Transcript Digital Subscriber Line (DSL)

Digital Subscriber Line
(DSL)
Mary L. Pretz-Lawson
Assistant Director, Computing Services
Carnegie Mellon University
5000 Forbes Avenue
Pittsburgh, PA 15213
412-268-2642
[email protected]
www.cmu.edu/computing/dsl
Carnegie Mellon Statistics
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4,500 undergrads
2,500 grad students
900 FT faculty
2,000 FT staff
66 buildings on 100
acres
10/11/00
• Excels in engineering,
computer science,
drama, business
• 85%+ of students
regularly use
computers
Mary L. Pretz-Lawson, Carnegie
Mellon
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Computing & Communications
• 8,400 telephone lines with Verizon (Bell Atlantic)
Centrex on Nortel DMS switch
• 75% IBM Type; 25% Cat 5 cabling
• 70% of traffic is IP; 30% is IPX and AppleTalk
• Cisco 7500s in bridged network moving to routed
network (70% complete)
• Installing Gigabit Ethernet backbone using Cisco
6509s with redundant core (70% complete)
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Mary L. Pretz-Lawson, Carnegie
Mellon
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Internet Connectivity
• Commodity connection
– ATM OC3 link via Pittsburgh Supercomputing
Center
– 45 Mbps total to ATT, SurfNet, Sprint, UUNet
• vBNS connection
– OC3 link via School of Comp Science
• Abilene connection
– OC3 link to be upgraded to OC12 link
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Mellon
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Carnegie Mellon Remote Access
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300+ v.90 digital modem pool
Early DSL trials starting in 1996
Production DSL service in April 1999
600+ DSL users today, 575 with Verizon, 25
with North Pittsburgh
• CMU is ISP with ATM (Verizon) or frame
(NPTC) connection to carrier
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Mary L. Pretz-Lawson, Carnegie
Mellon
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ADSL - Splitting the Bandwidth
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Carnegie Mellon as DSL ISP
• Issue CMU IP addresses
• Network throughput 6 times faster on CMU
DSL vs Verizon DSL
• Configure PVCs and router in compliance
with Verizon’s network (ARG!)
• Computing Services Help Center takes
trouble calls
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Mellon
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DSL Monthly Price Ranges in
Western Pennsylvania
• ADSL (incl ISP)
– -640K x 90K @$40-50
– 1.6M x 90K @$90-100
– 7.1M x 680K @$175190
• Install $0-99
• Modem $0-250
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• SDSL (incl ISP)
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128K @$55-100
384K @$75-150
768K @$100-175
1.544M @$200-400
• Install $200-400
including modem
Mary L. Pretz-Lawson, Carnegie
Mellon
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State of DSL in Western PA
• Coverage
– varies by provider
– know your key areas (Squirrel Hill)
• Pricing = lower costs in future? YES!
– Increased competition and lower cost cable
modems
– FCC ruling on requiring RBOCs to line share
with DSL providers
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Mary L. Pretz-Lawson, Carnegie
Mellon
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…State of DSL in Western PA
• Target Markets
– is provider focusing on consumer or business
applications?
– Internet surfing vs telecommuting vs research
vs remote office requirements
• Market Share
– usually translates to broadest coverage
– doesn’t always translate to best service/support
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Mary L. Pretz-Lawson, Carnegie
Mellon
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…State of DSL in Western PA
• Ordering/Support
– some providers still using phone/FAX ordering
– most moving to online, web-based ordering and
trouble tickets
• Service Level Agreements
– rarely available but important service issue
– support infrastructures not yet well developed
– key area for differentiation between providers
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Mary L. Pretz-Lawson, Carnegie
Mellon
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Digital Subscriber Line Futures
• Verizon has turned up residential service in
most COs
• Facility-based providers and resellers
offering alternate DSL services
• Competitive DSL providers & ILECs
forging liaisons (Verizon and Northpoint)
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Mary L. Pretz-Lawson, Carnegie
Mellon
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...Digital Subscriber Line Futures
• Standards still evolving (CAP vs DMT
modulation scheme)
• Splitterless technology with user-installed
line filters
• DSL over fiber facilities; lower speed DSLLite for longer distances
• Business-grade SDSL with service level
agreements
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Mary L. Pretz-Lawson, Carnegie
Mellon
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Carnegie Mellon DSL Futures
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New part time DSL Technical Assistant
Outsourcing ISP functions
Local peering with ISPs to minimize hops
VPN to provide CMU IP addresses
ISP takes trouble calls
Conversion to new service model in
summer 2001
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Mary L. Pretz-Lawson, Carnegie
Mellon
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Other Broadband Offerings
• Wireless local loop access alternatives
• Cable modems race with DSL for market share
– some areas need cable plant upgrades
• Satellite-based DSL services appearing
• Fiber to the home coming soon?
• CLECs pursuing Voice over DSL to small/medium
businesses
– 16 voice lines + high speed data = 1 copper pair
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Mary L. Pretz-Lawson, Carnegie
Mellon
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