1
00:00:01,490 --> 00:00:05,180
So in DCP we are marking at least three.

2
00:00:05,250 --> 00:00:10,980
We're using the type of service field in an IP version for header for example but only six bits of the

3
00:00:10,980 --> 00:00:15,920
header are used when the six bits are set to zeros.

4
00:00:15,930 --> 00:00:24,600
That's known as best effort class elect a value still exist so as an example if it's set to this that's

5
00:00:24,630 --> 00:00:28,720
IP precedence or one or class selector one.

6
00:00:28,920 --> 00:00:33,510
But in addition they have what are called assured forwarding classes.

7
00:00:33,780 --> 00:00:39,390
We have a shared forwarding class of one should forwarding class to three and four.

8
00:00:39,630 --> 00:00:46,530
So we have these new classes should forwarding Class 1 two 3 and 4.

9
00:00:46,620 --> 00:00:52,470
This number indicates the first three binary bits in the type of service field but assured forwarding

10
00:00:52,470 --> 00:00:57,270
classes have numbers such as 0 1 2

11
00:01:01,090 --> 00:01:02,190
and 3.

12
00:01:02,410 --> 00:01:07,400
So should forwarding Class 1 actually has three values.

13
00:01:07,730 --> 00:01:27,860
There's a f 1 1 F 1 2 and a f 1 3 so the first 3 binary bits gives you your class so a f 1.

14
00:01:27,860 --> 00:01:35,270
The second two binary bits gives you the second number and this is known as the drop a probability.

15
00:01:35,450 --> 00:01:40,850
How probable is it that your traffic will be dropped within class a f 1.

16
00:01:40,940 --> 00:01:47,240
The higher the number the more likely of your traffic being dropped within this class.

17
00:01:47,570 --> 00:01:53,600
When this congestion and you've set up the right mechanisms this traffic will be dropped first then

18
00:01:53,600 --> 00:01:58,280
this traffic and then that traffic within a should forwarding class to you.

19
00:01:58,280 --> 00:02:03,040
We also have a f to 1 a f to two and a half to three.

20
00:02:03,110 --> 00:02:08,300
The same is true for Class 3 and class for the higher the first number.

21
00:02:08,330 --> 00:02:16,970
The more important your traffic but the higher the second number within a class such as a f 1 1 or f

22
00:02:16,970 --> 00:02:19,070
1 2 F 1 3.

23
00:02:19,070 --> 00:02:23,050
The less important your traffic the more likely that it will be dropped.