2.7 - Internet Connection Types

Question 1

Cable Modem

Answer 1

• Broadband
• Transmission across multiple frequencies
• Different traffic types
• Data on the “cable” network
• DOCSIS (Data Over Cable Service Interface
Specification)
• High-speed networking
• 4 Mbits/s through 250 Mbits/s are common
• Gigabit speeds are possible
• Multiple services - data, voice

Question 2

DSL Modem

Answer 2

• ADSL (Asymmetric Digital Subscriber Line)
• Uses existing telephone lines
• Download speed is faster than the upload speed
(asymmetric)
• ~10,000 foot limitation from the central office (CO)
• 52 Mbit/s downstream / 16 Mbit/s upstream are
common
• Faster speeds may be possible if closer to the CO

Question 3

Dialup

Answer 3

• Network with voice telephone lines
• Analog lines with limited frequency response
• 56 kbit/s modems
• Compression up to 320 kbit/s
• Relatively slow throughput
• Difficult to scale
• Legacy systems, network utility
• May be difficult to find a modem

Question 4

Fiber

Answer 4

• Fiber optics to the home - high speed networking
• Converged services - Voice, Video, Data
• Enhanced features
• Hundreds of HD channels
• 1 Gbit/sec Internet access
• 1 Terabyte of cloud storage
• 2 Terabyte DVR

Question 5

Satellite Networking

Answer 5

• Communication to a satellite
• Non-terrestrial communication
• High cost relative to terrestrial networking
• 50 Mbit/s down, 3 Mbit/s up are common
• Remote sites, difficult-to-network sites
• High latency - 250 ms up, 250 ms down
• High frequencies - 2 GHz
• Line of sight, rain fade

Question 6

ISDN - Integrated Services Digital Network

Answer 6

• BRI – Basic Rate Interface (2B+D)
• Two 64 kbit/s bearer (B) channels
• One 16 kbit/s signaling (D) channel
• PRI – Primary Rate Interface
• Delivered over a T1 or E1
• T1 – 23B + D
• E1 – 30B + D + alarm channel
• Commonly used as connectivity from the PSTN
to large phone systems (PBX)

Question 7

Cellular Networks

Answer 7

• Mobile devices - “Cell” phones
• Separate land into “cells”
• Antenna coverages a cell with certain frequencies
• Tethering
• Turn your phone into a wireless router
• Mobile hotspot
• Standalone devices
• Use your phone for other things

Question 8

Line-of-Sight Services

Answer 8

• Line-of-sight
• Visual path between antennas - high frequencies
• Common in metropolitan areas
• Cover many homes simultaneously
• Also options for non-line-of-sight - lower frequencies
• WiMAX networking
• Worldwide Interoperability for Microwave Access
• Wireless high-speed Internet access