1.3.2 Networks - Hardware cont

1.3.2 Networks - Hardware cont

1. Networks can consist of many different hardware devices:

   • NIC - Network Interface Controller
     • Connects device to a network
     • Circuits that, in the past, were plugged into bus to produce signals that are placed on transmission medium, also to receive signals from it.
     • Designed to work with particular network standards, i.e ethernet - so common that most computers are built with ethernet circuitry built into motherboards
     • Advantages
       • Cheap
       • Easy to troubleshoot
     • Disadvantages
       • Need proper configuration
       • Require hard wired connection
   • Hub
     • Most basic networking device that connects multiple computers or other network devices together
     • No routing tables or intelligence on where to send information and broadcasts all network data across each connection
     • Cheap
     • Broadcasts to all ports
     • Half duplex
     • Shared bandwidth over ports
   • Switch
     • Connects devices together on a computer network, by using packet switching to receive, process and forward data to the destination device
     • Reduces number of broadcast domains
     • Supports VLAN's which can help in Logical segmentation of physical ports. Splitting up the broadcast domain
     • Intellegent device[compared to Hub's] which can make use of CAM table for Port to MAC mapping
     • Compared to Bridges ,Switches are more H/w oriented therefore operations are less CPU intense
     • Not as good as a router in limiting Broadcasts
     • Handling Multicast packets needs quite a bit of configuration & proper designing
   • Router
     • Connects networks by receiving data packets from one and forwarding them to another based on address info on packet
     • Determine where to send packet according to either a table of info about neighbouring networks or by using algorithm to determine optimum nest step
     • Easily Shared Internet
     • Complicated Setup
     • Data Overhead
   • WIC (Wireless)
   • Bridge
     • Provides interconnection with other bridge networks that use the same protocol
       • Can reduce network traffic on a segment by subdividing network communications
       • increase the available bandwidth to individual nodes because fewer nodes share a collision domain
     • Work at the data link layer of the Open System Interconnect (OSI) model, connecting two different networks together and providing communication between them
     • Cheap
     • Can extend network by acting as repeater
   • Repeater
     • Used to regenerate or replicate signals that are weakened or distorted by transmission over long distances and through areas with high levels of electromagnetic interference
       • improves wireless signal strength
       • Reduces impact of obstructions
       • Not cheap
       • May not boost signal strength as much as you want
   • Firewall
     • Protects network from unauthorised access
     • Stops unwanted packets from harming your computer
     • Can degrade performance
   • Proxy
     • Protect privacy
     • Proxy server acts as intermediary for requests from clients seeking resources from other servers
     • Protects from hacking
     • Bypassing blocked websites
     • Enhance the security and privacy
     • Any secured data can easily be seen by the proxy service provider
   • Internal DNS
     • Hierarchical decentralized naming system