AIX

Connecting network adapter from 100MB switchport to a 1GB switchport.
Trying to verify actual switchport speed.

While connected to 100MB switchport
lsattr -R -l ent0 -a media_speed shows:
10_Half_Duplex
10_Full_Duplex
100_Half_Duplex
100_Full_Duplex
1000_Full_Duplex
Auto_Negotiation

lsattr -EH -l ent0 -a media_speed shows:
attribute value description user_settable
media_speed 100_Full_Duplex Media speed True

netstat-v shows (among other things):
Link Status : Up
Media Speed Selected: 100 Mbps Full Duplex
Media Speed Running: 100 Mbps Full Duplex

After connecting to 1GB switchport.
Regain "ping" in seconds.

chdev -P -l ent0 -a media_speed=1000_Full_Duplex
ent0 changed

lsattr -EH -l ent0 -a media_speed
attribute value description user_settable
media_speed 1000_Full_Duplex Media speed True

However:
netstat-v shows (among other things):
Link Status : Up
Media Speed Selected: 100 Mbps Full Duplex
Media Speed Running: 100 Mbps Full Duplex


What speed am I actually connected at??

Thanks,
-dog

What type of adapter and what do the LEDs / lights on the card show?

Looks like you are now set to 1000Mbps but netstat is out of date for the "Selected" and who knows what went wrong with the "Running" output.

oslevel -s may also be useful.

1) "chdev -P" changes the ODM but not the running device. To actually change the settings you would now need to deactivate the device with "rmdev -l" and activate it again with "mkdev -l". However, you have no guarantee that the switch would react to this change. This might lead to problems as the autonegotiation as defined in the Ethernet Standard takes place only once on first connection before a data packet has been send. If the switch does not react on switching the adapter off and on again the speed might stay at 100 Full or Half without netstat being able to tell you so.

2) "lsattr -El" reads the information from the ODM but not from the running device. So yes, because you changed the ODM you get the information what settings are there. However, that does not have to be the current settings of the device and in your case it definitely is not.

3) Never use different settings on switch and adapter side. If your switch is set to autosense your adapter must be set to autonegotiate too. If your switch ist set to a fixed value, set the adapter settings accordingly. With different settings you have a good chance of ending with Half-Duplex because the standard tells the port to work like this if there are problems during portspeed settings detection. Next to routing problems this is a major reason for slow network connections.

Coming back to what you asked initially. You probably are at 100 Full but you cannot be 100% sure as the netstat output is not always reliable here.