2.7 Compare and contrast Internet connection types, network types, and their features.
- Internet Connection Types
- Wireless Internet Service Provider (WISP)
- Network Types
- Local Area Network (LAN)
- Wide Area Network (WAN)
- Personal Area Network (PAN)
- Metropolitan Area Network (MAN)
- Storage Area Network (SAN)
- Wireless Local Area Network (WLAN)
Internet Connection Types
How does internet get into your building? There are several methods
|The satellite internet has four components
1 – A satellite high up orbiting the Earth
2 – A dish. You install the dish at your facility and point it at the satellite. The dish can only receive data from the satellite. The dish also has a transmitter, which can only send data. The dish and the transmitter must have a line of sight with the satellite.
3 – The dish and the transmitter are connected to a modem that is inside the building. The modem converts the satellite signal into an ethernet signal.
4 – A ground station. The ground station is connected to the rest of the internet via fiber optic cables and routers. The ground station sends and receives signals with the satellite.
For example, say you want to access a YouTube video
-Your computer makes a request for a YouTube video
-The request is sent to the modem
-The modem converts the request into a satellite signal and sends it to the transmitter
-The transmitter sends the request to the satellite orbiting the earth
-The request is downloaded by the ground station
-The ground station sends the request over the internet until it reaches YouTube’s servers
YouTube’s servers respond with the video
-The ground station receives the video and transmits it to the satellite
-The satellite transmits it to the dish mounted outside your building
-The modem receives the signal and converts it into an ethernet signal
-The ethernet signal is transferred to your computer and you can watch the video
Satellite internet was popular in rural areas where no cables existed. The problem with satellite internet is that it has a latency of up to 500 ms which is not good enough to support VoIP or video conferencing applications.
Satellite is making a comeback because of technology like Starlink. Starlink uses satellites that are much closer to the earth. Older satellites were placed in an orbit that was 35,000 km above the earth (35786 km to be exact). This is called the geostationary orbit and allows the satellite to stay in the same spot above the earth at all times.
Newer satellites like Starlink are placed 550 km above the earth. They have a latency of 45 ms because the signal takes much less time to travel between the earth and the satellite.
Since the earth is round, the higher up the satellite, the more area it can cover. Since Starlink is so low to the earth, each satellite can only cover a few hundred square km, and we need many satellites to make the system work. The Starlink satellites use lasers to communicate with each other. This allows them to create a mesh network.
|Cable internet is delivered over a coaxial cable. It requires a cable modem and may have high latency, although not as high as satellite. We can obtain speeds of up to 1 Gbps.
Most urban areas have cable. Many cable companies are upgrading their infrastructure from cable to fiber, which provides for faster speeds.
|Digital Subscriber Line is delivered over a phone line. You can use the phone and DSL internet at the same time. DSL requires a DSL modem and achieves speeds of up to 150 Mbps.
DSL can be delivered over any phone line provided that the ISP’s central office has the required equipment. DSL speeds may be as slow as 3 Mbps in areas where the telephone wiring is not as good or where the ISP does not have adequate capacity.
|Dial up internet is delivered over a phone line, but you can’t use the internet and the phone at the same time.
Speeds are very slow – a maximum of 56 Kbps. Dial up does not require much infrastructure and many places still have Dial Up connections as a back up.
|Fiber optic internet is delivered over a fiber optic cable. It requires a media converter to convert the fiber to copper (ethernet) and a modem/router. These may be combined in a device called an ONT (Optical Network Terminal)
Fiber provides speeds of 1 Gbps or more. Fiber is not available in all areas, but internet providers are installing fiber in more areas. Many phone and cable companies are upgrading their infrastructure to fiber.
Fiber provides the lowest latency of any internet connection.
|Cellular internet is delivered through a cellular modem (basically like the data on your cell phone). It can provide speeds of up to 100 Mbits/s.
It is available anywhere that has a cellular data connection. When the connection (signal strength) is poor, you can add a cellular antenna to boost the signal.
Cellular internet has high latency and can be expensive because you must usually pay per GB of bandwidth used.
As 5G becomes more widespread, cellular internet is becoming more affordable and reliable. Cellular service providers are selling packages with unlimited bandwidth in areas where 5G is installed.
Many organizations commonly use cellular internet as a backup for their primary internet connection. The router is programmed to fail over to the cellular backup when the primary internet connection fails.
Cradlepoint is a popular manufacturer of cellular modems and routers, but many other manufacturers produce routers that can connect to a cellular network.
|Line of Sight
|A line-of-sight network is also known as Point-to-Point. We discussed it in a previous section.
It works at a range of up to 25 KM. The system requires two antennas – one at the subscriber’s facility, and one at the ISP’s facility. The ISP’s facility is connected to the rest of the internet.
The ISP can have one central antenna surrounded by many subscribers.
Line of Sight internet is popular in areas where there is no cable. It requires that both antennas have a line of sight. The installation cost can be very high.
|A WISP or Wireless Internet Service Provider is an ISP that provides wireless internet.
A WISP will buy a fiber optic internet connection and install it in the center of the area that it wishes to cover. It will connect this fiber to an antenna and broadcast the signal in all directions.
The WISPs customers will install antennas on their buildings and point them at the WISPs central antenna. These antennas will provide connectivity to the internet.
WISPs are common in rural and urban areas.
There are several types of computer networks
|Local Area Network
This is the internal network for the home or office Devices on this network typically are assigned private IPs
|Wide Area Network
A WAN could refer to the internet.
Generally, a WAN is a special internet connection that allows multiple LANs to connect to each other, even if they are far apart.
Devices on a WAN act as if they are all on the same LAN.
To set up a WAN, you must negotiate with an ISP or multiple ISPs to carry the traffic between the different LANs, and to do so at a low latency. In other words, the ISP will prioritize your traffic so that you do not experience slowness.
A new technology is the SD-WAN, or Software Defined Wide Area Network. The SD-WAN uses a special router to build a WAN over a normal internet connection (or combination of connections). SD-WANs take advantage of cloud data centers that help them route traffic efficiently.
|Personal Area Network
Network between devices belonging to a single user or in a specific workspace. Your PAN might include your laptop, smart phone, and watch.
|Metropolitan Area Network
Larger than a LAN but smaller than a WAN
Can use Point-to-Point connections to connect them
Typically, LANs in a single city can form a MAN.
A MAN is usually connected by dark fiber. Dark fiber is fiber optic cable that an ISP installs and rents out. If you rent a dark fiber, you can transport any type and quantity of data over it.
|Storage Area Network
A SAN is a network that connects storage appliances to servers and other devices.
A storage appliance is a type of hardware that is dedicated to storing large amounts of data.
SANs communicate via ethernet, Fiber Channel, Fiber Channel over Ethernet. Fiber Channel uses special switches known as fabric interconnects.
|Wireless Local Area Network
A WLAN is a portion of the LAN that is wireless. When wireless access points are connected to the LAN, they connect wireless clients with the rest of the LAN.