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In this video, we're going to discuss arrest APIs or representational state transfer application programming

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interfaces.

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A long name, basically short name, rest APIs.

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Application programming interfaces allow us to get one application to interact with another application.

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As an example, if you want to use the functionality of Google Maps rather than developing your own

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mapping system, you can integrate Google Maps with your application, and then you can send queries

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to Google Maps using an application and then get responses back from Google Maps.

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Rest APIs are used everywhere.

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It's really important that you learn the basics of rest APIs for the CCNA exam.

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You don't have to learn Python.

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You have to have an understanding of a rest APIs and have an understanding of DNA center.

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In this video, however, I'm going to show you how you can interact with a Cisco device using a rest

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API and a Python script.

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So we're going to write a Python script that interacts with the rest API on a Cisco router.

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You once again don't need to learn that for the CCNA exam.

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You would need to know that for the Cisco dev net exam.

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But it's well worth learning the stuff, as I've been saying, for the real world.

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If you want to differentiate yourself from others, it's well worth learning.

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Rest APIs well worth learning.

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Python.

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Now I'm going to cover this section differently to other instructors.

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Too many of them say connect to this dev net server, but they're using a prebuilt application or prebuilt

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information and it's very difficult to replicate what they're doing if you don't download prebuilt stuff

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from Cisco Dev Net, some instructors are simply copying the dev net labs.

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They're not actually doing their own thing.

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So I want to show you this from the ground up.

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I want to show you how you can interact with rest APIs without using prebuilt stuff that's been downloaded.

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I'm going to show you how to download an application called Postman.

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I'm going to show you how you can manually update Postman with IP addresses and other information not

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using prebuilt stuff.

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So I'm going to show you how you can overcome some issues that you will encounter if you do this manually

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rather than using prebuilt stuff.

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There's an issue with certificates.

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As an example, you have to tell Postman to accept a self sign certificates, otherwise it won't interact

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with the devices that are using self signed certificates.

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We're going to manually configure IP addresses rather than once again using prebuilt stuff.

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But to make it easier for you, I've created this entire PowerPoint presentation.

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In this PowerPoint presentation, I've given you the links to Cisco's dev net labs.

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So the definite DNA center always on labs.

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Your URL is here, here is the username and here's the password.

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So you can simply download this PowerPoint presentation and use it all.

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The links are here that I'm using.

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All the information is within this document as an example.

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Here's the API documentation question people often ask is How do I know what APIs to use while there's

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an example of the API documentation for DNA center?

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There's also a definite lab that you can follow if you want to.

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So if you want to go through one of the dev net labs, there is a good example of a dev net lab.

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But what I'm going to show you as an example is how to connect to labs and manually.

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So we're going to use Postman, which is an application.

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I'll show you in a moment how to download.

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It allows you very easily to interact with APIs, allows you to do some basic testing and check for

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issues.

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Really good application for testing APIs.

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So I'm going to show you the URL to connect to you.

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I'll show you how to bypass the issue with self signed certificates.

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You need to turn this off, otherwise you will have problems if you try and connect to some of their

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labs.

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It's not going to work because you need to turn this off.

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Otherwise, Postman by Default rejects the connection.

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All the username and password information is within this document, and I'm showing you step by step

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what to do.

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I'm going to demonstrate it practically using a video, so I'm going to show you how to do this.

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But I've also given you this entire PowerPoint presentation so that you can keep this as reference for

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later.

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I've also included a Python script.

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So this is a very basic Python script that allows me to connect to a Cisco router.

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In this example, we're going to connect to a Cisco router.

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We're going to connect to this router on this port number.

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And then we're going to get a list of interfaces from the router using an API.

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So I really hope this helps you.

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If you follow along in this video, you should get a really good understanding and I'll show you step

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by step how to interact with both DNA center as well as with a XY router, in other words, a Cisco

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router.

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But you can download this PowerPoint presentation and have it as a reference to really help you.

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After you've watched these videos six months from today, you might just want to have this as a reference.

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Okay.

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APIs are used everywhere.

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You probably use them all the time without realizing applications.

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Talk to other applications using application programming interfaces.

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These are becoming more and more important.

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It's very difficult for applications to share information using non structured data.

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In a separate video, I spoke about JSON and how you need to use JSON formatting to share information

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between devices.

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Structured data is really important.

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Having a structured application programming interface is really important if you want machines talking

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to machines.

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He has an example.

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Notice that a lamp I press a button on my phone, it goes off.

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This is a hue lamp.

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It has an exposed API.

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Now because of APIs, I can once again do this.

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Alexa Turn off.

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David Office old big lamp.

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Okay.

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Notice the lamp went off.

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Very simple example of an API.

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Alexa, turn on David.

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Office old, big lamp.

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Okay.

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Alexa So that's an example of one program, talking to another program.

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We've got a hue lamp system, we've got Alexa and they are talking to each other.

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And application programming interfaces allow me to do interesting things like that where I can get one

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device to interact with another device and do something.

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Now you can use SSH to simply SSH to a broader and configure a router.

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The problem is when you type show version or show IP interface brief, that data that's displayed is

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for human consumption.

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In other words, humans will understand the information, but machines will struggle with the information

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that's displayed if the show version command is run on different routers Cisco Nexus, Cisco, iOS,

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classic, iOS, monolithic iOS versus iSCSI.

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The output will be slightly different and machines will struggle with that output.

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What you really want is that my application can talk to your application using an exposed and well documented

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API.

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Now that's the theory.

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In reality, APIs change.

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In reality, not all devices use the same API.

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So if you talk to DNA center, the APIs that it uses will be different to an iOS errata and it can change

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from version to version.

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That is a frustration of APIs, but long term, hopefully Cisco will standardize the APIs more and more.

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This is where the world is going.

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We are no longer going to manually configure devices using the CLI.

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You're going to have applications interacting with other applications and programming other applications.

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So my program will program that program in the same way that an Alexa can be used to interact with many

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devices out there.

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Okay.

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So let's get started with some practical demonstrations.