Lesson 2

A device necessary for sending and receiving data over analog lines, such as phone or cable lines.

Modem

A device that acts as a point of connection between two or more networks that forwards data packets between networks. To have internet in your home, you need an this device that connects the networks on the internet to the network of your home. You can access the internet’s network either through a wired Ethernet port of via Wi-Fi.

Router

This device is used to connect devices in a specific network and allows them to communicate efficiently within the network. It is a more complex version of a hub, in that they have the capability to add security measures and function far more intelligently, sending traffic directly from the sender to the receiver without the other devices being aware of the communication. Thus, this device is less chatty and allows for more simultaneous conversations between devices. Most internet routers include a this in the form of wired or wireless Ethernet connections.

Switch

This device is similar to a router in that it connects two or more networks. The difference is that the router analyzes data packets to determine where to send the packet next, whereas this device simply forwards the data to the next network without analysis. This make for fast data transfer that lacks versatility. These devices are not widely used in modern networks, as routers and switches are the favored devices.

Bridge

This is a device used to strengthen, replicate, and regenerate signals that are weakened (for example, because of distance) during transmission. In many large homes, the Wi-Fi signal does not extend to the end of the house farthest from the router. A range extender is a form of this device that takes the distorted Wi-Fi signal and transmits is to the formerly dead zone.

Repeater

This device connects the router to the network, takes the data packets from the router, and sends them to all of the devices connected on the network.

Hub

Operates at the Network and Data Link layers.

Switch (OSI)

Operates at the Network layer.

Router (OSI)

Operates at the Data Link and Physical layers.

Modem (OSI)

Operates at the Data Link layer.

Bridge (OSI)

Operates at the Physical layer.

Repeater (OSI)

This device is a data link layer device. It is available either as a standalone or integrated with other devices, such as wireless routers or modems that can plug in physical devices. It keeps the traffic between the source and destination ports from interfering with other devices in the network.

Switch

This device operates at the network layer and can connect your home network to the Internet. Or, in a business or institutional scenario, it can connect your webserver to your database server.

Router

This can operate at multiple layers of the OSI model, including data link, network, transport, session, and application - and in certain circumstances, presentation as well.

Firewall

At what layers does the firewall defines what traffic should go between two networks?

data link and network

At what layer are the firewall filter settings are port-based?

transport

The firewall that operates at the network and transport layers is called what?

the Layer 4 firewall

The firewall that works at the session, presentation, and application layers is what?

the Layer 7 firewall

What layer firewall is also smart enough to decrypt and analyze the content flowing through, thereby adding one more level of filtering to the IP address and port combination?

The Layer 7 firewall

What is a powerful tool that can help prevent malicious attacks like Structured Query Language, also known as SQL injection, or other malware?

A firewall

These types of are created when pairs of wires are twisted around each other to protect and cancel out interference from each other and outside sources. They are widely used as analog phone cables and in copper Ethernet cables.

UTP Cables

These types of cables are analog cables made of copper but specifically engineered with a metal shield intended to block signal interference. They are mostly used by cable TV companies to connect their customers to the company’s facilities.

Coaxial Cables

These types of cables use glass or plastic threads within cables to transfer data using light (lasers or LEDs) as opposed to traditional metal cables using electricity. They are useful for high bandwidth needs and transfer data digitally, making them more reliable and less susceptible to interference.

Fiber Cables

These types of cables are made up of one single glass or plastic fiber and can carry higher bandwidth for longer distances compared to multimode cables. They are typically used for longer distances and higher bandwidth applications.

Single-mode Fiber Cables

These types of cables are wider in diameter and allow for the transmission of light modes across the cable. They are effective over medium distances and are generally used within a LAN. They are less expensive than single-mode fiber.

Multimode Fiber Cables

These types of cables are used to connect two computing devices of the same type directly to each other. The transmit connector on one end of the wire is connected to the receive connector on the other. These cables are used less frequently today due to built-in capabilities in many standards.

Crossover Cables

These types of cables are used to connect a device to a wall outlet or networking panel. They are commonly used to wire servers in a rack to a switch or connect devices to a network. They are similar in appearance to crossover and UTP cables.

Patch Cables

The ________________, an association of professional electronic and electrical engineers responsible for creating networking standards.

IEEE (Institute of Electrical and Electronics Engineers)

The IEEE standard for wired Ethernet networks.

802\.3

The IEEE standard for wireless networks.

802\.11

A wired Ethernet standard that provides 1 Gbps transmission over UTP cables.

1000BASE-T

The ability to power a low-power device without plugging it into an electrical outlet, reducing cabling.

Power over Ethernet (PoE)

A wireless networking standard that adds multiple-input multiple-output (MIMO) technology, increasing range and bandwidth.

802\.11n

A wireless networking standard that delivers high data rates, up to 1.3 Gbps, in a three-signal design.

802\.11ac

A wireless networking standard operating in frequency bands below 1 GHz, designed for IoT devices with limited bandwidth needs over larger distances.

802\.11ah

The rebranded name for the 802.11ax standard, which adds support for the 6 GHz frequency range and provides speeds of approximately 1-10 Gbps.

Wi-Fi 6

Supports up to 10 Mbps (Megabits per second) for up to 100 meters and is commonly used for phone lines today.

Cat3

Supports 16 Mbps for up to 100 meters and is not commonly used today.

Cat4

Used in Ethernet LANs containing two twisted pairs allowing for up to 100 Mbps up to 100 meters between the device and the switch, hub, or router. This has been practically replaced by the Cat5e specification.

Cat5

Doubles the number of twisted pairs to four for up to 1 Gbps (Gigabits per second) over up to 100 meters.

Cat5e

Also used in Ethernet LANs and data centers. It is made up of four tightly woven twisted pairs (more twists per linear foot) and supports 1 Gbps for up to 100 meters or 10 Gbps for up to 55 meters.

Cat6

An improvement of the Cat6 standard, supporting the same standards and lengths (with the ability to run 10 Gbps over 100 meters maximum), but using a higher quality cable that is more resistant to interference. This is most commonly used in wired networks today.

Cat6a