Network Components Overview of Network Components

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A network can be as simple as a single cable connecting two computers or as complex as a collection of networks that span the globe.

Network infrastructure contains three broad categories of network components:

  • Devices

  • Media

  • Services

LANs, WANs, and the Internet Network Components

End Devices

An end device is where a message originates from or where it is received.

Data originates with an end device, flows through the network, and arrives at an end device

Network Components Intermediary Network Devices

An intermediary device interconnects end devices in a network. Examples include: switches, wireless access points, routers, and firewalls.

The management of data as it flows through a network is also the role of an intermediary device including:

Regenerate and re-transmit data signals.

Maintain information about what pathways exist through the network and internet work.

Notify other devices of errors and communication failures.

Network Components Network Media

Communication across a network is carried through a medium which allows a message to travel from source to destination.

Networks typically use three types of media:

  • Metallic wires within cables, such as copper
  • Glass, such as fiber optic cables
  • Wireless transmission

Network Components Network Representations

Network diagrams, often called topology diagrams, use symbols to represent devices within the network.

In addition to the device representations on the right, it is important to remember and understand the following terms:

  • Network Interface Card (NIC)

  • Physical Port

  • Interface

Network Components Topology Diagrams

Note the key differences between the two topology diagrams (physical location of devices vs. ports and network addressing schemes).

Two most common types of networks:

Local Area Network (LAN) – spans a small geographic area owned or operated by an individual or IT department.

Wide Area Network (WAN) – spans a large geographic area typically involving a telecommunications service provider.

Other types of networks:

  • Metropolitan Area Network (MAN)

  • Wireless LAN (WLAN)

  • Storage Area Network (SAN)


LANs and WANsLocal Area Networks

Three characteristics of LANs:

  • Spans a small geographic area such as a home, school, office building, or campus.

  • Usually administered by a single organization or individual.

  • Provides high speed bandwidth to end and intermediary devices within the network.

Three characteristics of WANs:

  • WANs interconnect LANs over wide geographical areas such as between cities, states, or countries.

  • Usually administered by multiple service providers.

  • WANs typically provide slower speed links between LANs.

The Internet, Intranets, and ExtranetsThe Internet

The Internet is a worldwide collection of interconnected LANs and WANs.

LANs are connected to each other using WANs.

WANs are then connected to each other using copper wires, fiber optic cables, and wireless transmissions.

The Internet is not owned by any individual or group, however, the following groups were developed to help maintain structure:

  • IETF


  • IAB

The Internet, Intranets, and Extraneous Intranets and Extranets

Unlike the Internet, an intranet is a private collection of LANs and WANs internal to an organization that is meant to be accessible only to the organizations members or others with authorization.

An organization might use an extranet to provide secure access to their network for individuals who work for a different organization that need access to their data on their network.

Internet Connections Internet Access Technologies

There are many ways to connect users and organizations to the Internet:

Popular services for home users and small offices include broadband cable, broadband digital subscriber line (DSL), wireless WANs, and mobile services.

Organizations need faster connections to support IP phones, video conferencing and data center storage.

Business-class interconnections are usually provided by service providers (SP) and may include: business DSL, leased lines, and Metro Ethernet.

Internet Connections Home and Small Office Internet Connections

Cable – high bandwidth, always on, Internet connection offered by cable television service providers.

DSL – high bandwidth, always on, Internet connection that runs over a telephone line.

Cellular – uses a cell phone network to connect to the Internet; only available where you can get a cellular signal.

Satellite – major benefit to rural areas without Internet Service Providers.

Dial-up telephone – an inexpensive, low bandwidth option using a modem.

Internet Connections Businesses Internet Connection.

Corporate business connections may require higher bandwidth, dedicated connections, or managed services. Typical connection options for businesses:

Dedicated Leased Line – reserved circuits within the service provider’s network that connect distant offices with private voice and/or data networking.

Ethernet WAN – extends LAN access technology into the WAN.

DSL – Business DSL is available in various formats including Symmetric Digital Subscriber Lines (SDSL).

Satellite – can provide a connection when a wired solution is not available.

Internet Connections Packet Tracer – Help and Navigation Tips

Overview of the Packet Tracer Program

Packet Tracer is a fun software program which will help you with your CCNA studies by allowing you to experiment with network behavior, build networks, and find the answers to your “what if” questions.

Internet Connections Packet Tracer – Network Representation.

This activity will allow you to explore how Packet Tracer serves as a modeling tool for network representations.

The network model in this activity incorporates many of the technologies you will need to master in your CCNA studies.


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