HOIW TO FORCE NIC TO FULL DUPLEX 1

[teletubby5e]

I have an AIX server that is fed from a 10/100BT switch. The link light is at 100Meg but the Duplex is at half. I have used the ifconfig and the netstat -v commands that provide some information but nothing about the speed and the duplex mode. I am relatively new to the AIX world, but am trying to chase a source of collisions / retransmits on our network, and thought that I would start at the NIC issue. Thank you.

Jeff

 

[admincff]

Yopu can force the duplex/speed mode by :

smit devices / communications / Ethernet /Adapter /change
Characteristics and on "media speed", choose by F4 in the list the value you want to modify....


But before you should have to detach your network interface

Smitty tcpip / Further Configuration / Network Interface /
Network Interface Selection / Change Configuration /
Choose your interface ..
And in "Current State", F4 to choose "detach".

After changing your media speed,
smit tcpip / Minimum Configuratin, choose your interface and "enter".....

 

[RMGBELGIUM]

Don't forget to set the speed of your adapter in the SMS menu (at boottime), this one is often forgotten...

greetz,

RMGBelgium

 

[teletubby5e]

Many thanks! That was perfect using the SMIT method. I will have to wait until a maintenance window to change and do the reboot. Is there aquick and dirty way to status it from the server after I am finished similar to the ifcong? to confirm that it wasn't set to autonegotiate or to half duplex/ Thanks again for the great info! Jeff

What is the difference between the SMS menu and SMIT?

Thanks again!

 

[jprabaker]

lsattr -El ent0 (or whatever) will show the settings.

You don't need to reboot for this change to take effect, you just need a litle outage (2 mins if your quick!!) to disable the card, change the settings and then enable again - but make sure the port on the switch is also set to 100 Full Duplex!

SMIT is used to perform system admin on a running system. SMS are utilities that perform tasks on a system in a preboot stage - like setting up boot lists, performing microcode updates, network booting etc...

 

[teletubby5e]

Perfect ....

lsattr -El ent0 tells me that the card is capable of full deuplex, however is not operating in that capacity. so the smit command utilizes what i would normally use (the chdev command) it looks like. many thanks to all.

full_duplex no <== current setting

Full duplex True

 

[teletubby5e]

got this from comp.unix.aix:

>changing the media speed of an ethernet adapter.
>
>/usr/sbin/ifconfig en1 down detach
>/usr/sbin/ifconfig et1 down detach
>/usr/sbin/chdev -l ent1 -a media_speed=100_Full_Duplex
>/usr/sbin/chdev -l en1 -a state=up
>/usr/sbin/mkdev -l inet0
>
>During the change you will lose connection on the interface.
>
>rgds, wijnand

 

[haexpert]

What you can also do put the above commands into a script and then run the scripts, it only takes about 30 secs for the script to complete.

 

[letis]

Hello,

to check at what speed you are currently running :

entstat -d en0 | more


and somewhere in the output you will have :

Link Status: Up
Media Speed Selected: Auto negotiation
Media Speed Running: 100 Mbps Full Duplex


regards,