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Network Hardware

Transmission Media

A transmission medium (the singular form of the word “media”) is a component that carries data from one network device to another.

  • Two types
    • Wired
    • Wireless
  • Both wired and wireless networks require network media to transfer data

Wired

Common Network Media

  • Twisted pair cables
  • coaxial cable
  • optical fiber cables

Twisted Pair Cables

Most widely used type of transmission media.

  • 100 meters (328 ft.) maximum segment length

Two types

  • UTP (Unshielded twisted pair)
  • STP (Shielded twisted pair)
    • consists of two separately insulated copper wires wound around each other
    • More expensive than UTP cables
    • The insulating protects from neighboring unshielded cables and electromagnetic interference from fluorescent lights

Coaxial Cables

Coaxial cables (often referred to as “coax”) have an outer plastic that is used in computer networks and to deliver cable TV services.

  • used for both baseband and broadband data communication services
    • Baseband is a signal at a very narrow frequency range on which data or information is superimposed and then transmitted
      • E.g., Ethernet LANs and serial cables
    • Broadband is considered high-capacity transmission technologies that are used to transmit data, voice, and video across long distances and at high speeds
      • E.g., coaxial, fiber optic, radio waves
  • 80x bandwidth of twisted pair cables
  • used by cable modems and televisions

Fiber Optic

Fiber-optic cable uses the concept of reflection of light through a core made up of glass or plastic. The core is surrounded by a less dense glass or plastic covering called the cladding.

  • 26,000x bandwidth of twisted pair cables

Wireless

Electromagnetic waves of different frequencies, such as infrared or radio waves, can be used to transmit data within a network with the use of Wi-Fi, Bluetooth, or even near field communication.

Tip

Radio wave are used to carry radio signals far distances to other networked devices

Common Network Media

  • radio waves
  • microwaves
  • infrared waves

Wireless technologies

  • Bluetooth
    • less than 30 ft
  • Wi-Fi
    • Less than 300 ft
  • Near-field communication (NFC)

Network Bandwidth

Network bandwidth is typically measured in megabits per second (Mbps) and gigabits (Gbps) per second.

CategoryMaximum Bandwidth
CAT11 Mbps
CAT24 Mbps
CAT310 Mbps
CAT416 Mbps
CAT5100 Mbps
CAT5e1 Gbps
CAT610 Gbps
CAT710 Gbps

Combining Networks

Local Area Networks (LAN) can be connected to create a larger network and sometimes become Wide Area Networks (WAN).

Devices used to connect networks:

  • Repeaters extend the range of cabling types so connections can be made by increasing the strength of the network signal.
  • Bridges are used to connect to different types of network and provide management of the message.
    • The bridge analyzes the network message and will only bridge the network if a message is addressed to a device on the other side.
  • Switches are used on LANs to reduce network traffic by management of network messages.
    • Older devices would broadcast a message to all devices on the LAN, a switch will only send to the destination device
  • Routers are the device that makes the internet possible.
    • acts as gateway to the internet
    • manage network traffic by having a routing table of known devices
    • If a destination address is unknown to the Router, it will forward the message to another router
    • This analyze and forward process continues until the message reaches the correct address

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