Full duplex at HUB?

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# 1  
Old 09-01-2002
Full duplex at HUB?

Ok at the moment I have a hub whit 5 computers connected to it. It's a 10/100 NetGear hub.

Ok I heard that there is some command I can run or a file I edit or something like that. But what the command/file/script/whatever does is tells you what connect speed it's connecting to the hub to.

I can force all ports to be fullduplex but doesn't mean it's going to connect at that.

What would be the best way to see what connection speed it would be running at the hub to the computer?


Thx in advance

# 2  
Old 09-02-2002
so far i know are hubs always half-duplex (switches are most tiems full duplex).this is because they make your network that way that it looks like that all connections are on the same line. if you send with one computer something to the hub they all recieve it.
# 3  
Old 09-02-2002
Re: Full duplex at HUB?

Originally posted by merlin
Ok I heard that there is some command I can run or a file I edit or something like that. But what the command/file/script/whatever does is tells you what connect speed it's connecting to the hub to.
You can execute the command `ifconfig -a` to get a list of current status. On my FreeBSD machine, for example:

        inet netmask 0xff000000 broadcast
        inet6 aa00::123:0abb:fe00:81f3%rl0 prefixlen 64 scopeid 0x1
        ether 00:00:00:00:00:00
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active

I can see that my NIC, rl0 is running at 100 Mbit currently set to full-duplex.
# 4  
Old 09-03-2002
Yes your both right. Sorry though I should have explained myself a little better.

There something like ndd -a or some type of command that you can use to see what speed the connection between a hub or a switch is.

I'm not sure of the command and the more I look into it the more I get myself lost (though I do find out good things to do with Solaris Smilie )

Does anyone know of a way that can tell you the connection speed between teh NIC and the hub/switch?

I'm running Soalris 7

# 5  
Old 09-03-2002
Here is some stuff from my SunOS notes. Note that other OS'es will probably handle stuff like this differently.

You can see the settings for the interface card with:
ndd -get /dev/hme link_speed
(0=10 mb and 1=100 mb)
ndd -get /dev/hme link_mode
(0=half and 1 = full)

But this doesn't mean that the hub port is in agreement. Hubs that can switch speeds and duplexes with have some way to check the port.

You want 100 mb and full-duplex. Usually the speed will be right. But often the duplex is wrong. You don't want to use autonegotiation, it fails too often.

If your interface card has the wrong settings, you can fix without a reboot by doing:

ndd -set /dev/hme instance 0
ndd -set /dev/hme adv_100T4_cap 0
ndd -set /dev/hme adv_100fdx_cap 1
ndd -set /dev/hme adv_100hdx_cap 0
ndd -set /dev/hme adv_10hdx_cap 0
ndd -set /dev/hme adv_autoneg_cap 0
(The last one will take a few seconds.)

The permanent fix so things will be cool after next reboot is to add some lines to /etc/system:
set hme:hme_adv_autoneg_cap=0
set hme:hme_adv_100T4_cap=0
set hme:hme_adv_100fdx_cap=1
set hme:hme_adv_100hdx_cap=0
set hme:hme_adv_10fdx_cap=0
set hme:hme_adv_10hdx_cap=0
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