how can we change the nic card speed
please explain through commands & steps ????
and i want to change NIC speed 100 --1000Mbps
and what is full & half duplex gives
thanks in advance
Well, it's a big question. First you need to know what the NIC will support and what the network switch will support. From them, you can decide what is the best settings. It is best to get the switch port forced to match the speed of your NIC as auto-negotiate may not always work or may cause overheads if it ferequently tries again looking for a faster card.
The process of setting it will depend on your operating system, e.g. for AIX you can:
chdev -a speed=1000_Full_Duplex ent0
but that is AIX only. Solaris, HP-UX and other flavours all have their own commands.
To perform the action, you will also need to stop the network card, so plan your downtime, work out how to do it from the console only and note all the current configuration before starting. On AIX you sometimes have to delete the interface and boot so that it not in use. This means you will have to input the IP address again, netmask and default gateway again.
Full Duplex vs Half Duplex
Simplex is the sending or receiving of data on a NIC. Duplex is the ability to send and receive data. Dimplex is a radiator manufacturer, which probably isn't any use in this forum.
Full duplex (often lazily called duplex) means the ability to send and receive data at the same time, where half duplex is the ability to only do one at a time.
Basically, when deciding what to set the NIC and the switch port to be, use the highest common speed and the best ???plex that they both work at. I'm guessing that simplex is likely to be out, but if either the NIC or the switch only supports half duplex, then that is what you are stuck with. We have hit very serious problems where when the settings didn't match, to a half duplex NIC and a full duplex switch port. It worked okay until someone did an FTP. The normal telnet/screen traffic was handled okay, but when the FTP kicked in, the dropped packets went through the roof and uses were getting horrible response and partial screen displays. The FTP was also horribly slow.
We had to force the switch port to only be 10M Half Duplex and then performance was wonderful for the FTP and the telnet users were unaffected.
I am, of course, assuming that the NIC and the switch are reasonably close to each other. You may have to lower the speed if the cable it particularly long, but I can't tell you what the limits are. It is just for the connection of the NIC to the switch, not all the way to the user terminal/remote server/whatever.
I hope that this is useful, but if not, do ask more questions.
Robin
Liverpool/Blackburn
UK
well,
thank you for reply
but i need on solaris not for Aix
please give steps for Solaris operating system
\thank you again in advance
U need to study the Sun documentation first.
use the ndd command for solais and refer this link for more details.
C H A P T E R 3 - Configuring Driver Parameters
thanks vinay
atleast you send some information
The way to do this depends on the type of NIC you are using.
For some types you make entries in /etc/systems, like these to set all qfe-interfaces to 100 MBit Fullduplex.
set qfe:qfe_adv_autoneg_cap = 0
set qfe:qfe_adv_100fdx_cap = 1
set qfe:qfe_adv_100hdx_cap = 0
set qfe:qfe_adv_10fdx_cap = 0
set qfe:qfe_adv_10hdx_cap = 0
set qfe:qfe_adv_100T4_cap = 0
If you have ce interfaces, entries in /etc/system do not work. You have to create an init-script like this (which sets only ce0 to 100 MBit Full) and make sure, it is run at system boot.
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
Some NICs can't even be configured using the ndd command. Instead you have to make entries in the driver's config file under /kernel/drv. The format of these entries is driver dependent.
Consult the NICs documentation or places on the internet (like this forum) to find out, which kind of configuration is supported and which not.
Finally: please use interface fixation only as a last resort. Autonegotiation is today's technology and for gigabit ethernet it is mandatory anyway.
I fully agree with last hergp comment. Ethernet settings should be set to auto negotiate. This should just work. If it doesn't, have the vendors fix their hardware instead of trying to mess with settings.
This is from experience. I have seen a lot of networking issues in various sites and plenty of them were due to wrong settings, the most common being one side auto-neg while the other one had fixed speed/duplex mode.
This is somewhat similar to IP settings. If you have a correctly configured dhcp server, things usually work fine. If you have fixed addresses and let people setting them, you quickly end up with duplicate IPs, wrong DNS settings, wrong default routers and so on.