Duplex and speed negotiation is also important for connections between a PC and a switch.
In this example the PC is connected to the switch using the interface ethernet to at the moment the
speed negotiated is 100 megabits per second.
So here's the switch.
Show interface.
1 0 5 this interface is currently running at full duplex 100 meg on the switch and that's what's being
negotiated on the PC so we can see 100 megabits per second.
Now we could change some of the settings on the PC.
So if we wanted to we could change the speed and duplex negotiation at the moment it's using auto negotiation
but we could make a mistake and set it to 1 gigabits per second full duplex
on the switch.
We see that the interface has gone down it supposedly come up again.
So I'll just look at the duplex in the output the switches using 100 make full duplex and on the network
card it's actually moved down to 100 make.
Rather than using the gigabit speed that we configure it.
But if the PC had accepted that speed of 1 gigabits per second full duplex we would have had a duplex
and speed mismatch between the switch and the PC which would have caused problems.
Let's set the PC to 10 make and see if they can still negotiate properly.
So interface has gone down it's come up.
And in this case it has negotiated probably in gigabit ethernet even when set to manually the device
will still tell the other side what speed and duplex it's using.
So things are a lot better than they were in the past.
Let's set aside for a negotiation.
But what I'll do now is on the switch configure it manually.
So interface if 1 0 5 do show run interface.
EF 1 0 5 duplex and speed are not set but let's set the speed to 100 meg duplex to full.
So the configuration looks as follows.
Interfaces come up.
What is the side using it using 100 megabits per second.
Do you show interface if 1 0 5 piping to duplex that looks good.
Let's set the duplex to have and the speed
to 10
on the side.
Negotiation has taken place successfully.
So things are a lot better than they were years ago with Duplaix and speed.
But generally the recommendation is to use water negotiation of speed and duplex allow both sides to
negotiate to the highest speed and duplex that they both support.
So I'll try and break this by going to 100 full duplex
interfaces going down and come up.
But it's still successfully negotiated.
So it's still showing a speed of ten make Let's However configure it to go to the best possible speed
and duplex all set to use all the negotiation and on the switch will set the speed to a duplex to order.
And as we can see show interface if 1 0 5 include duplex the output shows full duplex 100 meg.
So it has successfully negotiated with the PC to use 100 make full duplex.
So in summary again or to negotiation is the way to go today if you are going to hard code.
Make sure that your hard code correctly on both sides.