Broadband Access Networks and Services

1
Broadband Access Networks and Services
EE4541.759 Spring 2004

• Chapter 6
• Full Service Access Networks
• Byeong Gi Lee
• Seoul National University

2
6. Full Service Access Network

• Evolution of Services and Networks
• Toward FSAN
• FSAN
• Organizations of FSAN
• (Case Study) Time Warners Pegasus
• Evolution of BAN

3
Structure of Access Network

• ADSL Asymmetric Digital Subscriber Line
• DBS Direct Broadcast Satellite
• FTTC Fiber To The Curb
• HFC Hybrid Fiber Coaxial
• LMDS Local Multipoint Distribution System
• MMDS Multi-channel Multipoint Distribution
  System
• MSO Multiple Service Operator

Digital DBS
Fiber or Wireless
MMDS/LMDS
LMDS only
Hub Station
DBS STB/ MMDS/LMDS STB
64Kbps
ISDN Adaptor
ISDN Line
MSO /CO
Analog Modem
56Kbps
ADSL Modem
6Mbps
Home Terminal
640Kbps
30Mbps
Coax
Cable Modem
Fiber
HFC
3Mbps
ONU
Coax or Copper
VDSL Modem
Fiber
52Mbps
FTTC/FTTO
3Mbps
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Access Network Architecture (1)

• Diverse access and backbone infrastructure

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Evolution of Services

• Three independent streams of services
• Voice communication
• telephone service -gt wireless mobile, multimedia,
  videophone, video conference, telecommuting,
  distance learning, telemedicine
• Video distribution
• television service -gt terrestrial, cable TV, DBS,
  MMDS, LMDS, HFC, VOD, MPEG Video, ..
• Interactive data
• computer data service -gt data, e-mail, Internet,
  WWW, teleshopping, telegame, digital library
  service

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Evolution of Networks

• Three independent networks
• Telephone network
• -gt PSTN, ISDN, PCN, SONET/SDH, BISDN/ATM,
  WDM/optical networks
• Broadcasting network
• -gt TV, CATV, DBS/satellite, MMDS, LMDS, HFC
  networks
• Local area network
• -gt LAN, MAN, WAN, FDDI, DQDB, Fast Ethernet,
  Gigabit Ethernet

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Evolution of Services and Networks
Interactive Multimedia, Broadband Network
LMDS
DBS
DMB
VOD, HFC
HPI / 802.16
Video services
Bandwidth
WDM / optics
Fast, Gigabit Ethernet
FTTx
DQDB MAN
SONET / SDH
ISDN, BISDN
FDDI LAN
Data services
Voice services
POTS PSTN
Ethernet LAN
Cellular Phone
Interactivity
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Toward FSAN (1)

• Three Functional Domains
• Service provider domain
• application services, content providers, etc.
• Network provider domain
• PSTN, PSDN, Internet, ISDN, BISDN, HFC Net, etc
• Service user domain
• voice, video, data terminals,
• network termination, subscriber terminal unit
• home network

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Toward FSAN (2)

• FSAN Full Service Access Network
• Access that are intended to provide everything
• Broadcast TV, Internet access, VoD, voice
  telephony
• FTTx, cable, xDSL
• Would offer the lowest-cost alternative for
  subscribers to receive all services
• Would be easy for the subscriber to use single
  interface to a variety of services
• Would tend to reduce customer churn
• Consumer would be more reluctant to part with a
  single service if that service came in a bundle

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Toward FSAN (3)

• Three domains for full-service access network

PSTN PSDN ISDN
Control network
Voice terminal
Service gateway
Application servers, content providers, ISPs
Headend node
Remote node
Video terminal
NT/STU
Access network
Internet
Core network
Data terminal
Management network
LAN
Service networks
BISDN, SDH/SONET
Service provider domain
Service user domain
Network provider domain
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Toward FSAN (4)

• Subscriber Access Network Aspect
• Connecting head-end node, central office, remote
  node, network termination
• Bandwidth broadening, easy connection to trunk
  equipment, major interests
• TP-based, HFC-based, FITL-based, wireless-based
• FSAN would be ADSL, HFC, FTTC/VDSL, PON or
  wireless connections
• In practice, FTTH/PON, FTTC/VDSL, HFC

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Toward FSAN (5)

• Integrated architecture of subscriber network

ADSL
Headend node (Headend, central office)
Twisted pair
HFC
HFC OLU
ONU
Optical fiber
Coax cable
FTTC/VDSL
OLU
ONU
Twisted pair
PSTN ISDN BISDN
PON (FTTH)
OLU
Wireless
Internet
LU
RN
Fiber, coax, microwave
Radio
OLU Optical Line Unit
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Toward FSAN (6)

• Illustration of HFC-based FSAN

ONU
Subscriber premises
Headend/central office
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Organization of FSAN (1)

• FSAN initiatives established in 1995 by 7 major
  telecom operating companies to accelerate
  commercial deployment of optical access systems.
• Full Service Optical Access Network (OAN)
• FSAN Operations and Maintenance (OAM) 
• Full Service VDSL(FS-VSDL) was launched in July
  2000 as a sub-committee of FSAN to define a
  competitive end-to-end video-centric full service
  network specification

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Organization of FSAN (2)
16
FSAN Board Members
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FSAN vs Standard Organizations (1)
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FSAN vs Standard Organizations (2)

• Relation with other standard bodies

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FSAN - OAN

• The Optical Access Network Working Group
• Tasked with identifying and forwarding issues
  related to optical and other transport networks,
  and liaising with the SG15/Q2 of the ITU
• Responsible for studies relating to the optical
  access network technology and transport.

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FTTx for FSAN-OAN
FTTB
FTTC
FTTO
ADSL/
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FSAN - OAM

•  The Operations and Maintenance Working Group
• Tasked with identifying and forwarding issues
  related to operations and maintenance for the
  FSAN, and liaising with the SG4/Q14 (TMN) of the
  ITU
• Responsible for studies relating to the
  management of telecommunication services,
  networks, and equipment using the
  telecommunication management network (TMN)
  framework, of information modeling for broadband
  networks and ATM network elements in particular

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FSAN OAN and OAM

• Scope

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FSAN OAN - ITU-T Rec.
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FSAN VDSL (1)

•  FSAN FS-VDSL Focus Group
• Mission is to accelerate standardization,
  implementation and deployment of a VDSL-based
  network optimized for delivery of a full set of
  integrated services, including entertainment
  video, high speed data, and voice utilizing
  existing copper twisted pair loop infrastructure.
  
• It operates an independent site at www.fs-vdsl.net

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FSAN - VDSL (2)

• Launched in July 2000 as a sub-committee of FSAN
  to define a competitive end-to-end video-centric
  full service network specification applicable to
  Telcos
• Facilitate smooth evolution of DSL platforms
• Re-use existing standards and fill gaps
• Encourage end-to-end interoperability
• Promote global competitive deployment
• Downstream to international standards
• Adopted as an ITU-T Focus Group in Oct. 2002

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FSAN - VDSL (3)

• Rationale for optical distribution network
• No attempt to define optical distribution network
• References FSAN work for the optical
  characteristics
• ONU and OLT expected to originate from the same
  vendor in early VDSL deployments
• Allows vendors to innovate ONU-OLT architecture
  and functionality (e.g., multicasting) to reduce
  cost
• Allows to avoid choice between PON and pt-pt
• Pragmatic position which reflects the ongoing
  debate within telcos on their future deep fiber
  strategy
• PON vs. pt-pt
• Gigabit Ethernet vs. SONET-SDH/ATM

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Case StudyTime Warner Pegasus (1)

• Not an FSAN in strict sense
• Does not attempt to offer telephone service
• Carries broadcast video, video, video on demand,
  and IP connectivity on a single network
• Uses ATM in the Core Network, and MPEG and IP in
  the distribution network
• Designed to provide services for
• analog TV, digital TV, VoD, and two-way data
  service for control purposes

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Case StudyTime Warner Pegasus (2)

• Forward Application Transport (FAT)
• 6MHz channel encoded using QAM 64 or QAM 256
• VoD, broadcast TV
• Forward Data Cannel (FDC)
• 1MHz channel encoded using QPSK to yield a T1
  data channel in the forward direction
• Reverse Data Cannel (RDC)
• QPSK-modulated 1MHz T1 data channel in the
  reverse direction
• Compatible with the DAVIC signaling specification

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Case StudyTime Warner Pegasus (3)

• FDC/RDC provides the following
• Two-way real-time signaling for VoD
• Delivery of set-top authorization messages
• Network management of the set-top box
• IP connectivity for set-top applications, such as
  Web browsing

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Case StudyTime Warner Pegasus (4)

• Analog broadcast is received at the head end and
  is retransmitted on a FAT channel
• Digital broadcast is received at the head end in
  MPEG packets with QPSK modulation
• Satellite delivery is encoded in QPSK
• Cable delivery is encoded using QAM 64

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Case StudyTime Warner Pegasus (5)

• Broadcast Cable Gateway (BCG)
• Remodulates and re-encrypts the satellite digital
  video into a form standardized on cable networks
• Interactive Cable Gateway (ICG)
• Enables the integration of video with data into
  the FAT channels
• Required to embed Web content into a program or
  to enable electronic commerce if it needs video
• Data Channel Gateway (DCG)
• Provides a two-way real-time data communication
  path

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Case StudyTime Warner Pegasus (6)

• Pegasus Full-Service Network

Analog
Broadcast Cable GW
Hybrid
Pegasus
Fiber
Set-top
Coax
Interactive Cable GW
Digital Network Control System
Core
ATM
Data Channel GW
Application
Network
Server
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Case StudyTime Warner Pegasus (7)

• Pegasus Set Top

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Equal Access to Multiple Networks (1)

• Work-at-home requirements
• Connection must be authenticated by the corporate
  network
• Work-at-home user should be a part of the
  corporate IP numbering plan rather than the
  Access Network numbering plan
• Approach that a single Access Network interface
  can accommodate both users
• Tunneling
• Encapsulation of a users data packet within
  another packet
• L2TP (Layer 2 Tunneling Protocol)

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Equal Access to Multiple Networks (2)

• L2TP (Layer 2 Tunneling Protocol)
• 1. Remote user initiates PPP, and NAS accepts the
  call
• 2. NAS authenticates the remote user using a
  security server
• 3. NAS initiates an L2TP tunnel to the desired
  corporate network
• 4. Corporate gateway confirms acceptance of the
  call and the L2TP tunnel
• 5. NAS logs acceptance
• 6. Security server authenticates the remote user
  and accepts or rejects the tunnel
• 7. Corporate gateway exchanges PPP information
  with the remote user. An IP address is assigned
  by the corporate gateway to the remote user
• 8. End-to-end data is tunneled between the remote
  user and the corporate gateway

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Equal Access to Multiple Networks (3)

• L2 Tunneling Protocol

NAS Network Access Server
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Benefits of FSAN

• Reduce to complexity to the consumer
• Reduce overall costs to consumers who want a wide
  variety of services
• Single billing system and customer service
  infrastructure
• Create better account control and reduce customer
  churn

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Challenges of FSAN

• FSN Versus Cell Phones
• Place Bets Up Front
• Many carriers fear that moving to a FSN is an
  all-or-nothing proposition
• Biting Off Too Much
• When optimizing large systems, it is not
  necessarily true that one obtains a globally
  optimal result by optimizing everything at once
• Billing Complexity

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Prognoses (1)

• Service delivery standards by access network

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Prognoses (2)

• Existing access and content providers
• are trying to gauge their own chances of success
  against the competition
• Possible franchise holders
• DBS, MMDS, LMDS, cable, and xDSL services from
  the incumbent and competitive telephone companies
• FTTx services from ILECs and alternative carriers
• Narrowband services
• will be available from the electric utility and
  several telephone companies

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Prognoses (3)

• There will be neither shortage of Access Networks
  nor standardization of applications
• Business consideration
• Success for any single company or technology will
  not be determined by technology characteristics
• Fiber will extend farther into the neighborhoods
  and closer to the end user
• There will be an impact on mass culture

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Prognoses (4)

• Social issues will become more contentious
• Conflict between law enforcement and privacy
• Conflict btw public safety and freedom of
  expression
• Universal service for broadband
• Scope of law enforcement
• There is no best Access Network for all services
• Some technology fits certain content better than
  other
• Success of RBB
• depends on finding the market drivers