Network Devices

What is an Injector?

A PoE injector is a device that can be used to provide PoE to a device when the switch does not support PoE. It plugs into the wall; then a line providing data and PoE is run to the device, and another cable runs to the switch,

What is Ethernet over Power?

Ethernet over Power is a technology designed to enable the sending of Ethernet frames over the power lines in a facility.

What is a Hub?

Hubs are used in networks that use twisted-pair cabling to connect devices, and they can be used to join segments into larger networks.

What are the two types of hubs and what do they do?

Hubs can be passive or active. If the hub does nothing except provide a pathway for the electrical signals to travel along, it is passive. It if regenerates the signal, it is considered active.

What is a Switch?

Like routers, switches are the connectivity points of an Ethernet network. Devices connect to switches via twisted-pair cabling, one cable for each device. The difference between hubs and switches is in how the devices deal with the data they receive. Whereas a hub forwards the data it receives to all the ports on the device, a switch forwards it to only the port that connects to the destination device. It does this by learning the Media Access Control (MAC) address of the devices attached to it and then matching the destination MAC address in the data it receives.

What is a Managed Switch?

Managed switches are those used in an enterprise network. These switches can be config-ured with advanced features such as virtual LANs (VLANs). They are managed remotely, using either a command-line interface or in some cases a GUI management interface.

What is Power over Ethernet (PoE)?

Many times when installing devices, the device needs to be located far from an avail-able power outlet. On switches that support Power over Ethernet (PoE), the switch can supply power on the same data cable used to connect to the device. So if you get the device within 100 meters of a switch, you can eliminate the need to install costly power outlets.

What is a Cloud-based Network Controller?

The new paradigm in networking is to move the intelligence from the routers, switches, and access points to a cloud-based network controller. Software-defined networking uses a controller to manage all the routing switching and wireless control while the devices simply handle data forwarding

What is a Firewall?

A firewall is a server that sits between the internal network and the rest of the world and filters what goes between the two.

What is a Network Interface Card (NIC)?

Network interface cards (NICs) are expansion cards that are installed into slots in a desktop computer. These cards connect the computer to a network. In most cases today, devices large and small have integrated or built-in network interfaces.

What is a Cable/DSL modem?

A modem, short for "modulator/demodulator," is a device that converts the digital signals generated by a computer into analog signals that can travel over conventional phone lines. The modem at the receiving end converts the signal back into a format that the computer can understand. Modems can be used to connect to an ISP or as a mechanism for dialing up a LAN. Cable and DSL modems, however, are not true modems in that they do not convert between analog and digital. These devices are really systems that take the information and place it on either the cable or DSL network so the ISP can transfer it to the Internet and back.

What is a Patch Panel?

A patch panel is a device to which the cables running through the walls from the hosts are connected. Then shorter cables called patch cables run from the patch panel to the switch or hub.

What is a Repeater?

A repeater or extender is a device that regenerates any signal that goes through it. It can be used to extend a cable run that exceeds the maximum allowable distance.

What is a Router?

A router is used to connect LANs; you can even use a router to connect dissimilar topologies that use the same protocol, because physical specifications don't apply. A router can be a dedicated hardware device or a computer system with more than one network interface and the appropriate routing software. All modern network operating systems include the functionality to act as a router.

What are Access Points (APs)

Access points (APs) are transmitter and receiver (transceiver) devices used to create a wireless LAN (WLAN). An AP is typically a separate network device with a built-in antenna, transmitter, and adapter. APs use the wireless infrastructure network mode to provide a connection point between WLANs and a wired Ethernet LAN. APs also typically have several ports, giving you a way to expand the network to support additional clients. Depending on the size of the network, one or more APs might be required. Additional APs are used to allow access to more wireless clients and to expand the range of the wireless net-work. Each AP is limited by a transmission range—the distance a client can be from an AP and still obtain a usable signal. The actual distance depends on the wireless standard being used and the obstructions and environmental conditions between the client and the AP.

What is a Bridge?

Bridges are used to divide larger networks into smaller sections. Bridges accomplish this by sitting between two physical network segments and managing the flow of data between the two. By looking at the MAC address of the devices connected to each segment, bridges can elect to forward the data (if they believe that the destination address is on another interface) or block it from crossing (if they can verify that it is on the interface from which it came).

What is an Unmanaged Switch?

Unmanaged switches are those that cannot be managed remotely; and while they can pro-vide basic switching services (full duplex service and the like), they cannot be configured with the more advanced services of a managed switch