Zusammenfassung der Ressource
3j - Broadband Connections
- ADSL
- Asymmetric Digital Subscriber Line
- Uses a range of frequencies on
exsiting copper and telephone cables
- Has the largest range of frequency for donwloads
- Quicker to download files
than to upload files.
- Bandwidths are typically either 4, 8, 20 or 24 Mbps
- Factors affecting bandwidth
- Distance from exchange
- Interferance from AM radio
- Other devices connected to phone line
- Electrical interferance
- Used in homes, not businesses
- Low upstream bandwidth
- Bottlenecks
- Cable
- Infrastructure is fibre optic, therefore
higher bandwidths are available
- Typical bandwidths are 20 or 50 Mbps
- It is asymmetric
- There are contention ratios, but it is less than ADSL
- It is used by cable TV companies
- Wireless
- It uses mobile telephone networks
- Can connect a laptop of PC by using:
- Mobile phone internet connection sharing
- Mobile broadband dongle
- Mobile phone WiFi hotspots
- It is asymmetric
- It is dependant on availability of signal
- Cost plans can vary
- Unlimited
- Per Mb downloaded
- Leased Line
- Point to point connection
- Is expensive to install
- No contention ratios
- It is symmetric
- So is useful for extranet access
- Satellite
- It is used in remote areas
- Ships
- Counrtyside
- Desert
- One way satellite
- Satellite for dowload
- Telephone for upload
- Two way satellite
- Uses satellite for both upload and download
- Asymmetric
- Geosynchronous satellite
- Latency of about 0.7 seconds
- OK for standard apllications
- Problematic for interactive apllications
- Line of sight is required