There are many different ways to connect to the Internet. In this video, you’ll learn about cable modems, fiber connections, satellite networking, and much more.
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There are many different ways to connect your home and your business to the internet and in this video we’ll look at a number of these internet connection types. A very common internet connection type in the home is a cable modem. We sometimes refer to this as broadband communication because we are sending information over many different frequencies on the same wire. This also can be different traffic types on these different frequencies, so it’s not uncommon to have video, voice, and your data coming across this single cable modem connection.
You may sometimes hear this cable modem connection referred to as DOCSIS, which is data over cable service interface specification. This is the standard that is used on cable networks to send data across to these cable modems. This is what we consider high-speed networking. These cable networks can go very high speeds. Very commonly you’ll find four to 250 megabits per second, but you can get up to gigabit speeds running on these cable modem connections.
The cable company isn’t the only one providing internet connectivity. Very commonly your local telephone company is providing connectivity through DSL connections. This is technically ADSL, for asymmetric digital subscriber line. This uses your existing telephone lines, which makes it very easy to simply add a modem into your home and you’re connected to the internet. One of the challenges you have with DSL is that you have to be somewhat close to a central office or a CO.
The download speed that you’re going to have will be directly proportional to how far away you are from that central office and the limitation is somewhere around 10,000 feet, which is not an incredibly long distance when you consider how dispersed are different homes are away from these central offices. You’ll generally get 52 megabits per second down and 16 megabits per second upstream, but these numbers can vary widely depending on how far away you are from the CO. As you begin to move farther away from the CO, you’ll start to see these speeds get slower and slower.
Another type of internet connectivity we don’t see much any longer are dial-up connections. These are using our existing analog voice telephone lines and sending data communication over that connection. You’ll commonly see 56 kilobits per second modems. This is significantly slower than a DSL connection or a cable modem connection, although you can compress the data bit to get speeds up to 320 kilobits per second. Obviously, when you compare this relative to cable modem or DSL, these speeds are relatively slow, which makes using a dial-up connection difficult to scale, especially if you need to connect many different people to the internet.
Although you no longer tend to find a dial-up connection at home, it’s very common to use them in large enterprise environments. If you lose the connection to a remote site over a cable connection or a DSL, you might be using these traditional analog dial up modems to provide some connectivity back to those sites.
We’ve been using fiber in the enterprise for many years to provide internet connectivity, and we’re starting to see more fiber rolled out to the home. This provides very high-speed networking and allows us to send many different services over that single fiber. So voice connectivity, our video connections, and our data can all be running over a single fiber to our house.
This increase in available bandwidth also brings a number of new services. You have a lot more HD channel connectivity than you might have with a copper-connected service. And this also allows you to send and transfer a lot of different types of data out to the cloud. You might also see enhanced capabilities with DVR and video capabilities using this additional bandwidth.
Our internet connectivity doesn’t have to be limited to connectivity on earth. We can sometimes connect to the internet using satellites that are in space. This satellite networking allows us to communicate directly to a satellite, which then sends that data to a station down on earth and then reverses that to get the data back to us. This has, as you might expect, a relatively high cost compared to traditional terrestrial networking such as cable modem or DSL connectivity, but your speeds are pretty good. You get around 50 megabits per second down, three megabits per second upstream are common to find with satellite networking, but this does allow you to connect to sites that may not have the ability to connect to a cable modem or DSL connection and you’re able to be in a remote site or somewhere far away from the central office and still have relatively high-speed internet connectivity.
There are a number of challenges with satellite networking. One of these is that you have a relatively high latency. It does take time to get that data up to a satellite and then back down to earth. So if you have an application that requires a very low amount of latency, this may not be the type of connectivity you’d like. Those of you that have satellite connections for your television at home know that the other problem with this type of connectivity is when it rains. If you have a very heavy thunderstorm, that rain coming down can block this two gigahertz signal from going from your dish out to that satellite connection. So while this storm is going on outside, you won’t have any type of Internet connectivity.
An older style of internet connectivity, which still has some limited functionality in today’s markets, is ISDN. It stands for integrated services digital network. There are two different types of ISDN you might find. One is what we call an ISDN basic rate interface, or BRI. You’ll sometimes hear this referred to as a 2B+D. This was referring to the two bearer channels, which are actually sending data over these ISDN connections, and the single signaling channel, or D, channel.
These two bearer channels are 64 kilobits. So we’re not talking about high-speed connectivity that you might have with cable modem or DSL, but this is certainly better than using a dial-up connection. The signaling channel, or D channel, which is a 16 kilobit per second channel when you’re working with BRI is managing all of the communication over this connection. So it sets up the connection, it tears down the connection, and sends any management information while the call is going on.
A larger scale ISDN is the primary rate interface ISDN, or a PRI. This is usually delivered over a T1 or E1 connection depending on what country you’re in. And a T1 connection supports 23 bearer channels and a signaling channel. And E1 supports 30 bear channels, a signaling channel, and a separate alarm channel.
Although you could certainly use these very large bearer channels to send internet connectivity over a PRI, it’s also common to see PRI used as voice channels that are coming from your public switched telephone network, that’s your local telephone company, and connecting to a private branch exchange or a local phone system inside of your company. If you’re not converting over to voice over IP, you may be using some of these legacy ISDN connections to provide all of your voice communication.
Modern cellular networks allow us to have internet connectivity from practically anywhere. We now have a mobile phone that allows us to have both voice and data access simultaneously. These cellular networks have many different antennas set up in a geographical area where the land is separated into cells. That’s where the idea of a cellular network comes from. And our mobile devices use these antennas to be able to communicate back and forth to the internet.
Not only do our mobile phones have internet connectivity, but we can connect a wire from a laptop to our mobile phone and provide the laptop with the internet connectivity as well. That’s called tethering. And if you’re connecting many devices to your mobile phone over 802.11 wireless connectivity, you’re effectively turning your phone into a mobile hotspot. This way anyone in your local area is able to use your internet connectivity on your phone to provide internet access for all of your devices.
In your metropolitan area, you may have the option of a line-of-sight internet service. This is a wireless internet service that’s able to provide access over a very wide geographical area. This is a line-of-sight communication, so there’s usually antennas placed very high that are able to communicate to many different homes simultaneously in one geographical area. There are also options for non-line-of-sight, this would usually be slower speeds using lower frequencies. And a very common type of line-of-sight service is WiMAX. This is the worldwide interoperability for microwave access. This provides wireless high-speed internet connectivity by simply putting an antenna outside of your house and accessing those WiMAX antennas in your area.
Category: CompTIA A+ 220-1001