It's brought a one which is the device and all paying Rodda to from rodded one to see if Ping's succeed
so paying ten more than two Ping's succeed.
But notice we are getting a message that there is a duplex mismatch between the Rodda and to the 20
951 switch.
So we're being told that there's a duplex problem here.
And on the switch we are seeing that there's a duplex mismatch on Foster.
Ethan it deserves three to the Rodda.
So we've been told that there's a duplex problem here but we also told that there's a duplex issue on
Fosset.
Ethan it is 0 4 to the 20 9:52 switch on Fosset.
Ethan It's 0 4.
So there's a problem here as well.
Now you may not be physically connected to the console and hence you may not see these issues.
That's a good reason to use Aslaug server or a management application from a company such a solar winds.
So let's ping rodder to again ping succeeds so pings aren't necessarily a good way to test for Duplaix
mismatches.
However I'll do an extended ping to that routers.
Let's try that again.
10:01 going to I'll send a thousand pings and I'm going to make the datagram size a large size.
So we want to send a lot of traffic on to the network and hopefully we'll encounter a problem.
And there you go.
We've got a message saying a late collision has occurred.
So this is a problem you may encounter one side may tell you that there are late collisions as you can
see over there.
We're getting a number of late collisions on the other side.
We're not seeing that
on the switch.
Show interface if there's zero slushed three
we're not seeing a lot of late collisions.
The configuration of that interface is set to a speed of 10 meg and Duplaix a fool.
But notice on the side show run interface if it's zero the side has its speed set to 100.
Let's confirm that show interface zero.
Notice the Duplaix is half speed is set in this example to 10 megabits per second.
So the router because it can't negotiate properly with the other device in this case the 28 on 50 switch
has set its speed to a valley of 10 make half duplex.
So the point to remember is when there is a mismatch the site that is set for half duplex will see a
late collisions on the connection.
But this only occurs when you sending enough traffic so he stented ping doesn't show that problem but
when a large amount of traffic is sent on this half duplex connection we are getting a late collusions
on the switch side striving to face if zero slash 3.
Notice the speed is full duplex 10 megabits per second.
Whereas on the router it's half duplex 10 megabits per second.
Even though I configured it to use 100 megabits per second it's using a failed back position of the
worst case scenario which is 10 make half duplex.
And in this case we're having that problem.
Notice this is 100 base TXI effects.
The side is 100 based x.
So in this example the router has gone for half duplex 10 megabits per second whereas the switch is
using 10 meg full duplex and hence we've got a duplex mismatch.
So in summary we get told by CGP that there is a duplex mismatch the local interface is not to using
full duplex whereas the other side is using full duplex pinging a device doesn't tell us that there's
a problem.
But when large packets are sent
uses main count the drops
put throughput and you may see late collisions.
So let me saturate that link again.
Send a thousand pings large datagram size
show interface zero slash three
notice we are now seeing the late collisions taking place on the interface.
So on the half duplex side we see this output of late collisions on the interface show interface is
zero.
Notice the number of late collisions has increased on the full duplex side.
We may get input errors such as CRC errors or out frames.
So in this example weve got 28 input errors 15 CCS.
We aren't seeing any runs but we are receiving duplex mismatch messages.