1. Network Components
T. Meredith
5460 – Summer 2014

2. Basic Components of a Computer Network
Not all components are used in every network environment – however, this presentation discusses all of them since any or all may be present in networks you will support…
Hub/Switch
Router
Bridge
Gateway
Firewall
Wireless Access Point (WAP)

3. Hub Today, hubs are usually superseded by…
Transmits data from one port/device to all other devices connected to the hub
Operates on Layer 1 of OSI model
Rarely used today, replaced by switches
Price: NA/obsolete
Today, hubs are usually superseded by…

4. Switch
Transmits data from one port/device to another port/device connected to the switch, correctly identified by MAC addresses, ATM, or MPLS; only sends data to correct port/device, unlike hub
Operates on Layer 2 of OSI model
Price: $25 - $3000 (as pictured, $825)
Diagram of hub/switch placement in a network

5. Hub vs. Switch - clarifying differences…

6. Bridge
Does many of the same things as a switch, BUT does not use ATM or MPLS (MAC addressing only)
Typically connects two different parts of the same LAN
Price: $30 - $17,000 and up (as pictured, $100)
A bridge connecting two smaller groups of clients on a single LAN

7. Router
Transmits data packets between networks by using routing table to determine proper destination
May include switch, firewall, or other network functions all in one device
Price: $30 - $600 (as pictured, $62)
A simple network showing a router connecting a LAN to the Internet

8. Gateway
Similar functions as a router, but more complex since it can be used to connect two different networks (e.g., LAN and WAN/Internet) using different protocols (e.g., VoIP)
Can operate at any OSI layer
Cost: $40 - $17,000 and up (as pictured, $630)
An example of a residential gateway on a simple home network

9. Firewall
Protects a network by blocking unrecognized/unauthorized traffic from outside the LAN
Can be a physical device OR software running on a router or other computer
Price: $5/year minimum (software license), up to $2,000 Cisco rack-mountable devices (as pictured, $640)
The position of a firewall between a LAN and the Internet

10. Wireless Access Point (WAP)
Broadcasts a WiFi signal to allow wireless devices to connect to a wired network
Usually connected (wired) to a router, but some WAPs and routers are single integrated units
Price: $25 - $3,000 (as pictured, $1100)
A wireless access point added to a network

11. Network Diagram
Often integrated
(or Gateway)

12. References
Black, U. D., & Habraken, J. W. (2009). Sam’s teach yourself networking in 24 hours. Indianapolis, Ind: Sams.
All prices from: (accessed July 7, 2014)
All images/media credited in individual slides