1
00:00:00,460 --> 00:00:05,780
Duplex and speed negotiation is also important for connections between a PC and a switch.

2
00:00:05,820 --> 00:00:12,930
In this example the PC is connected to the switch using the interface ethernet to at the moment the

3
00:00:12,930 --> 00:00:16,370
speed negotiated is 100 megabits per second.

4
00:00:16,770 --> 00:00:18,230
So here's the switch.

5
00:00:18,240 --> 00:00:19,200
Show interface.

6
00:00:19,320 --> 00:00:29,970
1 0 5 this interface is currently running at full duplex 100 meg on the switch and that's what's being

7
00:00:29,970 --> 00:00:35,500
negotiated on the PC so we can see 100 megabits per second.

8
00:00:35,520 --> 00:00:41,950
Now we could change some of the settings on the PC.

9
00:00:42,390 --> 00:00:49,050
So if we wanted to we could change the speed and duplex negotiation at the moment it's using auto negotiation

10
00:00:49,560 --> 00:00:53,460
but we could make a mistake and set it to 1 gigabits per second full duplex

11
00:00:56,500 --> 00:00:57,790
on the switch.

12
00:00:57,790 --> 00:01:04,010
We see that the interface has gone down it supposedly come up again.

13
00:01:04,010 --> 00:01:16,290
So I'll just look at the duplex in the output the switches using 100 make full duplex and on the network

14
00:01:16,290 --> 00:01:19,620
card it's actually moved down to 100 make.

15
00:01:19,890 --> 00:01:24,780
Rather than using the gigabit speed that we configure it.

16
00:01:24,940 --> 00:01:32,190
But if the PC had accepted that speed of 1 gigabits per second full duplex we would have had a duplex

17
00:01:32,250 --> 00:01:38,270
and speed mismatch between the switch and the PC which would have caused problems.

18
00:01:38,330 --> 00:01:45,590
Let's set the PC to 10 make and see if they can still negotiate properly.

19
00:01:45,600 --> 00:01:49,530
So interface has gone down it's come up.

20
00:01:49,770 --> 00:02:00,170
And in this case it has negotiated probably in gigabit ethernet even when set to manually the device

21
00:02:00,170 --> 00:02:07,630
will still tell the other side what speed and duplex it's using.

22
00:02:07,650 --> 00:02:11,340
So things are a lot better than they were in the past.

23
00:02:11,790 --> 00:02:15,840
Let's set aside for a negotiation.

24
00:02:16,050 --> 00:02:21,190
But what I'll do now is on the switch configure it manually.

25
00:02:21,680 --> 00:02:27,520
So interface if 1 0 5 do show run interface.

26
00:02:27,530 --> 00:02:38,300
EF 1 0 5 duplex and speed are not set but let's set the speed to 100 meg duplex to full.

27
00:02:38,400 --> 00:02:41,620
So the configuration looks as follows.

28
00:02:41,730 --> 00:02:44,230
Interfaces come up.

29
00:02:44,320 --> 00:02:48,750
What is the side using it using 100 megabits per second.

30
00:02:50,610 --> 00:02:57,720
Do you show interface if 1 0 5 piping to duplex that looks good.

31
00:02:57,910 --> 00:03:03,610
Let's set the duplex to have and the speed

32
00:03:06,170 --> 00:03:06,980
to 10

33
00:03:09,990 --> 00:03:11,120
on the side.

34
00:03:11,490 --> 00:03:14,080
Negotiation has taken place successfully.

35
00:03:14,250 --> 00:03:19,380
So things are a lot better than they were years ago with Duplaix and speed.

36
00:03:19,380 --> 00:03:27,060
But generally the recommendation is to use water negotiation of speed and duplex allow both sides to

37
00:03:27,060 --> 00:03:32,690
negotiate to the highest speed and duplex that they both support.

38
00:03:34,080 --> 00:03:37,640
So I'll try and break this by going to 100 full duplex

39
00:03:40,410 --> 00:03:42,650
interfaces going down and come up.

40
00:03:42,780 --> 00:03:46,110
But it's still successfully negotiated.

41
00:03:46,230 --> 00:03:56,290
So it's still showing a speed of ten make Let's However configure it to go to the best possible speed

42
00:03:56,290 --> 00:04:13,790
and duplex all set to use all the negotiation and on the switch will set the speed to a duplex to order.

43
00:04:13,950 --> 00:04:23,370
And as we can see show interface if 1 0 5 include duplex the output shows full duplex 100 meg.

44
00:04:23,610 --> 00:04:31,060
So it has successfully negotiated with the PC to use 100 make full duplex.

45
00:04:31,080 --> 00:04:36,670
So in summary again or to negotiation is the way to go today if you are going to hard code.

46
00:04:36,780 --> 00:04:39,480
Make sure that your hard code correctly on both sides.