Digital Subscriber Line (DSL)

1
Digital Subscriber Line (DSL)

• Mary L. Pretz-Lawson
• Assistant Director, Computing Services
• Carnegie Mellon University
• 5000 Forbes Avenue
• Pittsburgh, PA 15213
• 412-268-2642
• mlpl_at_cmu.edu
• www.cmu.edu/computing/dsl

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Carnegie Mellon Statistics

• 4,500 undergrads
• 2,500 grad students
• 900 FT faculty
• 2,000 FT staff
• 66 buildings on 100 acres

• Excels in engineering, computer science, drama,
  business
• 85 of students regularly use computers

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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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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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Carnegie Mellon Remote Access

• 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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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
  Verizons network (ARG!)
• Computing Services Help Center takes trouble calls

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DSL Monthly Price Ranges in Western Pennsylvania

• ADSL (incl ISP)
• -640K x 90K _at_40-50
• 1.6M x 90K _at_90-100
• 7.1M x 680K _at_175-190
• Install 0-99
• Modem 0-250

• SDSL (incl ISP)
• 128K _at_55-100
• 384K _at_75-150
• 768K _at_100-175
• 1.544M _at_200-400
• Install 200-400 including modem

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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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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
• doesnt always translate to best service/support

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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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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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...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 DSL-Lite
  for longer distances
• Business-grade SDSL with service level agreements

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Carnegie Mellon DSL Futures

• 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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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