We define the structure of our networks based on the reach and functionality of the data flows. In this video, you’ll learn about WAN, MAN, LAN, WLAN, PAN, SCADA, and Medianet infrastructures.
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A wide area network means that we are going to be communicating over a relatively long distance. A local network would be something in our building. We can connect it with an ethernet connection. But if you need to go outside of your facility, you going to need to communicate over a wide area network. This is when you’re connecting up a LAN in one facility with the LAN in another facility, and you somehow have to be able to connect those together. You’re generally going to a third party to provide this wide area network connection, somebody who specializes in connecting these lands together. They might give you a point to point link, or an MPLS connection, or they might give you a satellite link. This is a non terrestrial link, where we’re going up to a satellite and then back down to communicate.
But in each one of these cases, we’re communicating over a very long distance with a wide area network. If it’s not a local area network, and it’s not a wide area network, it’s probably something in the middle, like a metropolitan area network. This is a network that’s in, generally, a very confined geographical area. So it’s in a metropolitan area in a city or county. It’s a little bit bigger than a LAN, but a little bit smaller than a WAN. You usually connect sites together using ethernet. This is a service called Metro ethernet, where the provider is simply giving you an ethernet connection on both sides, you connected together, and it doesn’t matter how the provider is getting it from one side to the other. They’re simply giving you an ethernet connection, and you’re connecting natively, without any additional wide area network technologies.
It’s very common to see government organizations taking advantage of a metropolitan area network, or even building one themselves, since they already have access to the streets and the right of way, they can simply run fiber in the same conduit that all of their other utilities are in, and they can easily connect up all of their sites over their own fiber, in their own copper.
Of course, in your building, you probably have a local area network. And of course, the term local is very relative, but this generally means anywhere that you’re connecting things together with your own ethernet switches. This may be a campus, it may be a single building, but it’s usually something that you have complete control over, and you’re not requiring a third party to help connect these different entities together. It’s very common to see ethernet and things like 802.11 wireless on a local area network. If you’re going over slower link than that it’s probably not something you have control over and therefore, is not a area network.
If you have a wireless network infrastructure, then you have something called a WLAN, for a wireless LAN, and generally we’re using 802.11 to be able to send out that wireless signal and have other devices communicate back. This is usually done within a building, or a limited geographical area, because you are limited as to how much power you can put out of one of these wide area network access points. If you need a longer distance, or you need to extend that wide area network, you simply add additional access points. It’s very common to see this in a large downtown area, or perhaps in a park, where you have many different access points to be able to have this wireless network communicate throughout the entire area.
A personal area network, or a PAN is a network that’s just around you. Generally, we think of a Bluetooth network as being this. Since Bluetooth has a limited amount of distance that it can travel, we usually see keyboards and mice in our ear pieces, all communicating over this personal area network Bluetooth connection. It’s very common to see this in an automobile, for instance. That’s certainly very personal, and you can have your mobile devices communicate to your radio over this wireless Bluetooth connection, or maybe integrating with your telephone, so that you can have hands-off while you’re driving.
You may also see a personal area networking used with a mobile phone, or some other type of music device, so that you can have a wireless headset. You can go on a jog, and you won’t have any wires. You’re simply using this personal area network to be able to send that signal back and forth between those devices. And we’re seeing an increasing number of devices connected with your health. You can wear different sensors on your phone, or on your body, and it will get telemetry from those sensors and be able to report back to your mobile device using this personal area network.
A very specialized kind of network is a SCADA network. SCADA stands for Supervisory Control and Data Acquisition System. You might also see this referred to as an ICS network or Industrial Control System. That’s because this network is controlling something like an industrial facility, like something that’s doing power regeneration, or refining. Maybe it is a floor of manufacturing equipment, and you have to have some way to control this equipment. You do it all by using these SCADA protocols. This is a very distributed system. You have these separate programmable logic controllers that are used on these industrial devices, and they are usually managed through these remote terminal units. There’s obviously a lot of security these days around these industrial systems, and so usually you’ll find a SCADA network is something that is not connected to something like an internet connection.
We’re using a lot of different kinds of media over our networks these days, and a Medianet is a Cisco term for these media applications running on a Cisco architecture. This may be doing streaming video, maybe performing TelePresence type technologies, it may be doing desktop collaboration. Cisco calls this all a Medianet. These are managed as a single, unique service. The network devices understand the media that’s being provided to them, and the applications themselves are now able to take advantage of voice and video, and data all at the same time. We commonly see these medianets being used for applications like video teleconferencing. We used to use ISDN connections, or even multiple ISDN connections, to be able to support a video conference. These days we do it all over IP, using some specialized protocols, like Session Initiation Protocol, and using all of these voice-over IP technologies to send the voice and the video over our existing IP networks.