1 00:00:00,810 --> 00:00:12,340 So we now need to fix this link between 20 and on 51 and 20 9:52 both switches are showing messages 2 00:00:12,340 --> 00:00:14,090 that there's a duplex problem. 3 00:00:15,210 --> 00:00:17,380 So CGP does a nice job here. 4 00:00:18,800 --> 00:00:27,680 Of showing us that there's a problem rather show run interface if zero slash four we can see the speed 5 00:00:27,680 --> 00:00:36,370 and duplex are hard coded show run interface if Zeerust last for on the side it's 100 half duplex on 6 00:00:36,370 --> 00:00:42,480 the side it's 100 full duplex. 7 00:00:42,630 --> 00:00:51,170 So that's a simple fix of setting the duplex to full the interface has gone down and comes up again. 8 00:00:53,470 --> 00:00:56,200 And hopefully that's resolved the problem. 9 00:00:56,200 --> 00:01:06,290 We could play the counters as an example when if Syria slash for and do the same here play a count as 10 00:01:06,550 --> 00:01:11,230 if 0 4 and then we could. 11 00:01:11,270 --> 00:01:17,050 After a while we look at those counters and see if we find any problems. 12 00:01:17,190 --> 00:01:25,330 But that should have solved the problem of a duplex mismatch to confirm it show interface F-0 slash 13 00:01:25,340 --> 00:01:30,910 for right at the top here we can see. 14 00:01:30,930 --> 00:01:32,310 So here's the command. 15 00:01:32,610 --> 00:01:39,440 Here's the speed and duplex of the interface interfaces up up and it's connected show interface. 16 00:01:39,450 --> 00:01:50,400 If there's Slash for on switch to he has the command once again Duplaix and speed are shown here as 17 00:01:50,400 --> 00:01:51,180 well. 18 00:01:51,450 --> 00:01:54,280 Interfaces up up and it's connected. 19 00:01:54,300 --> 00:02:04,980 We've not seeing any errors on the interface and on this one we are also not seeing any errors. 20 00:02:04,980 --> 00:02:11,780 So that hopefully has resolved the problem on this link and this link. 21 00:02:11,820 --> 00:02:20,310 So be careful hard coding speed and duplex what a negotiation may negotiate correctly but it may not 22 00:02:21,000 --> 00:02:24,080 generally today with gigabit and foster lengths. 23 00:02:24,090 --> 00:02:29,390 Your problems are not as bad as they used to be on 10 100 links. 24 00:02:29,820 --> 00:02:37,090 Let's see what happens if we can figure speed and duplex on one site and leave the other side for negotiation. 25 00:02:37,590 --> 00:02:41,970 So on 29 51 we will configure this interface 26 00:02:44,830 --> 00:02:53,810 with a speed of 100 Duplaix of full interfaces gone down interface will hopefully come up. 27 00:02:53,900 --> 00:02:58,740 And there you go. 28 00:02:58,760 --> 00:03:07,200 Here is the 30 750 and we can see that it's complaining about a duplex mismatch. 29 00:03:07,410 --> 00:03:19,410 So show run interface if 0 EF 1 0 3 No Duplaix will speed as being configured on the interface show 30 00:03:19,410 --> 00:03:19,990 interface. 31 00:03:19,990 --> 00:03:26,340 EF 1 0 3 the side is using 100 make half duplex whereas the side 32 00:03:29,660 --> 00:03:35,040 is using 100 make full duplex. 33 00:03:35,160 --> 00:03:43,750 So if you have one side configured for negotiation and the other side is hardcoded you may have a problem 34 00:03:43,780 --> 00:03:49,890 because the site is not negotiating with the other side and the side may take a fallback position. 35 00:03:50,110 --> 00:03:56,800 Sometimes it's able especially on gigabit and Lady interfaces to still work out what the other side 36 00:03:56,800 --> 00:04:01,330 is using and set its duplex and speed accordingly. 37 00:04:01,330 --> 00:04:10,960 But it wasn't able to do that because the 29 50s or older switches so to resolve this let's configure 38 00:04:11,230 --> 00:04:27,680 the twenty nine fifty four or two negotiation so if zero is 1 the interface speed or the Duplaix water 39 00:04:29,470 --> 00:04:33,600 interface has gone down hopefully it will come up. 40 00:04:35,430 --> 00:04:38,520 And hopefully they'll be able to negotiate successfully. 41 00:04:38,880 --> 00:04:45,210 So thirty seven fifty is showing up 29 50 showing up show interface. 42 00:04:45,300 --> 00:04:50,630 EF 1 0 3 full duplex 100 make. 43 00:04:51,030 --> 00:05:02,620 So that side is 100 make full duplex to show interface f 0 1 on the site full duplex 100 make. 44 00:05:02,650 --> 00:05:04,930 So they've negotiated successfully. 45 00:05:04,930 --> 00:05:13,490 So moral of the story is either configure both sides for negotiation or hard code both sides generally 46 00:05:13,490 --> 00:05:17,930 today you're going to allow both sides to want to negotiate. 47 00:05:17,930 --> 00:05:25,990 Show run interface if 1 0 1 show run into face. 48 00:05:26,020 --> 00:05:29,030 EF 1 0 1. 49 00:05:29,170 --> 00:05:38,050 Now this is the link between the two thirty seven fifties if one is 0 or 1 the interfaces and currently 50 00:05:38,050 --> 00:05:38,860 connected. 51 00:05:38,860 --> 00:05:41,240 So we've got one interface. 52 00:05:41,240 --> 00:05:50,290 If 1 0 1 between the 2:37 fifties one site is not set for speed and duplex It's set for Orta the other 53 00:05:50,290 --> 00:05:53,150 side is using one hundred Hauffe. 54 00:05:53,170 --> 00:05:54,070 But in this case 55 00:05:58,180 --> 00:06:03,450 the site set for negotiation has reverted to 100 make half duplex. 56 00:06:03,750 --> 00:06:05,210 So that's worked out OK. 57 00:06:05,280 --> 00:06:15,250 In this example However if I change this to have a duplex or full the negotiation will probably fail 58 00:06:15,820 --> 00:06:23,230 and we'll have a duplex mismatch interfaces of come up. 59 00:06:23,320 --> 00:06:24,610 Let's see what it's done. 60 00:06:27,030 --> 00:06:29,130 In this example it's negotiated correctly. 61 00:06:29,190 --> 00:06:34,990 Full duplex 100 make the site do show interface 1 0 1 62 00:06:39,420 --> 00:06:41,250 full duplex 100 meg. 63 00:06:41,250 --> 00:06:47,780 So we manually configured the site with speed and duplex. 64 00:06:47,950 --> 00:06:48,700 The site 65 00:06:51,460 --> 00:06:57,780 has been able to work out what the speed and duplex should be. 66 00:06:57,800 --> 00:07:04,280 So let's set the speed to 10 and the duplex to have 67 00:07:08,150 --> 00:07:11,530 and let's see if the switches can successfully negotiate that. 68 00:07:11,530 --> 00:07:20,900 So interfaces come up show interface if one does 0 1 and I'll simply include the duplex so we don't 69 00:07:20,900 --> 00:07:22,460 see all the output. 70 00:07:22,460 --> 00:07:27,830 Notice how it's negotiated properly so on this switch 71 00:07:30,480 --> 00:07:37,170 it's been manually configured for half duplex 10 meg and the switch has successfully negotiated that. 72 00:07:37,380 --> 00:07:42,900 If I change the duplex here to full Let's see what happens. 73 00:07:42,900 --> 00:07:51,120 Now when the interface comes up so here it's 10 meg full duplex on the side it's also 10 make full duplex 74 00:07:51,810 --> 00:07:58,010 so the thirty seven fifty's are negotiating correctly without any problems. 75 00:07:58,320 --> 00:08:05,880 But that wasn't happening between a 37 50 and a 29 50. 76 00:08:05,910 --> 00:08:07,560 So let's set the speed to 100 77 00:08:11,430 --> 00:08:17,530 so show interface and look at the duplex that's been set. 78 00:08:17,550 --> 00:08:24,710 Try that again 100 full duplex the side 100 full duplex. 79 00:08:24,750 --> 00:08:30,880 So in this case when I set the one side it successfully negotiating with the other side. 80 00:08:31,350 --> 00:08:36,000 But we had problems with negotiation between the 37 50 and 29 50. 81 00:08:36,000 --> 00:08:43,290 So generally the moral of the story is what to negotiation on both sides or hard code on both sides. 82 00:08:43,290 --> 00:08:46,620 Mixing and matching can cause problems. 83 00:08:46,710 --> 00:08:53,580 Today the general recommendation is use auto everywhere except perhaps between called links where you 84 00:08:53,580 --> 00:08:58,080 want to hard code both sides to increase the speed of that interface. 85 00:08:58,080 --> 00:08:58,650 Coming up.