T. Meredith

5460 – Summer 2014

Network Components

• Hub/Switch

• Router

• Bridge

• Gateway

• Firewall

• Wireless Access Point (WAP)

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

http://upload.wikimedia.org/wikipedia/commons/thumb/d/d9/4_port_netgear_ethernet_hub.jpg/300px-4_port_netgear_ethernet_hub.jpg

• 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Today, hubs are usually superseded by…

Switch

http://img.directindustry.com/images_di/photo-g/rack-mount-managed-ethernet-switches-66478-5577201.jpg

• 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

Hub vs. Switch - clarifying differences…

https://www.youtube.com/watch?v=JtTkW6pFxls

http://content.answcdn.com/main/content/img/CDE/HUBSWIT.GIF

Bridge

http://www.foundvalue.com/upload/images/products/alindo_632837444737955000_linksys_wet11.jpg

• 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

http://www.igcseict.info/theory/4/hware/files/stacks_image_7406_1.png

Router

http://www.wikimedia.org/wikipedia/commons/3/34/Linksys-Wireless-G-Router.jpg

• 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

http://www.igcseict.info/theory/4/hware/files/stacks_image_7380_1.png

Gateway

http://www.logicsupply.com/daq-ml250/#

• 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

http://upload.wikimedia.org/wikipedia/commons/thumb/c/c5/Homenet.svg/310px-Homenet.svg.png

Firewall

http://eandt.theiet.org/magazine/2013/08/images/640_cisco-asa-firewall.jpg

http://www.igcseict.info/theory/4/hware/files/stacks_image_7419_1.png

The position of a firewall between a LAN and the Internet

• 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)

Wireless Access Point (WAP)

http://img.directindustry.com/images_di/photo-g/wireless-access-points-waps-61398-3133227.jpg

• 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)

http://www.pcguidebook.com/images/usingaprintserver.gif

A wireless access point added to a network

Network Diagram

Often integrated

(or Gateway)

• Black, U. D., & Habraken, J. W. (2009). Sam’s teach yourself networking in 24 hours. Indianapolis, Ind: Sams.

• All prices from: http://www.cdwg.com (accessed July 7, 2014)

• All images/media credited in individual slides

References