1 00:00:01,030 --> 00:00:04,150 So what is the Cisco quality of service toolset? 2 00:00:04,540 --> 00:00:12,460 The R&D guide discusses the following mechanisms or quality of service tool sets that allow you to implement 3 00:00:12,460 --> 00:00:13,750 quality of service. 4 00:00:13,960 --> 00:00:18,490 This is what is emphasized in the Q&A exam. 5 00:00:19,000 --> 00:00:27,340 The exam talks about marking device trust, prioritization, shaping policing and congestion management. 6 00:00:27,730 --> 00:00:35,890 And if you look at the mechanisms listed in the R&D guide, we have classification and marking policing 7 00:00:35,890 --> 00:00:38,410 and markdown scheduling. 8 00:00:38,650 --> 00:00:40,360 Link Specific tools. 9 00:00:41,180 --> 00:00:46,160 And there are some additional options, such as order quotas and call it mission control. 10 00:00:47,340 --> 00:00:50,730 Here's a graphic showing the quality of service tool set. 11 00:00:51,060 --> 00:01:01,050 Now these mechanisms apply to differentiated services or serve into service has its own mechanisms and 12 00:01:01,050 --> 00:01:04,290 best effort to essentially doesn't have these mechanisms. 13 00:01:04,379 --> 00:01:07,920 It simply treats all traffic the same. 14 00:01:08,250 --> 00:01:10,480 Firstly, we have admission control. 15 00:01:10,500 --> 00:01:15,300 Will your call, as an example, be permitted across the IP network? 16 00:01:15,630 --> 00:01:21,660 If there's oversubscription of a link, a voice call may need to take an alternate path. 17 00:01:22,050 --> 00:01:27,840 Classification and marking is essentially looking at traffic types and putting them into classes. 18 00:01:28,110 --> 00:01:29,880 So is it a voice traffic? 19 00:01:29,910 --> 00:01:33,030 If it is, then it goes into a certain class. 20 00:01:33,330 --> 00:01:34,910 Is it a video traffic? 21 00:01:34,920 --> 00:01:37,350 Then it would go into a different class. 22 00:01:37,680 --> 00:01:39,150 Is it FTP? 23 00:01:39,300 --> 00:01:41,490 FTP would go into third class? 24 00:01:41,970 --> 00:01:43,920 We have policing and markdown. 25 00:01:44,040 --> 00:01:50,580 If you're sending too much traffic, your traffic could be dropped or the quality of service given to 26 00:01:50,580 --> 00:01:51,900 you could be lowered. 27 00:01:52,350 --> 00:01:55,800 Then we have scheduling, which includes queuing and dropping. 28 00:01:55,830 --> 00:02:00,240 We have traffic shaping and link specific mechanisms. 29 00:02:01,900 --> 00:02:04,480 We'll start off with classification and marking. 30 00:02:04,900 --> 00:02:13,630 When you send a package with FedEx or DHL, that package needs to be marked for next day delivery or 31 00:02:13,630 --> 00:02:16,600 urgent delivery or standard delivery. 32 00:02:16,960 --> 00:02:24,760 A label gets put onto the package to indicate how important that package is when the package is sent 33 00:02:24,760 --> 00:02:26,740 from one depot to another. 34 00:02:26,890 --> 00:02:32,260 They don't open the package to determine the quality of service that that package would get. 35 00:02:32,620 --> 00:02:39,250 They look at the label and the label determines the quality of service that the package gets. 36 00:02:39,700 --> 00:02:43,780 In the same way, when a telephone sends packets into a network. 37 00:02:43,810 --> 00:02:51,670 It needs to mark those packets as important so that every switch and router along the path can treat 38 00:02:51,670 --> 00:02:56,680 the packet differently when compared to, say, FTP sent by a PC. 39 00:02:57,720 --> 00:03:04,890 So when packets are forwarded from the phone to the first switch, it needs to indicate using some kind 40 00:03:04,890 --> 00:03:09,690 of marking or label or field that the packet is important. 41 00:03:09,720 --> 00:03:14,100 It needs to be treated better than, say, an FTP packet. 42 00:03:14,370 --> 00:03:20,460 When switch one sends the packet to switch two, it needs to indicate to that switch that the packet 43 00:03:20,460 --> 00:03:21,420 is important. 44 00:03:21,570 --> 00:03:27,540 And in the same way, when the second switch sends the packet to the router, it needs to indicate to 45 00:03:27,540 --> 00:03:30,540 the broader that the packet is of great importance. 46 00:03:30,840 --> 00:03:33,930 Now this introduces the concept of a trust boundary. 47 00:03:34,020 --> 00:03:36,300 Who do we trust in the network? 48 00:03:36,690 --> 00:03:43,680 As an example, does the router trust switch to the switch to trust switch one as an example. 49 00:03:44,010 --> 00:03:50,970 If these devices trust the markings that they receive from each other or the quality of service settings 50 00:03:50,970 --> 00:03:55,290 that they receive from one another, then the trust boundary ends over here. 51 00:03:55,830 --> 00:04:01,950 In other words, the switch doesn't trust the phone and the switch doesn't trust the PC. 52 00:04:02,580 --> 00:04:03,810 If, however. 53 00:04:04,500 --> 00:04:06,510 The switch did trust the phone. 54 00:04:06,540 --> 00:04:13,380 The trust boundary would be extended to the phone, as is the case with a lot of IP phones. 55 00:04:13,590 --> 00:04:17,550 We could have a PC connected to a phone. 56 00:04:18,200 --> 00:04:24,500 So we could connect the PC to the back of the phone, and in that case, the trust boundary would end 57 00:04:24,500 --> 00:04:25,430 at the phone. 58 00:04:25,700 --> 00:04:31,860 In other words, the switches and the router trust the phone, but they don't trust the PC. 59 00:04:31,910 --> 00:04:38,570 So if the PC sends traffic to the phone, telling the phone that its traffic is important, the phone 60 00:04:38,570 --> 00:04:44,440 will not trust those markings, all those values, and would override them in the same way. 61 00:04:44,450 --> 00:04:51,140 Switch one doesn't trust the markings or values sent by the PC, but it would trust the markings or 62 00:04:51,140 --> 00:04:53,150 values sent by the phone. 63 00:04:53,510 --> 00:04:59,090 And again, switch two would trust what switch one tells it and the writer would trust switch to. 64 00:04:59,570 --> 00:05:06,580 As an analogy, if you go to the airport and your ticket says that you have a first class ticket, you 65 00:05:06,590 --> 00:05:12,590 will be treated differently to someone who has a economy class ticket. 66 00:05:12,770 --> 00:05:17,320 But the people at the airport won't accept a ticket that you've just made up. 67 00:05:17,330 --> 00:05:22,430 So if you just printed out your own ticket, they're not going to trust that unless they can reference 68 00:05:22,430 --> 00:05:23,360 it officially.