1 00:00:04,560 --> 00:00:09,180 Now in the official cert guide that Wendell wrote he spent a lot of time going over SDI or software 2 00:00:09,180 --> 00:00:10,620 defined access. 3 00:00:10,620 --> 00:00:13,430 Now just software defined could be software defined. 4 00:00:13,430 --> 00:00:14,250 Coffee. 5 00:00:14,340 --> 00:00:19,290 I mean there's so many terms with this word of software defined networking got abused. 6 00:00:19,350 --> 00:00:23,160 We had software defined networking that was open flow and we had software defined networking that was 7 00:00:23,160 --> 00:00:24,000 using API. 8 00:00:24,000 --> 00:00:26,280 We had software defined networking there was overlays. 9 00:00:26,460 --> 00:00:31,410 So we spoke about overlays and under Laser ready basically became software defined whatever you like. 10 00:00:31,410 --> 00:00:39,920 But software defined access or SDK Cisco's solution of changing the way a enterprise network works so 11 00:00:39,930 --> 00:00:45,770 traditionally in an enterprise network we would have spanning tree that causes a whole bunch of issues 12 00:00:45,780 --> 00:00:52,200 because we have to match up you know forwarding of ports to a just IP default gateways causes a whole 13 00:00:52,200 --> 00:00:57,930 lot of issues so we want to do away with spending tree and what we do is we just run writing protocols 14 00:00:57,960 --> 00:00:58,880 everywhere. 15 00:00:58,980 --> 00:01:03,500 So the default gateway of your pieces will be the local access switch. 16 00:01:03,510 --> 00:01:08,970 So the switch on the edge the switch that they connect to rather than a call switch or a distribution 17 00:01:08,970 --> 00:01:12,550 switch we run SPF everywhere or writing protocol everywhere. 18 00:01:12,560 --> 00:01:17,730 So we do away with spanning tree we do away with port blocking that kind of stuff. 19 00:01:17,730 --> 00:01:21,940 But in my experience of the CCMA exam I think it was overkill. 20 00:01:21,990 --> 00:01:28,330 The FDA stuff in the O.C. gee now if I hear otherwise I'll change this course. 21 00:01:28,620 --> 00:01:31,680 But I wouldn't spend too much time on SGA. 22 00:01:31,680 --> 00:01:34,850 Basically the idea is the network gets managers of fabric. 23 00:01:35,070 --> 00:01:41,340 So we have all these writers and switches that are controlled by a controller and then similar to NSX 24 00:01:41,340 --> 00:01:48,540 from the Amway what we do is we building tunnels automatically the X land tunnels once again where we 25 00:01:48,540 --> 00:01:51,030 build an overlay across the underlying network. 26 00:01:51,050 --> 00:01:57,270 So the core underlying network can be fairly basic rather than configuring a whole bunch of Axis lists 27 00:01:57,300 --> 00:02:03,600 on the core devices we can do everything as a policy on the SDK server and then apply a policy on the 28 00:02:03,600 --> 00:02:07,980 network devices and DNA center will basically blast off automatically. 29 00:02:07,980 --> 00:02:12,660 So it will build the excellent tunnels it will apply the policies. 30 00:02:12,840 --> 00:02:19,740 So we have this concept once again of intent based networking and intent is I want to do something but 31 00:02:19,740 --> 00:02:24,410 I don't want to have to explicitly write everything down to make that happen. 32 00:02:24,420 --> 00:02:30,300 So as an example I want to stop PCH talking to PTB in a traditional environment you have to create access 33 00:02:30,300 --> 00:02:36,330 lists that stop those devices from talking to each other but if an intent based scenario and and some 34 00:02:36,330 --> 00:02:42,750 of the other it's controller based implementations I would basically say OK this guy can talk to this 35 00:02:42,750 --> 00:02:45,720 guy put across there so that's all done through. 36 00:02:45,720 --> 00:02:46,890 Give me as an example. 37 00:02:46,890 --> 00:02:51,930 And then that applies a policy to the network that basically stops that. 38 00:02:52,030 --> 00:02:56,310 So you as a network engineer don't have to go and configure access lists manually. 39 00:02:56,310 --> 00:03:02,230 Your intent is to stop this guy talking to this guy and the network just makes that happen automatically. 40 00:03:02,580 --> 00:03:06,730 Which is quite scary in some ways because what happens if it goes wrong. 41 00:03:07,060 --> 00:03:11,890 So the whole idea of this SD n stuff is fantastic and I don't want to blow it out of the water straight 42 00:03:11,890 --> 00:03:16,960 away but just be aware that you should kind of understand what's going on under the hood because what 43 00:03:16,960 --> 00:03:18,060 happens if something goes wrong. 44 00:03:19,270 --> 00:03:22,970 But the principle is we have an underlying network. 45 00:03:23,080 --> 00:03:29,080 Then we put vehicles land tunnels over it which allows us to apply policies on the overlay network rather 46 00:03:29,080 --> 00:03:35,710 than on the underlying network so we can stop this guy talking to this guy much more easily using these 47 00:03:35,710 --> 00:03:41,290 tunnels than to try and have a single access list on an interface of a router that blocks people across 48 00:03:41,290 --> 00:03:42,700 the entire network. 49 00:03:43,030 --> 00:03:49,240 Much better way of doing things it's basically the way it's going so we have a controller that manages 50 00:03:49,240 --> 00:03:53,690 a whole bunch of devices in the enterprise. 51 00:03:53,740 --> 00:04:01,030 Now just stepping back a second third to jump around software defined networking was more for the datacenter 52 00:04:01,530 --> 00:04:06,780 so it was NSX was a fantastic success in the data center. 53 00:04:06,840 --> 00:04:09,830 Cisco have ECI also data center product. 54 00:04:10,050 --> 00:04:11,520 But what about enterprises. 55 00:04:11,610 --> 00:04:19,680 So FDA is an enterprise solution where we take software defined principles and apply it to an enterprise 56 00:04:20,280 --> 00:04:26,050 and we apply policies on that network rather than in a datacenter. 57 00:04:26,070 --> 00:04:30,980 So basically simple things like OK let's get rid of spanning tree. 58 00:04:30,990 --> 00:04:34,080 So we run 0 SPF or writing protocol everywhere. 59 00:04:34,140 --> 00:04:36,780 Everything's layer 3 rather than layer 2. 60 00:04:36,810 --> 00:04:39,740 But you know how do we get this device to talk to this device. 61 00:04:39,810 --> 00:04:44,480 We can apply a policy through a gooey or a management station or a controller. 62 00:04:44,580 --> 00:04:51,420 If you want to use the the right term that applies the policy onto the network without you having to 63 00:04:51,420 --> 00:04:53,680 manually configure a whole bunch of stuff. 64 00:04:53,700 --> 00:05:00,630 The idea is use is this term of abstraction abstraction is used everywhere as an example if I want to 65 00:05:00,630 --> 00:05:02,430 write a piece of Python code. 66 00:05:02,430 --> 00:05:07,130 I don't have to know how to make that do something on a hard drive. 67 00:05:07,170 --> 00:05:14,130 I'm an abstracted from a low level programming the operating system abstracts me from the hardware operating 68 00:05:14,130 --> 00:05:20,580 system abstracts me from network cable stuff like that I'm programming in a high level programming language 69 00:05:20,580 --> 00:05:27,810 Python that goes all the way down through the stack and actually make something happen something happen 70 00:05:27,840 --> 00:05:29,570 on the network. 71 00:05:29,640 --> 00:05:35,870 So I'm extracted from assembly language as an example I'm abstracted from low level stuff. 72 00:05:36,030 --> 00:05:40,380 I use my brain for doing high level stuff rather than low level stuff. 73 00:05:40,770 --> 00:05:48,820 So very real world example pilots a pilot today doesn't fly from the UK to the US manually the whole 74 00:05:48,830 --> 00:05:49,490 way. 75 00:05:49,770 --> 00:05:51,960 What do they use they use autopilot. 76 00:05:51,960 --> 00:06:00,000 So the idea is autopilot allows the pilot to take care of high level tasks why the low level stuff is 77 00:06:00,000 --> 00:06:02,540 taken care of using autopilot. 78 00:06:02,580 --> 00:06:08,460 Now the aeroplane has all of these sensors that give information about altitude stuff like that and 79 00:06:08,460 --> 00:06:17,400 then the plane can guide the pilot but autopilot can cause problems where the pilot tries to manage 80 00:06:17,400 --> 00:06:23,760 the network or should I say the plane through autopilot by adjusting various high level parameters rather 81 00:06:23,760 --> 00:06:26,260 than just grabbing the plane and flying it. 82 00:06:26,410 --> 00:06:31,800 And it was a really interesting video where they were talking about this issue where automation has 83 00:06:31,800 --> 00:06:38,790 actually caused the crashes because pilots no longer fly the plane like physically fly it they try and 84 00:06:38,790 --> 00:06:45,450 adjust the planes flying through autopilot so that they try and feed information to autopilot that then 85 00:06:45,450 --> 00:06:47,520 flies the plane and adjusts adjusts the plane. 86 00:06:47,870 --> 00:06:54,210 But if you got a plane flying at you you as a pilot you'd grab the aeroplane and fly it out of the way 87 00:06:54,210 --> 00:06:56,500 rather than trying to adjust autopilot. 88 00:06:56,550 --> 00:07:00,780 And I think that's the same thing that we as network engineers need to be careful of is don't rely on 89 00:07:00,780 --> 00:07:08,610 the autopilot or the cleverness of all of these applications when the network is burning or there's 90 00:07:08,640 --> 00:07:12,040 a fire you need to jump in and fix the problems. 91 00:07:12,090 --> 00:07:17,580 So automation has its place but it's still important to understand how networks work because automation 92 00:07:17,580 --> 00:07:24,160 will allow you to break a network very very quickly if you don't understand what automation is doing. 93 00:07:24,180 --> 00:07:30,530 I mean if a programmer just writes a script that sends a whole bunch of BP to use it to a network running 94 00:07:30,530 --> 00:07:33,200 spending tree it could mess up your whole network. 95 00:07:33,210 --> 00:07:38,210 So you need to understand what your program is doing what these applications are doing. 96 00:07:38,310 --> 00:07:43,980 So there's huge advantages to abstraction huge advantages to automation but you still need to understand 97 00:07:43,980 --> 00:07:44,850 networking. 98 00:07:44,880 --> 00:07:46,870 So I think Cisco has done a good thing here. 99 00:07:46,880 --> 00:07:53,850 Ten percent of the CCMA is automation and programming or program ability 90 percent is a lot of traditional 100 00:07:53,850 --> 00:07:58,860 network stuff useful and network person is still a network engineer you still need to understand protocols 101 00:07:58,860 --> 00:08:07,020 like spending 3 0 SPF etc. But I think for me the programming side is very exciting because Cisco now 102 00:08:07,020 --> 00:08:13,450 have this definite track so you have this world in front of you which didn't exist. 103 00:08:13,530 --> 00:08:18,480 I'm recording this you know not long after the CCMA was released. 104 00:08:18,480 --> 00:08:25,260 You've got this world now where you can go traditional networking with a bit of programming or you can 105 00:08:25,260 --> 00:08:27,670 go programming with a bit of networking. 106 00:08:27,690 --> 00:08:32,910 So I think if you starting in your career you have two wonderful choices and I mean you just got to 107 00:08:32,910 --> 00:08:37,560 decide what you enjoy do you enjoy programming with a touch of networking or do you enjoy networking 108 00:08:37,560 --> 00:08:38,880 with a touch of programming. 109 00:08:38,880 --> 00:08:42,570 I think those are going to actually become closer and close in future. 110 00:08:42,570 --> 00:08:49,140 So five 10 years from today the line between networking and programming will just draw closer and closer. 111 00:08:49,140 --> 00:08:51,900 Networking is changing and I've been saying this for many years. 112 00:08:51,930 --> 00:08:53,930 I mean now we are going more to the cloud. 113 00:08:53,940 --> 00:08:56,560 So cloud stuff is becoming more important. 114 00:08:56,700 --> 00:09:00,890 But don't think that if you put it in the cloud it's going to solve your network problems. 115 00:09:00,910 --> 00:09:01,780 It's still a network. 116 00:09:01,780 --> 00:09:05,500 You still have to manage the network cloud as in your network. 117 00:09:05,980 --> 00:09:09,020 I mean if you put a VM in the cloud it's cool it's just a VM. 118 00:09:09,130 --> 00:09:14,210 But what happens if you have virtual machines in Asia and in America and in Europe. 119 00:09:14,290 --> 00:09:18,610 Suddenly you start working with low balances you start working with firewalls you start working with 120 00:09:18,640 --> 00:09:24,040 access control lists you start working with villains not call that but you start working with all the 121 00:09:24,040 --> 00:09:25,530 traditional networking stuff. 122 00:09:25,600 --> 00:09:29,440 So just because it's in the cloud doesn't mean that you can ignore networking still gonna be a lot of 123 00:09:29,440 --> 00:09:31,530 work for network engineers. 124 00:09:31,570 --> 00:09:35,340 It's just the roles may change rather than typing on the CLIA. 125 00:09:35,350 --> 00:09:41,800 You might be working in a controller or in the cloud but you still need to understand networking principles. 126 00:09:41,860 --> 00:09:48,340 Okay so that was quite a long ramble a hope that kind of discussion was valuable to add to the course. 127 00:09:48,430 --> 00:09:57,190 I'm going to show you some more practical stuff now in the rest of the course but hopefully that gives 128 00:09:57,190 --> 00:10:03,880 you a good idea of what's important for the exam and kind of sets the 10000 foot view and overview of 129 00:10:03,880 --> 00:10:06,190 programming and network automation.