1
00:00:14,350 --> 00:00:20,150
This is one of multiple videos discussing static routing.

2
00:00:20,350 --> 00:00:28,110
So notice what happens now when we configure a default route to 10 1 1 1.

3
00:00:28,750 --> 00:00:38,100
But specify an admin distance of say 100 and that should be the next top product 10 1 1 2 with an admin

4
00:00:38,100 --> 00:00:39,470
distance of 100.

5
00:00:39,540 --> 00:00:42,140
So do show IP raat.

6
00:00:42,370 --> 00:00:44,590
We've got a raft in the drawing table.

7
00:00:44,890 --> 00:00:49,510
Notice the admin distance is 100 whereas previously

8
00:00:52,400 --> 00:00:55,490
the admin distances of the Roths was 1.

9
00:00:56,000 --> 00:01:04,540
So one shown here the router can ping the loopback of Rodda five.

10
00:01:04,800 --> 00:01:11,250
And when we trace to the loopback it's going via Rodek to.

11
00:01:11,490 --> 00:01:16,700
And that should be expected because that's the route that we have in the running table.

12
00:01:17,950 --> 00:01:26,530
What happens when we add a static route to router 3 but with an admin distance of 150 and let's add

13
00:01:27,180 --> 00:01:35,820
Rodda 4 with an admin distance of 200 What do you think the running table is going to look like.

14
00:01:35,830 --> 00:01:41,290
So show IP route only shows the route to brought it to you.

15
00:01:41,740 --> 00:01:45,680
And that's because it's got to the lowest at Ministry of distance.

16
00:01:45,790 --> 00:01:57,710
So when we trace to the loopback of route of 5 it's going via Radha to the running config shows us that

17
00:01:57,710 --> 00:02:00,710
there are three routes in the running config.

18
00:02:01,220 --> 00:02:11,220
So this is a way to implement a preferred path which is route to and then a backup path and a second

19
00:02:11,220 --> 00:02:14,520
backup.

20
00:02:14,880 --> 00:02:22,140
What will happen now is rodder will be used as the primary path because that's the only road in the

21
00:02:22,140 --> 00:02:23,230
writing table.

22
00:02:23,550 --> 00:02:31,430
But when we shut down an interface down cell shut down gigabit 00 the link to rodded to we can see the

23
00:02:31,430 --> 00:02:32,660
interface has gone down.

24
00:02:33,840 --> 00:02:35,370
When we top show IP route.

25
00:02:35,420 --> 00:02:45,600
Notice the raft has changed to go to 10 1 to 2 has a higher Ministry of distance but thats a lower than

26
00:02:45,600 --> 00:02:47,860
the ministry of distance via radio 4.

27
00:02:48,060 --> 00:03:01,500
So now traffic it goes via router 3 again in the running config weve got three routes and this route

28
00:03:01,530 --> 00:03:03,820
is the route being used at the moment.

29
00:03:05,030 --> 00:03:14,510
Because the linkage to the next top route it is down because the interface is massively down.

30
00:03:14,830 --> 00:03:22,570
So the Rodek can see that this IP address is an interface that's down and that IP addresses in the same

31
00:03:22,570 --> 00:03:24,700
subnet as the IP address.

32
00:03:24,700 --> 00:03:28,650
So that route is removed from the writing table.

33
00:03:28,840 --> 00:03:32,420
And this route is put in to the writing table.

34
00:03:32,440 --> 00:03:38,710
So again the static route via 10 1 to 2 is in the writing table.

35
00:03:38,710 --> 00:03:41,830
Now if we shut gigabit the zero or one down

36
00:03:44,550 --> 00:03:52,050
what we should see is that the third route appears in the writing table and it does traffic is now going

37
00:03:52,050 --> 00:04:02,340
to go via Rodda for what it does it goes to 10 1 3 2 and then on to write a five.

38
00:04:02,350 --> 00:04:11,870
So again we can still paying the loopback of wrote a 5 but the traffic is taking a different path.

39
00:04:11,890 --> 00:04:15,090
Notice the admission of distance of this road is two hundred.

40
00:04:15,160 --> 00:04:20,120
The next top is 10 1 3 2.

41
00:04:20,180 --> 00:04:23,480
So we now know Schutt gigabit 0 1.

42
00:04:23,480 --> 00:04:31,910
In other words enable that interface what we should see is that the path changes and it has it's now

43
00:04:31,910 --> 00:04:38,040
going via 10 1 to 2 because that has a lot of distance.

44
00:04:38,240 --> 00:04:40,820
And if we know Shatru gigabit 00

45
00:04:44,890 --> 00:04:52,580
traffic should switch back to 10 1 1 to which it has so administered distances in this way are often

46
00:04:52,580 --> 00:05:00,740
used to select a primary path backup path and an alternate backup path.

47
00:05:00,740 --> 00:05:03,500
This could be an less link.

48
00:05:03,710 --> 00:05:11,650
This could be a good internet connection and this could be a not so good internet connection.

49
00:05:12,530 --> 00:05:18,590
So we've got three paths to get to our destination and we'll choose the primary path first.

50
00:05:18,650 --> 00:05:26,410
But if it's not available then this path and if that's not available then we'll choose the path M.Tech

51
00:05:26,420 --> 00:05:36,200
routes don't work that well in that they will only be removed from the writing table if the local interface

52
00:05:36,200 --> 00:05:38,020
goes down.

53
00:05:38,080 --> 00:05:45,430
So as an example if I shut down this link traffic would still go via rodded too and would end up in

54
00:05:45,430 --> 00:05:46,990
a black hole.

55
00:05:47,750 --> 00:05:57,530
So as an example all say and a thousand pings to Rodda five before I start that ping

56
00:06:01,090 --> 00:06:04,690
I'll get routed to ready.

57
00:06:05,160 --> 00:06:06,120
So keep it.

58
00:06:06,130 --> 00:06:14,700
0 1 notice we are pinging but if I shut that interface down the pings start failing.

59
00:06:14,790 --> 00:06:23,500
We get an unreachable message wrote a one configured restudy Grotz doesn't realize that there's a problem

60
00:06:24,910 --> 00:06:26,690
elsewhere in the network.

61
00:06:26,800 --> 00:06:34,650
So it's still forwarding traffic to 10 1 1 2 even though that link is down wrote it to in this case

62
00:06:34,650 --> 00:06:37,350
is running a running protocol.

63
00:06:37,590 --> 00:06:44,310
So it can dynamically change its behavior but a broad with steady growth doesn't do that.

64
00:06:45,950 --> 00:06:52,290
And that's a reason why you run dynamic writing protocols.

65
00:06:52,440 --> 00:07:00,930
So when the interface came up again Rodda one was able to ping wrote a five start that again and shut

66
00:07:00,930 --> 00:07:01,820
the interface down.

67
00:07:01,820 --> 00:07:09,560
Now it doesn't dynamically shift traffic to an alternate path.

68
00:07:10,940 --> 00:07:12,980
So that is a disadvantage of steady growth.

69
00:07:15,300 --> 00:07:22,370
They are static by nature they don't dynamically change based on network conditions.

70
00:07:22,560 --> 00:07:26,570
They'll only reroute if the local interface goes down.

71
00:07:27,090 --> 00:07:34,120
But if these interfaces are up the road is a way of problems elsewhere in the network.

72
00:07:34,120 --> 00:07:40,080
But if we were running a dynamic routing protocol it would dynamically adjust to network conditions

73
00:07:40,990 --> 00:07:48,160
so dynamic routing protocol such as your job always P.F. and BGP are better than running static routes

74
00:07:48,640 --> 00:07:54,060
when you want your network to dynamically adjust to network conditions.

75
00:07:54,070 --> 00:08:00,490
I you found this video useful if it was of benefit to you please like it and please subscribe to my

76
00:08:00,490 --> 00:08:01,550
YouTube channel.

77
00:08:01,840 --> 00:08:03,680
I wish you all the very best.