1 00:00:08,990 --> 00:00:14,990 This is one of multiple videos discussing a multi area of SPF. 2 00:00:14,990 --> 00:00:20,120 This is both a troubleshooting as well as an explanation of video. 3 00:00:20,330 --> 00:00:27,590 We've been told in this topology that brought of one on the left is not able to ping Rada six on the 4 00:00:27,590 --> 00:00:38,640 right rather one is running G.I. joe p So the command show IP protocols shows us that the only writing 5 00:00:38,640 --> 00:00:50,240 protocol enabled on this Rada is EAI GOP on brought a 6 show IP protocols shows us that 0 SPF is enabled 6 00:00:50,300 --> 00:00:53,510 on rota 6. 7 00:00:53,840 --> 00:01:06,030 We can also see that the router has a loop back address of 6 6 6 6 so quadruple 6 can write a 1 ping 8 00:01:06,210 --> 00:01:10,150 that address and the answer is no pings or failing 9 00:01:14,800 --> 00:01:23,600 all disable IP domain lock up to speed things up and let us to trace to that loop back after the moment 10 00:01:23,600 --> 00:01:25,520 to the trace is going nowhere. 11 00:01:27,980 --> 00:01:39,560 I'll do a debug IP package to see what happens and I'll ping with only one paying to that address so 12 00:01:39,560 --> 00:01:42,480 ping six dot six 266. 13 00:01:42,560 --> 00:01:43,060 Repeat. 14 00:01:43,070 --> 00:01:47,340 1 and let's do that again. 15 00:01:50,500 --> 00:01:54,740 And I'll turn off debugging notice here. 16 00:01:54,740 --> 00:02:00,080 Source one wondered wondered one pinging 66 at 66. 17 00:02:00,230 --> 00:02:06,840 We're told that it's unreadable these other messages or even GOP messages. 18 00:02:06,840 --> 00:02:16,080 The ping is unsuccessful to show IP round shows us that the vector network doesn't exist in the routing 19 00:02:16,080 --> 00:02:18,140 table. 20 00:02:18,300 --> 00:02:26,100 If we try and ping tendered one to five but one that also fails and sodas tendered one that five to 21 00:02:26,100 --> 00:02:27,810 two. 22 00:02:28,110 --> 00:02:34,350 So we can't paying this network all the loop back of wrought a six. 23 00:02:34,360 --> 00:02:36,140 What about the loop back of wrought a five. 24 00:02:36,790 --> 00:02:41,260 So we able to ping the loop back around a five but not the loop back about a six. 25 00:02:41,290 --> 00:02:49,540 And if we trace to tendered wondered five that one the trace fails immediately because the right doesn't 26 00:02:49,540 --> 00:02:57,250 exist in the routing table tendered one dot 4.0 does exist in the routing table so we can paying tendered 27 00:02:57,250 --> 00:03:00,990 wondered for that one as well as tendered wondered forward to. 28 00:03:01,180 --> 00:03:04,740 In other words we can get to this network. 29 00:03:05,050 --> 00:03:13,480 Now again we are running EAI GOP on this router so these rorts have been redistributed from USPS into 30 00:03:13,480 --> 00:03:22,680 EAI GOP let's look at right it too and see if wrote too can ping the loop back of Roorda 6. 31 00:03:22,870 --> 00:03:24,400 It's not able to do that. 32 00:03:25,550 --> 00:03:27,520 So show IP ranch. 33 00:03:27,520 --> 00:03:37,600 We are not seeing that looped back in the routing table so let's have a look at what 5 Ken wrote a 5 34 00:03:39,550 --> 00:03:42,520 paying the loop back of road 6. 35 00:03:42,520 --> 00:03:43,860 The answer is it can. 36 00:03:43,870 --> 00:03:51,940 So show IP wrote it's able to ping the loop back around a 6 the loop back exists as an OSP front in 37 00:03:52,000 --> 00:03:54,130 the writing table of route of 5. 38 00:03:54,130 --> 00:03:55,270 What about brought a 4 39 00:03:58,200 --> 00:04:04,230 paying loop back of wrote a 6 that ping fails. 40 00:04:04,230 --> 00:04:10,880 Show IP round back to loop packet doesn't exist in the writing table. 41 00:04:11,270 --> 00:04:19,280 So let's have a look at route of 5 by using the command show IP protocols and tell me if you can see 42 00:04:19,280 --> 00:04:23,350 the problem by looking at this output. 43 00:04:23,400 --> 00:04:26,010 What do you think is the problem when you look at the sound. 44 00:04:26,010 --> 00:04:28,910 Put and to give you a hint. 45 00:04:29,030 --> 00:04:36,810 I'll do the same command on en route for show IP protocols en route a full there's the output for a 46 00:04:36,830 --> 00:04:41,460 for yes the output for road of 5. 47 00:04:41,490 --> 00:04:48,010 What's the problem with this configuration okay. 48 00:04:48,020 --> 00:04:58,300 So notice the following its routing for areas of 1 and 2 the strata has interfaces in multiple areas 49 00:04:58,750 --> 00:05:09,020 but doesn't have area 0 configured so show run Section 0 SPF shows us that the router is configured 50 00:05:09,020 --> 00:05:14,570 for area 1 and area 2 but is not configured for area 0. 51 00:05:15,880 --> 00:05:28,000 Router 4 is configured for Area 1 it's a requirement in 0 SPF that area 0 be connected to other areas. 52 00:05:28,000 --> 00:05:37,800 In other words this is configured as Area 1 This is configured as Area 2 but Area 2 is not adjacent 53 00:05:38,040 --> 00:05:41,180 or bordering area 0. 54 00:05:41,220 --> 00:05:46,780 That's a problem if we look at router 3 over here. 55 00:05:46,780 --> 00:05:57,780 Show IP protocols we can see that this Rada is configured as an area border router it has interfaces 56 00:05:57,780 --> 00:06:09,360 an area 0 and interfaces in Area 1 to show IP SPF interface brief shows us that gigabit 00 is configured 57 00:06:09,360 --> 00:06:19,110 in area 0 gigabit 0 1 is configured in Area 1 so that looks good but rather 5 isn't configured in that 58 00:06:19,110 --> 00:06:20,030 way. 59 00:06:20,220 --> 00:06:23,910 So show IP SPF interface brief. 60 00:06:23,910 --> 00:06:31,030 Notice it has interfaces in Area 1 and Area 2 but not in area 0. 61 00:06:32,160 --> 00:06:42,360 That's why write a 1 campaign the loop back of route of 4 and the loop back of route of 5 but not the 62 00:06:42,360 --> 00:06:45,730 loop back of road a 6 because 63 00:06:48,790 --> 00:06:55,800 SPF is correctly configured with area 0 and Area 1 Over here. 64 00:06:55,890 --> 00:06:59,290 It works but here we have a problem. 65 00:06:59,520 --> 00:07:08,810 We need to create what's called a virtual link between Rider 3 and route of 5. 66 00:07:08,810 --> 00:07:19,610 So we have to essentially pull or extend area 0 from Rider 3 to write a 5 to make road a 5 an area of 67 00:07:19,610 --> 00:07:30,200 border rider so we will be essentially creating a tunnel where area 0 traverses a cross Area 1 2 write 68 00:07:30,200 --> 00:07:38,520 a 5 area zero is going to be tunneled across Area 1 so that route of 5 becomes an area border rider 69 00:07:39,390 --> 00:07:47,350 which means that area 2 is adjacent to area 0 that is required in 0 SPF. 70 00:07:47,520 --> 00:07:58,290 All areas have to be adjacent to area 0 when you have multiple SPF areas so show run section of SPF. 71 00:07:58,380 --> 00:08:02,970 We can see the configuration of Road 3. 72 00:08:03,070 --> 00:08:12,550 Now when you create your virtual links you have to configure the other side using the Rada I.D. not 73 00:08:12,640 --> 00:08:21,760 the IP address of the rota but the Rada I.D. So the command show IP SPF interface will show us the local 74 00:08:21,760 --> 00:08:28,850 routers Rada I.D. So the right I.D. is 3D or tree to tree to tree. 75 00:08:29,250 --> 00:08:35,820 You can also use the command show IPO SPF and we'll be able to see that draw to I.D. So notice Rada 76 00:08:35,870 --> 00:08:44,750 I.D. 3.0 3 2 3 2 3 on route 5 show IP 0 SPF. 77 00:08:45,260 --> 00:08:46,930 The right idea is 5.5. 78 00:08:46,920 --> 00:08:54,160 At 5.5 so background brought a 3 show run Section 0 SPF 79 00:08:56,810 --> 00:09:08,160 that's the configuration of SPF on Route 3 and that's the configuration of wrought a five some road 80 00:09:08,160 --> 00:09:11,420 a three Roorda or SPF. 81 00:09:11,470 --> 00:09:14,520 One area one. 82 00:09:14,650 --> 00:09:24,970 This is the area that we are traversing the virtual link and the neighbors Roorda I.D. is 5 to 5 at 83 00:09:24,970 --> 00:09:26,650 5.5. 84 00:09:26,650 --> 00:09:30,610 Now there are options where you can set authentication and other options. 85 00:09:30,610 --> 00:09:31,670 I'm not going to do that. 86 00:09:31,690 --> 00:09:45,090 I'm simply going to create the virtual link so Roorda SPF 1 area 1 the virtual link and the right I.D. 87 00:09:45,090 --> 00:09:50,190 that will connect to on this side is 3 to 3 2 or 3 2 or 3. 88 00:09:50,250 --> 00:10:00,050 So show IP or SPF neighbor you can see that a neighbor relationship was established using virtual link 89 00:10:00,890 --> 00:10:04,430 0 we can see that over here. 90 00:10:04,670 --> 00:10:13,320 No election takes place on a virtual link show IP or SPF neighbor on the side we can see something similar 91 00:10:13,860 --> 00:10:22,530 a neighbor relationship has been formed from Brother 3 directly to RADA 5 through the 0 SPF virtual 92 00:10:22,530 --> 00:10:23,610 link. 93 00:10:23,610 --> 00:10:30,600 So logically it's as if these two riders rather three and Rod of five are connected to one another so 94 00:10:30,630 --> 00:10:35,610 Ken wrote a three paying the loop back of wrote a six. 95 00:10:35,610 --> 00:10:42,330 Notice the raft is in the writing table so that looks better and notice a rather three can ping the 96 00:10:42,330 --> 00:10:44,860 loot back of a a six. 97 00:10:45,120 --> 00:10:55,000 And if we go back to write a one write a one can now ping the loop back of wrought a six and when we 98 00:10:55,000 --> 00:11:06,850 do a trace notice it goes to Rod to Rod a three right a four rod of five and wrote a six. 99 00:11:06,850 --> 00:11:15,940 This tunnel is not like a Geo re tunnel it's a no SPF mechanism so traffic still goes via the physical 100 00:11:15,940 --> 00:11:24,310 links and you see every hop in the network which you wouldn't see if you were using Jari the virtual 101 00:11:24,310 --> 00:11:28,770 link is simply used for SPF link advertisements. 102 00:11:28,870 --> 00:11:34,080 So in other words to advertise Roth's so we've now solved the problem. 103 00:11:34,230 --> 00:11:42,030 We've been able to configure the network to allow Rod one to ping brought us six let's have a look at 104 00:11:42,030 --> 00:11:51,720 some more information on router 3 so show IP rot we are learning about that network as an into area 105 00:11:51,930 --> 00:11:53,270 network. 106 00:11:53,280 --> 00:12:00,530 It's coming from a separate area show IP SPF database for area zero. 107 00:12:00,530 --> 00:12:10,980 Notice we have wrought a two rather three and root of five in area zero rather five is shown as DNA. 108 00:12:11,270 --> 00:12:18,080 The neighbour relationship will not age so do not age this neighbour relationship because it's set through 109 00:12:18,110 --> 00:12:28,130 a virtual link so we see rudder link states or LSA type one's net link states or LSA type 2s. 110 00:12:28,380 --> 00:12:39,930 We see summary LSD or LSA type 3s we see something similar for Area 1 and we see external rots in the 111 00:12:39,940 --> 00:12:41,360 0 SPF database 112 00:12:45,870 --> 00:12:53,910 so that was an example of how to configure or SPF of virtual links to solve a problem where you've got 113 00:12:53,970 --> 00:13:01,510 an area separated by a another area which is not area zero you know SPF. 114 00:13:01,530 --> 00:13:04,410 All areas have to touch the backbone area. 115 00:13:04,410 --> 00:13:06,550 In other words area zero. 116 00:13:06,570 --> 00:13:16,430 So here we are extending area zero across Area 1 to meet the OSP f design criteria. 117 00:13:16,650 --> 00:13:20,250 I hope you enjoyed this video if you did please like it. 118 00:13:20,520 --> 00:13:23,480 And please subscribe to my YouTube channel. 119 00:13:23,610 --> 00:13:25,290 I wish you all the very best.