Topic 2: Connectivity

Home network: share an Internet connection.

Need to set up a local area network (LAN), Switch/hub/bridge, Wireless base station/adapter

Benefits:

Sharing Internet connection, fils, peripherals

Network interface card (NIC): connect computers to network (unless using Wi-Fi dongles)

Router: connect Internet from home network. Connects all computers to modem (e.g. ADSL, cable and wireless broadband (3G)) by giving them an internal IP address.

Powerline: network uses existing power wiring as a framework to carry data (e.g. HomePlug Power Alliance ).

Wired/ Cable connection: e.g. USB, USB 2.0, USB 3.0, USB Type-C, Firewire, Thunderbolt, Lightning, eSATA

• Cables must run from router to all rooms in house.
• Expensive installation.
• Very fast bandwidth
• Good security: physically plug computer into network
• Should not experience interference
• Cannot connect without a socket.

Wireless connection to router

• Only need wireless router 
• Cheaper installation
• Slower bandwidth
• Poor security: anyone can use it if no security password / key
• Affected by walls, electronic equipment
• Access from anywhere

Wireless networks: less secure than cable ones. No security = anyone within range can access it.

Security protocols: Wired Equivalent Privacy (WEP), WiFi Protected Access (WPA), WPA2

Ways if securing wireless networks:

Changing default admin password on router

Setting up encryption: scrambles data - only computers withright key can read it.

Setting up Media Access Control (MAC) address filtering - Each device has a MAC address- specify which addresses can connect to wireless network

Hding router - stopping router broadcasting its Service Set identifier (SSID)

Turning off router - not in use

Reducing transmitter power

Network connection: transferring bits (1s and 0s) between two devices.

Bandwidth: measurement of capacity, number of bts that go through network connection in 1 second. bits per seond (bps)

Latency: measurement of delay, time in millisconds between a bit keaving one device & arriving at other. milliseconds (ms)

User experience:

Streaming: high bandwidth network connection.

Quick search results: low latency network connection

Best networks (user's point of view): high bandwidth + low latency.

Convergence: performing functions originally performed by different device

Wi- Fi: needs to be withing range of wireless access point / hotspot

• Good range
• Up to 54 Mbps
• Widely available
• Fake hotspots can be made
• Cannot use if not in range.

Mobile broadband: can be made into a hotspot

Far h=greater coverage than WiFi

More secure - encrypted data

Have to pay + abroad roaming charges.

Downlaods limited

Lower bandwidth

Communicate wirelessly directly without need for transmitter between digital devices.

Wi-Fi Direct:

Wi-Fi Alliance- introduced Wi-Fi Direct- allows devices connect directly using Wi-Fi without need for wireless access point

Set up peer-to-peer networks

Allows devices use an access point for normal Wi-Fi use

Bluetooth

• Communicate automatically when within range - no user involvement
• Connect up to eight device at same time.
• Low power - no interfernce with other devices.
• Lower bandwidth
• Lower range

Protocols: rules that devices must follow when communicating with each other.

VoIP: Voice over Internet Protocol: transmitting sudio messages over Internet, make free calss, with webcam - video calls.

SMTP: Simple Mail Transfer Protocol: used email sent from sender's email client to sender's email server + email delivered to recipient's email server.

POP3: Post Office Protocol: mail server downloads email to computer, deleted from server - can be read offline

IMAP: Internet Message Access Protocol: email read on mail server - not deleted from server - can be accessed anywhere using any computer with an Internet connection.

HTTP: Hypertext Transfer Protocol: protocol of World Wide Web (WWW): Client requests files + web server responds by sending requested files.

HTTPS: Hypertext Transfer Protocol over SSL (Secure Sockets Layer): data transferred is encrypted - url should show as: https://

Digital certficates: padlock / security icon - issued by companies such as Norton - certify identity of website - can be faked

Preventing remote access: Firewall - software - permits / blocks connections between computer & other computers on network according to rules set. Not enough on its own - some malware (e.g. virus) works by shutting down firewall

Virus: program designed to cause other computer programs to malfunction or stop working. Can replicate themselves + can be passed on to other users in files & emails.

Additional precautions against viruses:

• Install updated antivirus software
• Run regular scans of files on computers
• Only download from trusted websites
• Only open emails & attachments from recognised senders
• Scan CDs, DVDs & memory sticks before accessing them
• Not use of pirate copies of CDs and DVDs
• Avoid file-sharing websites

Authentication: process of identifying individual - can prevent illegal access

Proof of identity: require username + password

Theft of equipment:

Chains & locks - fix desktop computer & laptop to desk.

Locks on doors

Blinds on windows

Radio Frequency Identification (RFID) chips: used in labels attached to items - scanner ead chip + identify product - sound alarm if item taken out of building

Biometrics e.g. fingerpting or iris - identify people based on physical characteristics

Fit blinds - people can't see in

Fit doors with security keypads + keep them locked

Issue swipe cards - store person's details in card stripes

Install burgler alarm - fit monitors in every room

Require people entering building to authenticate identity

Install closed circuit  television (CCTV) cameras inside & outside

Wired connections:

• USB, USB 2.0, USB 3.0, USB Type-C
• Firewire - high speed data ports.
• Thunderbolt - high speed data ports.
• Lightning
• eSATA - need external power source

Wired multimedia connections:

Digital audio (e.g. SPDIF) - type of digital audio cable used to connect devices in a home entertainment systems.

HDMI (High Definition Multimedia Interface) - transfers uncompressed digital data - used for connecting high definition video and audio devices.

Switches -  allow multiple inputs to be output to one (or more) device(s)

Splitters - allow one input to be output to multiple devices

Wireless connections:

• Infrared - transmits data over the infrared radiation spectrum
• Bluetooth - transmits data over short distances using ultra high frequency (UHF) radio waves.
• WiFi (Wireless Ethernet), WiFi Direct WiFi Direct - way of allowing two devices to easily communicate/ transfer data. - transmits data over short distance using UHF & SHF radio waves. All reasonably short distance to transfer data.

Security protocols: Each security protocol provides for the encryption of data over wireless networks.

• Wired Equivalent Privacy (WEP)
• WiFi Protected Access (WPA)
• WPA2

Telecommunications:

• Mobile phone networks (GSM, EDGE, 3G, HSPA, 4G) - Newer technologies (such as HSPA and 4G) greatly improve the speed at which mobile phone networks provide online access.
• Mobile phone bands (Dual, Tri, Quad) - dual, tri, quad and penta bands describe number of radio frequencies that a phone can use. The bands used dicatates whether your phone can access signal abroad, whch countries and how good that is.
• Landline phone network
• Fibre optic cable network

Equipment needed to create a home network:

• Modem - Types of modem include ADSL, cable and wireless broadband (3G)
• Router
• Switch/hub/bridge
• Wireless base station/adapter
• Powerline networks - uses existing power wiring as a framework to carry data (e.g. HomePlug Power Alliance )

Radio (AM/FM/digital/internet) - can access radio and TV in different ways. Each method has its advantages and disadvantages - AM (low quality, only audio , wide range, mono) or FM (better quality analogue but less range, stereo) or Digital(Digital Audio Broadcast Radios)/ Internet (greater access, best range as it is worldwide but quality is dependent on you)

TV (analogue/digital/internet) - Digital signals can be transmitted by cable, satellite or radio transmitter - analogue (no longer within the UK- lower quality generally)/Digital/Internet signals/ Cable / Satellite