hme_adv_autoneg_cap=0
# set hme:hme_adv_100hdx_cap=0
# set hme:hme_adv_100fdx_cap=1

Note: the /etc/system change affects all hme interfaces if multiple NICs are present (e.g. hme0, hme1).

More information:

The /etc/system settings listed above are not supported for configuring ce Ethernet adapters during system startup; you may either use ndd commands in an /etc/rc?.d script or create a /platform/sun4u/kernel/drv/ce.conf file with appropriate settings.

Example: /etc/init.d/nddconfig


ndd -set /dev/ce instance 0
ndd -set /dev/ce adv_1000fdx_cap 0
ndd -set /dev/ce adv_1000hdx_cap 0
ndd -set /dev/ce adv_100fdx_cap 1
ndd -set /dev/ce adv_100hdx_cap 0
ndd -set /dev/ce adv_10fdx_cap 0
ndd -set /dev/ce adv_10hdx_cap 0
ndd -set /dev/ce adv_autoneg_cap 0

# ln -s /etc/init.d/nddconfig /etc/rc2.d/S31nddconfig

$ dmesg | grep ce0
Jan 20 11:05:01 crmmdb22 genunix: [ID 611667] NOTICE: ce0: xcvr addr:0x01 - link up 100 Mbps half duplex
Jan 20 11:05:15 crmmdb22 genunix: [ID 408822] NOTICE: ce0: no fault external to device; service available
Jan 20 11:05:15 crmmdb22 genunix: [ID 611667] NOTICE: ce0: xcvr addr:0x01 - link up 100 Mbps full duplex

Manually determining NIC speed and duplex

If you have ce or bge interfaces, use kstat ce and kstat bge, respectively, to return NIC settings. All other interfaces may use ndd to determine NIC settings.

ndd example with hme0, assuming "instance" is 0:

# ndd -get /dev/hme link_mode

0 -- half-duplex
1 -- full-duplex

# ndd -get /dev/hme link_speed
0 -- 10 Mbit
1 -- 100 Mbit
1000 -- 1 Gbit

To query a different NIC, such as hme1, set the "instance" to 1, and then perform the link_mode and link_speed queries above.

# ndd -set /dev/hme instance 1

Note: the ndd commands above must be run as root. Otherwise, you will receive errors such as "couldn't push module 'hme0', No such device or address."

ce Ethernet adapters

Older versions of the Sun GigaSwift Ethernet 1.0 driver do not support the ndd link_mode and link_speed parameters. You may either install the latest Sun GigaSwift Ethernet adapter patch (111883) or you may use kstat ce ce_device to get speed and duplex information for ce Ethernet adapters.

For example (from

$ netstat -k ce | egrep 'link_speed|link_status|link_duplex'

link_up - 0 down, 1 up
link_speed - speed in Mbit/s
link_duplex - 1 half duplex, 2 full duplex, 0 down

Host/link partner mismatch example

A large number of output errors or collisions may indicate a host and link partner mismatch. The following is netstat -in output from a system configured for 100 half-duplex while the switch was configured for 100 full-duplex.

Name Mtu Net/Dest Address Ipkts Ierrs Opkts Oerrs Collis Queue
ce0 1500 2707133478 25 2895422910 142310052 182856975 0

In this example, the switch was configured for 100 half-duplex and the system was configured for 100 full-duplex. Note the percentage of Ierrs/Ipkts (~ 1.7%).

Name Mtu Net/Dest Address Ipkts Ierrs Opkts Oerrs Collis Queue
qfe1 1500 1430247 24663 1779341 0 0 0


2007/07/10 -- Added e1000g interfaces
2006/11/29 -- Added dmfe interfaces, fixed bge and ce interfaces, many other modifications and fixes.
2006/04/27 -- Solaris 7 and earlier include subinterface information with netstat -i. Patch by Royce Williams to only query physical NIC interfaces.
2006/03/09 -- Fixed bge interfaces, added support for iprb interfaces, added "support" for le interfaces, modified script to only require root access if using /usr/sbin/ndd to determine NIC speed and duplex settings
2005/05/25 -- Fixed ce interface handling.
2004/09/15 -- Added support for ce and bge interfaces.

The script to show the NIC settings is available on I have kept a copy of it in our google group here as I was unable to access it from

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