CompSci 5 Networks

Internet

collection of inter-connected networks

WAN

Wide Area Network collection of computer and networks spread over wide geographical area

IP address

Internet Protocol address unique to a network

What do packets contain

IP address its going to/come from, sewuence number of packet, number of packets in total, error checking data

Router

route data packets across a WAN, act as a node, if the packet is destinated in a LAN it will be routed to a switch

Switch

component of LAN that knowz MAC address of devices connected to it, it sends packest only to the intended recipient

NIC

Network Interface Card, operates wirelessly or wired with Ethernet cable, all devices connecting ot network have a NIC

MAC address

Media Access Control is assigned to a NIC, individual to a device, a device can have more than one (wired and wireless), 48 bit unchanging unique address

Wi-Fi

Wireless connections, family of protocols (rules) that make wireless networking smooth

Advantages of Wireless Networking

move around freely with their device, share files without being connected to a port, saves expense and time of sorting out cables, easier to add new devices, instant transfer of data is quicker

Disadvantages of Wireless Networking

FIle transfer speeds generally slower, connections can be obstructed by physical objects, generally less secure and easier to hack into

Risks of Wireless Networks

criminal activity - unauthorised users can use wireless connection to get into network and cause damage, bandwidth stealing - using internet connection to download software and slow network down, confidentiality - if network information isn’t encrypted intruder can gain access to confidential information

communications protocol

set of rules about how messages are formatted and transmitted

What are layers used for

each layer is responisble for a small function of the internet communications process

Advantages of seperating communications over different layers

each layer self-contained so can be changed without affecting other layers, discrete layers help interoperability between hardware manufacturers and computer systems, developers can concentrte on one network area without knock on effects

TCP/UDP operates on which layer

Transport layer

LAN

Local Area Network is a group of connected devices on a single site (relatively small geographical area), network usually managed by a single organisation

Benefits of Networking Computers

sharing resources, communication, centralised management - user profiles and security, software distributed rather than individually installed, backing up files centrally

Disadvantages of Networks

file srver goes down means no one can access files or do work, network faults could lead to loss of data, as network traffic increases so performance will be slow, hard to make system secure, viruses could infiltrate and infect all computers, larger network becomes it’s more dificult to manage

Topologies

The ways in which devices in a network are connected