Internet Access Wired Networks Quiz

Internet Access Wired Networks

• Public Switched Telephone Network (PSTN): Historically, most phone connections used the PSTN. Most calls are digital, except for the local loop (between phone and switching office). In the local loop, data is analog. Digital data needs conversion to analog via a modem. The modem connects to the computer via serial port or USB. Data is converted back to digital at the receiving end by another modem.

Dial-up Internet Access

• Dial-up Internet Access: Uses existing PSTN lines to connect to an Internet Service Provider (ISP). A modem is required. Dial-up speed is 56Kbps.

Digital Subscriber Line (DSL)

• Digital Subscriber Line (DSL): A family of technologies providing internet access via a local telephone network. Connects to the internet via a regular modem, local area network, cable modem, or DSL connection. DSL is often understood, in marketing terms, as Asymmetric Digital Subscriber Line (ADSL).
• DSL Service Delivery: Delivered simultaneously with wired telephone service. Uses higher frequency bands for data.
• DSL Data Rate: Consumer DSL services typically range from 256 kbit/s to over 100 Mbit/s downstream (to customer). Upstream rates are lower. 1 Gbit/s rates have been achieved in trials.
• DSL Disadvantages: Performance is better the closer you are to the central office. Signal weakens further away. Receiving data is faster than sending data. Not available everywhere.

Integrated Services Digital Network (ISDN)

• Integrated Services Digital Network (ISDN): High-speed telecommunications support using existing infrastructure. Integrated digital phone service provided by regional/national phone companies.

• ISDN Concept: Integrates analog/voice data with digital data over the same network.

• ISDN Service Levels: Basic Rate Interface (BRI) for home/small enterprise. Primary Rate Interface (PRI) for larger users. Both include B-channels (data, voice) and D-channels (control/signal).

• ISDN Popularity: Now less popular in areas with DSL or cable modem options.

• ISDN Usage: Requires ISDN modem or adapter at both ends of transmission (for user and provider).

• ISDN Modems: Internal or external configurations. Some throughput loss when using maximum bandwidth via serial ports which typically only allow up to 115 Kbps.

Data Transfer Rate (ISDN)

• Basic Rate Interface (BRI): Two 64 Kbps B-channels and one 16 Kbps D-channel. Supports up to 128 Kbps service
• Primary Rate Interface (PRI): 23 B-channels and one 64 Kbps D-channel (US), 30 B-channels, and one 64 Kbps D-channel (Europe).
• ISDN Speed Comparison: Slower than LAN, but faster than analog phone lines. ISDN connections establish quickly, usually within 2 seconds compared to minutes for analog modems. Digital nature eliminates analog modem process.

TV-Cable Networks

• Cable Modems: Devices enabling PC connection to cable TV lines. Offers data rates significantly higher than 56Kbps modems and ISDN. Typically, 1.5- 150 Mbps.
• Shared Bandwidth: Network segment users share bandwidth, affecting performance.
• Cable Modem Connections: A cable modem has two connections: one to a cable wall outlet and the other to a PC.

Internet Access from Cable TV Providers

• Cable Internet Access: Offered by cable TV companies, using the same cable lines as TV signals.
• Bandwidth Share: Users share bandwidth, potentially impacting performance.
• Security Concerns (Cable): Security risks can exist due to shared network segments.
• Business Applications (Cable): Cable internet access may not be practical in offices lacking cable TV wiring. Cable internet is increasingly becoming a business alternative to DSL.