Transcript DSL & Case Study of UCD

DSL & Case Study of UCD
Introduction
Comparison, DSL & Alternative
Performance
Provider & Users & Problems
Case Study
DSL(Digital Subscriber Line)
• A new technology for bringing highbandwidth over copper telephone line.
• A service which allows you to use internet
and phone in the same time
• A service which allows you connect to ISP
without changing from analog to digital and
from digital to analog.
Type of DSL
• ADSL
Asymmetric Digital Subscriber Line
1.544 to 6.1 Mbps downstream;
16 to 640 Kbps upstream
• CDSL
Consumer DSL from Rockwell
1 Mbps downstream; less upstream
18,000 feet on 24 gauge wire
Type of DSL
• HDSL
High bit-rate Digital Subscriber Line
1.544 Mbps duplex on two twisted-pair lines
2.048 Mbps duplex on three twisted-pair lines
12,000 feet on 24 gauge wire
Type of DSL
• SDSL
Symmetric DSL
1.544 Mbps duplex (U.S. and Canada); 2.048
Mbps (Europe) on a single duplex line
downstream and upstream
12,000 feet on 24 gauge wire
By Performance and Cost
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Digital Subscriber Line (DSL)
Analog dial up modems
Cable Modem
Satellite Access
Integrated Services Digital Network (ISDN)
DSL
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Provide higher data rate
SDSL, ADSL, VDSL
Differences in wire gauge effects performance
Impulse noise and disturbances affect transmission
rate
• Maximum length< 2000
• Cost: relative to the performance $40-875/ month
(plus $110 installation fee)
Analog Dial up modem
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Quality of line is good
Most for individual PC users
The problems caused by congestion
Cost: Cheap cost and compatibility
Cable Modems
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Primary competitor to DSL
Used primary for residential Internet access
Always on and high speed Internet access
Two types: HFC and one-way modem
Upgrade line is expensive
Basic structure is different from DSL
Cost: $ 40-60/ month ($100-175 install fee)
Satellite access
• Slow and hassle setup with DBS
• Priced services are receive only
• Cost: $179-229 (Install), $350 (dish and
modem)
• Service fee: $20-25/month
ISDN
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Like DSL, gives 3 data channels
Widely available
AO/DI is useful for low bandwidth
Complex
Cost: $125-400 (install and setup), $20-80
(service)
Performance – How it works
• Traditional Phone service
- Analog signal
• Ordinary modems (56K, ISDN)
- Analog changes to Digital
• DSL
- Digital to Digital
- Use your phone and PC on the same line and at
the same time
Performance – How fast it is
Dependent on
• The Distance
• The Quality of the line
• The Price (600k)
• The Quality of your provider’s connection
to the Internet (routers, backbone)
Performance – How fast it is
• Download (25MB under 3 min)
• Browse (25webpages in 13 sec)
TYPE OF FILE
28.8
DATA
LENGTH KBPS
MODEM
ISDN DSL - 384 DSL - 1.5
128 KBPS KBPS
MBPS
25 web
2.5MB
pages with
text and
graphics
12 min
2.5 min
52 sec
13 sec
A 20second
video
37 min
8.5 min
2.75 sec
43 sec
120 min
26 min
8.5 min
2.2 min
8MB
Download 25MB
software
Major DSL Providers in Colorado
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AT&T
Concentric
Covad
Flashcom
JATO: Serving in
Boulder.
• MCI/UUNet
• Northpoint
• Rhythms
• US West: The
Largest DSL
Provider in Colorado
• Verio
Problems in DSL for the User side
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Regulation
Local Phone company requires installation
of new phone line.
"Line Sharing" will be most likely passed in
November, 2000.
Bureaucracies and Mergers in RBOC
GTE and Bell Atlantic
WorldCom and MCI
AT&T and British Telcom
Problems in DSL for the User side
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Time Issue for setting up DSL
DSL: 24 - 48 hours
T-1: 4 hours
Management Capability in DSL
Disaster recovery
Redundancy and Performance
Monitoring capabilities
Problems in DSL for the User side
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Security Issue of DSL
Pacific Bell case
"Anybody could easily access to his
confidential files because his PC has
a file-sharing feature."
Solution 1: Security Software
Solution 2: Education about Internet
Security
Background
• Mainly use Dial-Up networks
• 15 T-1; 23 connection lines; 53 Kbps
• Only 33.3 Kbps for actual
Why Implement DSL, What Kind of DSL
• Faster than ISDN
• Cheaper than Cable Modem
• Implementing ADSL; 640 Kbps downstream and 256
Kbps upstream
With Whom and How Much
• US West
• Lease more 3 Mbps on ATM separate pipe
of DSL
• Leasing cost around $1,000 a month
• More manpower for clerical works not
technical supports
• Only two weeks to implement DSL
DSL Network Configuration in UCD
• UCD is located far from its local TeleCo 4
km.
• 18,000 feet from the TeleCo
• UCD uses ATM modems
• UCD uses Bridging and Static IP addressing
mode not DHCP and Dynamic IP
addressing mode
How It Work
DSL Network Configuration in
UCD
Home
DSL Circuit
IP address information:
- 132.194.x.x, class B, belonging to
UCD
- 255 subnets for the whole campus
- 4-5 subnets for DSL services
DSL
ATM
Internet
OC-3, 155
Mbps (3Mbps
PVC that
UCD is using)
ATM
To Internet
75 Mbps, 25
Mbps
reserved for
UCD
To match IP address with the
PVC number, for example,
132.194.200.3 for 1/100 PVC
UCD
WAN
Campus
To the
Router
campus
FRGP Router
(Front Range Giga Pop)
Difficulties and Benefits for Users
• Difficulties in DSL installing process
• Solved by providing the instruction
• Major Benefits:
– Faster Connection,
– Always On,
– No Downtime
Procedure for Users to Install DSL
• Contact US West (1-877-236-8169) and
identify yourself as a UCD user
• Order DSL service from US West (Line
Connection)
• Go to CINS office (North Classroom 2514)
• Fill out the form
• Wait for and install devices provided by US
West (DSL Modem, Microfilter, etc.)
Information provided by
• Dr. Randy Hagan
- A Principal Software
Programmer under the
computing, information
and network services in
UCD
• Location: 1200 Larimer
Street, NC 2506
• Office: (303) 556-6100
• Internet:
Randy.Hagan@cudenv
er.edu