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In this video, we're going to discuss JSON or JavaScript object notation.

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Why is this important?

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It's important because in the CNA blueprint there's a section under automation and programmability.

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6.7 Interpret JSON encoded data.

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This is something that you need to know for the exam.

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So make sure that you watch this video and that you understand, Jason.

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Okay.

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So let's start with why you've probably seen one of these before.

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Are you a human or a robot?

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Now the reason we have CAPTCHAs is because machines struggle with unformed data.

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If the data isn't clear, machines will struggle to interpret the data.

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JSON is a way to format data.

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It's also a way to send data from one machine to another.

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We as humans can interpret data quite easily, especially if it's slightly off.

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So as an example, if you type show version on a Cisco iOS device, so let's say classic iOS, the output

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will be different to a Cisco iOS X device, which is different to a Cisco Nexus device.

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The output will vary slightly.

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Now, that's not a problem for us as humans.

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We can make adjustments for the slight changes in the output of the data, but machines struggle with

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that.

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So we want data that is consistently formatted properly so that machines can communicate properly.

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As an example, if I switch to a switch using Python, so I connect to the switch using Python and type

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show IP route or show version.

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If I'm not using a JSON format, so the output is not formatted in JSON format or another format such

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as XML or YAML, it's difficult to write code that can interpret the data properly.

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Now, if Cisco once again have made things easier using pirates, so if you use pirates rather than

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say net mico to connect directly to a device using a Python script, the output comes back in a format

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that's easy to interpret using a Python script.

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But if you're using pure net mico or pure telnet and you simply typing show version and you're trying

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to pass that output, it's very difficult to write good python code to pass the output, number one,

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and secondly, to handle a situation when the output changes.

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So you upgrade the router as an example and the output formatting is different.

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Your python code will struggle to interpret that.

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So for machine to machine communication, it makes sense to use standard output and it makes sense to

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have a format that's easy to interpret, especially for machines.

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So to help us with JSON formatting.

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Let's start with a Tesla.

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Okay.

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I'm going to ask you some questions about this Tesla.

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Well, first question is, who's the manufacturer?

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That would be Tesla.

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What type of model is this?

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Model X.

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Notice how I've formatted this data manufacturer, Colon Tesla.

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This is known as a key and this is known as a value.

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So we've got a key value pair.

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What is the model?

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It's model X color, white fuel, electric miles per gallon.

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City 99 miles per gallon.

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Highway 93.

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Now I've simply pulled this information off Google.

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Hopefully it's correct, but don't get hung up about the data.

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Look at the format of the data.

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Again, we have what's called a key separated by colon, and then we have a value.

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You need to understand JSON formatting.

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That's an example of JSON formatting.

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It actually looks like this.

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We have to use double inverted commas.

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So it would be something like first name Colon, then David as an example.

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So JSON data is written as name of value pairs.

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So going back here, I said key.

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It could be also referred to as a name.

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So name value pair.

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Another example is last name and a value name.

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Value pair consists of a field in double quotes followed by a colon followed by a value.

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Make sure you understand that format.

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Now for the exam they are two JSON data types that you need to know objects and arrays.

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Let's start with an object.

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So adjacent object would look something like this.

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Notice we've got curly braces.

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Data is surrounded by curly braces and it's an unordered collection of key value pairs.

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So here's our key first name, David.

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A lost name, bumble notice, separated by a comma.

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Make sure that you know the format so curly braces surrounds the data.

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We've got key value.

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The keys and values use double quotes, not single quotes.

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Each key value pair is separated by a comma, except the last one.

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Trailing commas must not be used.

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Now it's going to be easier to look at it in this format, easier to read spaces or not important with

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JSON.

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So notice the curly braces.

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First key first value.

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Second key, second value separated by comma, comma.

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Third key.

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Third value.

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No comma.

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So if you put a comma here, that would be a problem.

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Make sure once again that you recognize this format for the exam.

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So just to summarize, a JSON object is an unordered collection of key value pairs.

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In other words, this is not ordered.

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It could be in any order.

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Doesn't matter.

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Surrounded by curly braces once again, key and value pairs are separated by a colon.

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Spacers don't matter, but make sure that the last one doesn't have a comma.

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Use double quotes, not single quotes.

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Booleans must be in lowercase.

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Boolean is basically is it true or is it false?

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So when you write true, it must be lowercase or false.

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It must be lowercase in Python, which I'll show you later in the course.

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It has to be true with uppercase.

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Now don't worry about learning python code for the exam once again.

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Now it's all very good and well, me showing you the stuff with PowerPoint.

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But let me show you this practically.

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You'll be able to download this PowerPoint presentation so that you have access to the details.

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So just click on the attachments to this course to get hold of this PowerPoint presentation.

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But I want to show you this practically, because it's going to be a lot easier to demonstrate this

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on a live Cisco device rather than just showing you the stuff with PowerPoint.

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Now, the great thing is that definite have a nexus always on sandbox.

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You can simply switch to the sandbox and you'll be able to try commands, which I'm going to show you

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right now.

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Now, on a mac, I'm going to use this command, but on windows you could use putty as an example to

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connect.

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Okay.

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So I'm going to copy this.

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Open up a terminal.

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I'll make this big to make sure that it's clear.

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And I'm going to paste that command in.

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So basically, I'm switching to Port 81, 81 using this username, and this is the DNS name of the router.

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I have to put my password in which is admin underscore one, two, three, four, exclamation mark or

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bang if you prefer.

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So there's the password.

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There's the username.

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This is the port.

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This is the protocol we need to use.

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And this is the domain name.

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Okay.

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It's complaining about my password.

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Let's try that again.

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Okay.

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So I've successfully logged in to this Nexus box.

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Hosted by Cisco Dev Net.

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Cisco Dev.

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Ned have made things so much easier because you can practice this stuff, you can try things using their

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free labs.

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Now on a Windows computer, you could use putty and switch to Port 81, 81.

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So S-H.

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Hostname is specs index OS management.

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Dot Cisco dot com and I can click open.

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You have to accept the public key.

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So I'm going to say yes.

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Login as admin admin underscore.

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One, two, three, four, exclamation mark or bang.

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And there you go.

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I've logged in.

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So show version.

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This command shows me that this is a nexus device.

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We can see.

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Various information about the device.

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We can see it's a 9000 V chassis as an example.

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So I'm going to jump back to my Mac and do this on my Mac show version on the Mac will show the same

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kind of information.