Download Chapter 1 - Introduction

Access and Interconnection
Technologies
Asst. Prof. Chaiporn Jaikaeo, Ph.D.
[email protected]
http://www.cpe.ku.ac.th/~cpj
Computer Engineering Department
Kasetsart University, Bangkok, Thailand
Adapted from the notes by Lami Kaya, [email protected]
© 2009 Pearson Education Inc., Upper Saddle River, NJ. All rights reserved.
Access Technology

Internet access technology


A data communications system that connects an
Internet subscriber to an ISP (Internet Service
Provider)
Such as a telephone company
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Upstream vs. Downstream

Most Internet users follow an asymmetric
pattern



a subscriber receives more data from the
Internet than sending
Downstream to refer to data traveling from
an ISP in the Internet to a subscriber
Upstream to refer to data traveling from a
subscriber to an ISP
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Upstream vs. Downstream
Downstream
Upstream
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Narrowband vs. Broadband

Both refer to access technologies



Narrowband   128 kbps
Broadband   1 Mbps
Exact boundary is blurry
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Narrowband Technologies




Dialup telephone connections
Leased line circuits (via modems)
Fractional T1 data circuits
ISDN
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Broadband Technologies



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Digital Subscriber Line (DSL)
Cable modem
Wireless access (GPRS, EDGE, 3G)
T1 (or higher) data circuits
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Local Loop

Local loop describes the physical connection
between a telephone company Central Office
(CO) and a subscriber


Consists of twisted pair and dialup call with 4
KHz of bandwidth
It often has much higher bandwidth

A subscriber close to a CO may be able to handle
frequencies above 1 MHz
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Digital Subscriber Line (DSL)

DSL is one of the main technologies used to
provide high-speed data communication services
over a local loop

the set is collectively referred to by the acronym xDSL
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Bandwidth Division in ADSL
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ADSL Installation
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Recent DSL Technologies

HDSL – High-bit-rate DSL
VDSL – Very-high-bit-rate DSL
SDSL – Symmetric DSL
ADSL2
ADSL2+

See also



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Source: AWARE. ADSL2 and ADSL2+
The new ADSL standard.
http://en.wikipedia.org/wiki/Digital_subscriber_line
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Cable TV Networks

Started as a video service provider, then
moved to the business of Internet access
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Hybrid Fiber-Coaxial Network


Or HFC
Bidirectional communication is achieved
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Data Transfer over CATV




Standard: DOCSIS (Data Over Cable Service
Interface Specification)
Division of coaxial cable band by Cable TV
Theoretical downstream data rate is 30 Mbps
Theoretical upstream data rate is 12 Mbps
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Cable Modem
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Cable Modem Transmission System

Or CMTS
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Fiber To The X

Optical broadband network architectures
Fiber-to-the-node
Fiber-to-the-curb
Fiber-to-the-building
Fiber-to-the-home
Source: Wikipedia
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Wireless Technologies

Imagine a farm or remote village many miles
from the nearest city


The twisted pair wiring used to deliver telephone
service to such locations exceeds the maximum
distance for technologies like ADSL
Local loop technology may not work on all
lines
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Wireless Technologies



3G/4G (Third/Fourth Generation) cellular
telephone services
WiMAX
Satellites
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WiMAX Overview
ISP
Internet
Backbone
Cell-like WiMAX towers
Line of sight
transmission
Non line of sight
transmission
Home WLAN
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Broadcast Satellite Systems




More BW than dialup
Reach arbitrary locations
Long delay
Downlink is good, Uplink is expensive

alternative uplink (dialup)
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