1 00:00:08,810 --> 00:00:11,900 This is one of multiple OSPF videos. 2 00:00:12,230 --> 00:00:19,880 I was asked to explain OSPF multiple areas and this is one of multiple videos helping explain how OSPF 3 00:00:19,880 --> 00:00:23,120 works when you have multiple areas configured. 4 00:00:24,180 --> 00:00:26,490 Rather five is another area border. 5 00:00:26,490 --> 00:00:32,729 Rather it exists between area zero and area two. 6 00:00:32,940 --> 00:00:35,820 So bypass the initial configuration dialog. 7 00:00:38,060 --> 00:00:39,600 And I'll configure this as right. 8 00:00:39,650 --> 00:00:42,050 A five interface gigabit. 9 00:00:42,110 --> 00:00:44,720 Zero zero no shut IP address. 10 00:00:44,720 --> 00:00:47,000 Ten 142. 11 00:00:48,770 --> 00:00:50,270 Slash 24 mosque. 12 00:00:53,630 --> 00:01:00,290 So that was the IP address configured on gigabit zero zero on interface gigabit zero one IP address 13 00:01:00,290 --> 00:01:01,940 ten 151. 14 00:01:03,820 --> 00:01:09,220 Slash 24 musk and I'll create a loopback of quadruple five. 15 00:01:12,020 --> 00:01:13,580 So do show. 16 00:01:14,060 --> 00:01:17,630 IP interface brief. 17 00:01:18,050 --> 00:01:21,410 IP addresses are configured on the various interfaces. 18 00:01:21,410 --> 00:01:24,170 I forgot a no shut gigabit to zero one. 19 00:01:24,170 --> 00:01:25,190 So there we go. 20 00:01:25,550 --> 00:01:31,250 On this Friday we are going to configure OSPF, but what we're going to do now is make sure that we 21 00:01:31,250 --> 00:01:34,310 configure and I'll do it slightly differently now. 22 00:01:34,520 --> 00:01:40,880 We'll configure gigabit zero zero in Area zero. 23 00:01:41,030 --> 00:01:48,320 So we're saying this interface gigabit is zero zero, which has an IP address of ten 142 is going to 24 00:01:48,320 --> 00:01:53,840 be put into area zero because of the mask used here. 25 00:01:53,870 --> 00:01:55,430 It's an inverse mask. 26 00:01:56,030 --> 00:02:03,980 I'll also put the loopback of the router into area zero and then I'll configure. 27 00:02:06,910 --> 00:02:07,380 Gigabit. 28 00:02:07,390 --> 00:02:10,000 Is there one in area two. 29 00:02:10,419 --> 00:02:15,490 So show run section OSPF. 30 00:02:16,150 --> 00:02:18,970 That's the configuration of OSPF on the router. 31 00:02:18,970 --> 00:02:21,580 Show IP OSPF interface brief. 32 00:02:22,150 --> 00:02:29,020 At the moment we only have OSPF enabled on one interface and that's because I made some mistakes. 33 00:02:29,020 --> 00:02:31,240 So let's redo that. 34 00:02:32,580 --> 00:02:33,690 No network. 35 00:02:33,690 --> 00:02:35,100 Four, four, four, four. 36 00:02:38,190 --> 00:02:39,450 Should be network. 37 00:02:39,660 --> 00:02:41,340 Five, five, five, five. 38 00:02:44,720 --> 00:02:46,940 Show ip ospf. 39 00:02:49,260 --> 00:02:59,010 Interface brief we've got OSPF running on the loopback and gigabit is zero zero so show IP interface 40 00:02:59,010 --> 00:03:03,690 brief ten 151 is configured on gigabit is zero one. 41 00:03:04,950 --> 00:03:07,770 Let's see what I did wrong in OSPF. 42 00:03:08,400 --> 00:03:10,740 I put this as a zero. 43 00:03:11,040 --> 00:03:14,970 Rather than using the right mosque. 44 00:03:14,970 --> 00:03:18,780 So no network ten 150. 45 00:03:20,430 --> 00:03:22,080 This should have been done. 46 00:03:26,700 --> 00:03:27,600 Like this. 47 00:03:28,260 --> 00:03:32,940 So show IP OSPF interface brief. 48 00:03:33,630 --> 00:03:34,560 That looks better. 49 00:03:34,590 --> 00:03:37,020 OSPF is configured on three interfaces. 50 00:03:37,230 --> 00:03:40,110 Show IP route. 51 00:03:40,110 --> 00:03:48,090 We are learning in area routes, in area routes and external routes. 52 00:03:50,040 --> 00:03:53,520 And rather five should be able to ping rotor one, which it can. 53 00:03:54,160 --> 00:03:56,560 And we can see the output on router one. 54 00:03:57,810 --> 00:03:58,080 Okay. 55 00:03:58,080 --> 00:04:00,690 So the lost router to configure is router six. 56 00:04:00,990 --> 00:04:02,970 This is an internal router. 57 00:04:03,210 --> 00:04:07,560 All interfaces on this router belong to area two. 58 00:04:07,770 --> 00:04:14,190 So bypass the initial configuration dialog and I'll configure the router. 59 00:04:15,480 --> 00:04:22,890 So it should be right of six interface gigabit zero zero no shut IP address ten 152. 60 00:04:25,650 --> 00:04:28,770 So that's the IP address on gigabit zero zero. 61 00:04:30,540 --> 00:04:31,920 Interface loopback zero. 62 00:04:31,950 --> 00:04:34,590 IP address quadruple six. 63 00:04:37,500 --> 00:04:38,580 As follows. 64 00:04:38,730 --> 00:04:46,560 Router ospf one network and I'll just do it this way to keep it simple. 65 00:04:46,590 --> 00:04:51,990 All interfaces in this example belong to area two. 66 00:04:52,770 --> 00:04:56,670 So show IP OSPF interface brief. 67 00:04:58,910 --> 00:05:05,810 Show IP OSPF interface brief shows us that OSPF is running on both gigabits or zero and the loopback 68 00:05:05,840 --> 00:05:13,640 show IP OSPF neighbor shows us our neighbor relationship two out of five show IP route shows us our 69 00:05:13,640 --> 00:05:14,600 routing table. 70 00:05:15,260 --> 00:05:22,550 Now here we don't see any intra area routes because this Ethernet interface and the loopback of the 71 00:05:22,550 --> 00:05:30,200 local router are seen as directly connected rather than being advertised by a writing protocol. 72 00:05:30,740 --> 00:05:37,040 So we see inter area roots and quite a few of them as well as external routes. 73 00:05:37,280 --> 00:05:44,420 Row two six should be able to ping rather one, which it can and we can see the debugger and router 74 00:05:44,420 --> 00:05:44,900 one. 75 00:05:45,260 --> 00:05:48,740 So show IP OSPF database. 76 00:05:49,130 --> 00:05:57,470 Notice that on router six this command shows us only area two because the route is only configured in 77 00:05:57,470 --> 00:05:58,460 area two. 78 00:05:58,550 --> 00:06:02,950 It sees that router six and router five are configured in area two. 79 00:06:02,960 --> 00:06:13,280 It sees that router five is the designated router on the Ethernet segment in area two, it sees a range 80 00:06:13,280 --> 00:06:14,810 of losses. 81 00:06:14,960 --> 00:06:19,250 These are into area routes, LSA Type three. 82 00:06:19,700 --> 00:06:28,520 It sees a type for LSA, which is a summary SBR LSA, and it sees external routes. 83 00:06:28,790 --> 00:06:38,450 So there you have an example of many LSA types that you get in OSPF LSA type one rather less LSA Type 84 00:06:38,480 --> 00:06:41,330 two network link Alice's. 85 00:06:43,840 --> 00:06:51,850 Top three summary lists, type for April essays and top five external essays. 86 00:06:52,150 --> 00:06:57,220 Let's have a look at Root of five, which has interfaces in multiple areas. 87 00:06:57,220 --> 00:07:06,370 So show IP OSPF database, you'll notice it displays information for area zero as well as for area to. 88 00:07:07,040 --> 00:07:16,760 So on Area zero, we have three routers and Area zero, we have two designated routers in Area zero. 89 00:07:17,360 --> 00:07:26,300 So to net the link states, these are summary lists or routes coming from other OSPF areas. 90 00:07:27,390 --> 00:07:29,430 There is one autonomous system. 91 00:07:29,430 --> 00:07:31,110 Border writer Alyssa. 92 00:07:32,340 --> 00:07:39,840 Then we see similar information for Area two and right at the end we see the external losses or less 93 00:07:39,870 --> 00:07:41,010 top five. 94 00:07:41,310 --> 00:07:46,260 That was an example of how to configure multi area OSPF. 95 00:07:47,070 --> 00:07:48,840 I hope you found this video useful. 96 00:07:48,840 --> 00:07:53,640 If it's been of benefit to you, please like it and please subscribe to my YouTube channel. 97 00:07:53,850 --> 00:07:55,800 I wish you all the very best.