1
00:00:00,180 --> 00:00:04,390
Class C addresses start with binary 110.

2
00:00:04,410 --> 00:00:12,000
So once again, this is not 110 in decimal, but 110 in binary.

3
00:00:12,210 --> 00:00:17,730
The zero in this case is in the third but position in the first octet.

4
00:00:17,880 --> 00:00:26,400
So Class A had zero in the first but position Class B in the second, and now Class C has the zero in

5
00:00:26,400 --> 00:00:27,060
the third.

6
00:00:27,060 --> 00:00:35,340
But position going through the combinations in the first octet will give us a range of 192 to 2 to three.

7
00:00:35,580 --> 00:00:38,970
So this is the range of class C addresses.

8
00:00:39,300 --> 00:00:41,310
In Class C addresses.

9
00:00:41,310 --> 00:00:46,860
The first 24 bits is network, the last eight bits is host.

10
00:00:47,250 --> 00:00:56,910
So for an address of 192.1681.1, we know that this is a class C address because the first octet is

11
00:00:56,910 --> 00:01:00,120
in the range 1922223.

12
00:01:00,270 --> 00:01:07,290
So we have a class C address, which means that the first 24 bits is network and the last eight bits

13
00:01:07,290 --> 00:01:10,800
or octet is the host portion of the address.

14
00:01:11,010 --> 00:01:17,640
So in other words, just by looking at an address, you'll now be able to determine if it's class A,

15
00:01:17,670 --> 00:01:22,650
Class B and Class C based on the ranges we've now discussed.

16
00:01:22,650 --> 00:01:27,870
You'll also be able to know which portion is network and which portion is host.

17
00:01:27,870 --> 00:01:29,130
But be careful.

18
00:01:29,130 --> 00:01:34,920
As mentioned, these classes have been superseded by CIDR or C IDR.

19
00:01:35,220 --> 00:01:44,310
Now Class D addresses are different to Class A, B and C, class A, B and C are used for unicast traffic.

20
00:01:44,310 --> 00:01:47,670
Class D addresses are used for multicast traffic.

21
00:01:47,820 --> 00:01:53,880
Now, with multicast addresses in the first octet, the zero is in the fourth position.

22
00:01:54,360 --> 00:02:02,190
So in these addresses, the first three binary bits are set to one, followed by a binary zero.

23
00:02:02,340 --> 00:02:09,630
Going through all the combinations, the range is from two to 4 to 239 in the first octet.

24
00:02:09,870 --> 00:02:15,510
So this is the range of multicast addresses in IP version four.

25
00:02:15,540 --> 00:02:25,470
So as an example, address to 39.1, 1.1 is a private multicast address which could be used internally

26
00:02:25,470 --> 00:02:27,030
within your organization.

27
00:02:27,480 --> 00:02:34,680
Other examples of multicast addresses include well known multicast addresses for routing protocols such

28
00:02:34,680 --> 00:02:35,760
as OSPF.

29
00:02:36,090 --> 00:02:45,720
The OSPF routing protocol uses multi costs 224.0.0.5 and 224.0.0.6.

30
00:02:46,080 --> 00:02:54,480
These multi costs in the 2 to 4 range are known as link local multi costs, as these multi costs do

31
00:02:54,480 --> 00:02:59,280
not propagate off the local link or local segment.

32
00:02:59,370 --> 00:03:06,870
And multi costs in this range are often used by running protocols such as OSPF, RDP and others.

33
00:03:07,080 --> 00:03:16,620
A multicast implies once again that one device is talking to a group of devices rather than 1 to 1 communication

34
00:03:17,190 --> 00:03:17,730
class.

35
00:03:17,730 --> 00:03:20,820
E addresses are reserved addresses.

36
00:03:20,820 --> 00:03:31,240
They start with four binary ones and on the range two 40.02020 all the way to 255 to 50 5 to 50 5 to

37
00:03:31,240 --> 00:03:35,130
55, which is a reserved address for broadcasts.

38
00:03:35,130 --> 00:03:37,530
We'll talk about broadcasts in a moment.

39
00:03:37,530 --> 00:03:44,970
But once again, the important piece to understand here is that Class E addresses on the range 240 to

40
00:03:44,970 --> 00:03:53,460
255 in the first octet class E addresses are reserved addresses for both testing and other purposes.

41
00:03:54,000 --> 00:03:59,490
So a Class A address uses the first eight bits as the network portion.

42
00:03:59,640 --> 00:04:03,180
So in a pure class address, the first eight bits are network.

43
00:04:03,180 --> 00:04:06,780
So in this example, we've got network ten 0.0.0.

44
00:04:06,780 --> 00:04:13,560
So that's the network address and we have an IP address of 10.1 or 2.3, which is the address configured

45
00:04:13,560 --> 00:04:14,370
on a host.

46
00:04:14,610 --> 00:04:19,649
So this is the host portion of the address and this is the network portion of the address.

47
00:04:19,740 --> 00:04:26,190
Class E networks are once again in the range 1 to 126 in the first octet.

48
00:04:26,190 --> 00:04:32,760
So if a router such as the one in this picture receives traffic going to an IP address of ten .1.1.1,

49
00:04:33,030 --> 00:04:38,520
the router would know that the host is on Network ten because this is a Class A network.

50
00:04:38,610 --> 00:04:44,820
So in this case, it would route the traffic to the left hand side in the same way if it receives traffic

51
00:04:44,820 --> 00:04:48,210
going to an address of 12.1, point one, point one.

52
00:04:48,360 --> 00:04:54,680
It knows that the host is on Network 12 and it would therefore route the traffic to the right hand side.

53
00:04:54,690 --> 00:04:58,980
This is the reason why two hosts can have the same host portion.

54
00:04:59,190 --> 00:04:59,790
So in this.

55
00:04:59,850 --> 00:05:06,150
Example, the host portion is 1.1.1 because they are on different networks.

56
00:05:06,150 --> 00:05:08,130
The network portion is different.

57
00:05:08,830 --> 00:05:11,670
The Rada can use the clause full network.

58
00:05:11,680 --> 00:05:18,910
In other words, the first octet consisting of ten or 12 to differentiate between multiple networks.

59
00:05:18,910 --> 00:05:25,120
So in this case, it's routing on the first eight bits of the address with Class B networks.

60
00:05:25,120 --> 00:05:28,840
The first eight bits denotes the network portion of the address.

61
00:05:28,840 --> 00:05:32,800
So in this example, one 7 to 16 is the network portion.

62
00:05:32,890 --> 00:05:39,310
So this is the network address and a host may have an address such as 172 16 one or two.

63
00:05:39,310 --> 00:05:42,550
So one or two is the host portion of the address.

64
00:05:43,120 --> 00:05:48,580
Class B networks are in the range 128 to 191 in the first octet.

65
00:05:48,670 --> 00:05:56,860
So in the same way as the previous example, a router can route traffic to an address of 172. 16 1.1

66
00:05:56,860 --> 00:06:03,550
because it knows that the network is 172. 16 and it can therefore route the traffic to the left hand

67
00:06:03,550 --> 00:06:12,700
side traffic going to host one 7 to 17 .1.1 is routed to the right hand side because the network portion

68
00:06:12,700 --> 00:06:22,330
is one 7 to 17, whereas this host with IP address one 72.69 1.1 has the network portion of one 72.16

69
00:06:22,720 --> 00:06:27,370
routers can route correctly once again, even though the host portion is the same.

70
00:06:27,370 --> 00:06:33,310
In other words, in this example it's 1.1, but in this case the network portion is different.

71
00:06:33,310 --> 00:06:35,680
So routing takes place correctly.

72
00:06:35,890 --> 00:06:42,280
The router knows that these two hosts are on separate networks because the network portion is different

73
00:06:42,370 --> 00:06:47,980
and in close see addresses 1921681.0 would be a network address.

74
00:06:48,100 --> 00:06:58,210
A host address would be something like 192.168.1.1 close see addresses on the range 190 22223 in the

75
00:06:58,210 --> 00:06:59,320
first octet.

76
00:06:59,320 --> 00:07:06,790
So once again, there are two devices in this example and they have the same host portion, in other

77
00:07:06,790 --> 00:07:08,320
words, dot one.

78
00:07:08,320 --> 00:07:12,070
But the network portion of these two host addresses is different.

79
00:07:12,220 --> 00:07:16,030
On the left hand side, we have 192.168.1.

80
00:07:16,030 --> 00:07:22,810
And on the right hand side we have 192.168.2 in class C addresses.

81
00:07:22,810 --> 00:07:32,050
The first 24 bits or the first three octets of an address denotes network and the lost octet or lost

82
00:07:32,050 --> 00:07:37,030
eight bits denotes host portion in a class C network.