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Network Hardware

There are dedicated pieces of hardware that make a network function effectively and efficiently. These pieces of hardware are all advancements of the Ethernet network protocol. Most network hardware today is based on the twisted pair or fiber cable connection medium.

Hub

A hub serves as a central node or device in a computer network, connecting multiple Ethernet segments, computers, and devices together and treating them as a single segment. A hub provided the first method for which computers could share a single connection to the internet. Hubs work at a maximum speed of 100 million bits per second or 100Mbps.

It connects computers together through what is known as a shared medium. Only one computer can talk to the hub at a time, and that computer cannot both send and receive data at the same time.

A hub cannot distinguish who or what is connected to each of its ports. When it receives data from a given connection (see Fig. 1), that data is broadcast to each connected segment/device (see Fig. 2). This method of communication is what allows the hub to resemble a single segment. It is up to the device to either accept or reject the pieces of data. However, constant broadcast of information to all parties creates data collisions that interrupt and degrade service, and poses a security risk. For example, if one connected device receives a virus, they all receive a virus.

Figure 1: Packet of data sent to hub.

Figure 2: Packet of data broadcast to all connected nodes.

Switch

Switches are more advanced versions of hubs. Unlike the hubs, switches do not use a shared medium, keeping all of the connections separate. For example, if computers A, B, C, and D are connected to a switch, the switch will allow computers A and B to interact without sending unrequested data to C and D. Because the switch will not send data to unintended recipients, they are more secure than hubs. The maintenance of separate recipients and control of data between them is referred to as intelligence.

Figure 3: Packet sent to switch

Figure 4: Packet sent to addressed node

Router

A router is a specialized computer that controls how data moves between networks, not within networks. While switches deliver information that they are given to specific paths, routers can determine what path that data should follow based on a routing configuration table. This table keeps track of all connections to the router and all possible paths that exist between networks. This allows the router to choose the quickest/best path for data.

Different Kinds of Routers:

Internet Connection Sharing is when you have several computers connected together though a hub or a switch, but one of those computers is connected to the Internet in addition to the hub or switch. That computer can share its Internet connection with the other computers, and then acts as a router for the rest of the computers.
Home Broadband routers are used to connect multiple computers together in a home setting. They are individual devices and have specialized software just for routing data between the home network of computers and the Internet. These devices can have other features built into them, such as wireless connectivity hardware, software to perform NAT, or firewall software.
Office Network routers are used to connect more than two computers together in an office setting. They are usually individual devices and contain some rudimentary security protocols to protect the network from low-level security attacks.
Major Traffic routers are used in nexus points on the internet that must examine and transfer very large amounts of data.

Figure 5: Data packet being sent to NAT router.

Figure 6: NAT router translating/forwarding data packet.

Firewall

A firewall is a piece of hardware or software that works to prevent unauthorized communications from entering or exiting the network. The firewall will use a set of rules to determine whether or not a specific piece of communication is allowed to pass. The physical firewall may be a computer or other intelligent device that filters all traffic for the network. A firewall can also be a piece of software that is run on an individual computer, typically for personal use.