Zusammenfassung der Ressource
3j Broadband
- Asymmetric Digital
Subscriber Line (ADSL)
- Uses existing copper telephone line
- Small amount of frequency left for phone call,
some for upstream and more for downstream
- O- Used in homes as no extra
cable installation is needed
- Asymmetric with downstream
having the greater bandwidth as it
is used for downloading more.
- X- Not suitable for businesses which upload more
- X - Need to be close to a telephone line
- X - Electrical interference and other devices
such as fax machine may reduce bandwidth
- X- Distance from telephone exchange,
and interference from AM radio
stations can decrease bandwidth.
- Cable
- Provided by cable TV companies
- O- Mainly fibre optic -higher bandwidth available
- Asymmetric
- 50Mbps downstream for businesses (20Mbps for homes)
- X- Maybe a bottle neck in the fibre optic cable
connecting a street's switch to the ISP, where
many households are using the same cable.
- Wireless
- 3G can provide 14.4Mbps downstream and 5.8Mbps
- 4G (LTE) can provide 8-30 Mbps
- Used for mobile devices, enables video
calls and high bandwidth internet
- X- Requires a good signal
- Leased Line
- Only between two locations
- O- No connection ratios
and guaranteed bandwidth
- X- Very expensive, installed just for organisation
- Symmetric
- e.g. "Grid for Learning"
- Satellite
- Used in remote area with no
physical/wireless connections
- Two-way satellite broadband allows downloading and
uploading of data through satellite connection.
One-way needs a telephone line to upload.
- Uses Geosynchronous satellites about
37,000km above the earth. Latency of about
0.7 between data being sent and received.
- X- Impractical for interactive applications
e.g. online gaming/ video conferencing
- X- Line of sight required
- Asymmetric: upstream
and down stream have
different bandwidth