Modern Services of Data Network Part I Communication

1
Modern Services of Data NetworkPart
ICommunication
Presented by Dr. Mohsen Kahani Ferdowsi
University of Mashhad kahani_at_um.ac.ir http//www.u
m.ac.ir/kahani
2
Table of Contents

• Ethernet and 10GBE
• Internet Telephony
• WiFi Hotspot
• xDSL Technology
• Fiber To The Home (FTTH)

3
Backbone Architecture Layers

• Network designs are made up of three technology
  layers
• The access layer which is the technology used in
  LANs
• The distribution layer connects LANs together
• The core layer connects different backbone
  networks together

4
Backbone Technologies
5
Fiber Distributed Data Interface (FDDI)

• FDDI backbone protocol was developed in the 1980s
  and popular during the 80s and 90s.
• FDDI operates at 100 Mbps over a fiber optic
  cable.
• FDDI uses both a physical and logical ring
  topology capable of attaching a maximum of 1000
  stations over a maximum path of 200 km. A
  repeater is need every 2 km.
• FDDIs future looks limited, as it is now losing
  market share to Gigabit Ethernet and ATM.

6
FDDI Topology
7
FDDIs Self-healing Rings
8
Asynchronous Transfer Mode (ATM)

• Asynchronous Transfer Mode (ATM) (also called
  cell relay) is a technology originally designed
  for use in wide area networks that is now often
  used in backbone networks.
• ATM backbone switches typically provide
  point-to-point full duplex circuits at 155 Mbps
  (total of 310 Mbps).

9
Ethernet Timeline 

• 1973 Ethernet Invented 2.93 Mbps 
• 1992 10 Mbps Ethernet Available 
• 1994 100 Mbps Ethernet Available 
• 1997 1000 Mbps Ethernet Available 
• 2002 10 Gbps Ethernet
•  

10
FAST ETHERNET

• Fast Ethernet refers to a set of IEEE 802.3
  specifications that provide a low-cost
  Ethernet-compatible LAN operating at 100 Mbps.
• Basic idea is to keep all the old packet formats
  and protocols, just increase the speed.

11

• Specifications
• 100BASE-T4 100 Mbps over twisted pair category 3
  UTP
• 100BASE-TX for category 5 UTP, full-duplex at
  100 Mbps.
• 100BASE-FX for fibre, full-duplex at 100 Mbps.

12
GIGABIT ETHERNET

• Fast is never fast enough
• Migration of fast Ethernet to the desktop created
  bottlenecks at servers and switches.
• Gigabit Ethernet was designed to alleviate this
  congestion by providing faster backbone
  technology.
• The strategy for Gigabit Ethernet is the same as
  for fast Ethernet

13
GIGABIT ETHERNET CONT.

• Define a new medium, but retain the same CSMA/CD
  protocol and frame format as 10 Mbps and 100 Mbps
  Ethernet.
• The transmission medium is optical fibre over
  short distances.
• UTP and STP are also allowed.

14
Gigabit Ethernet Terminology 

• 1000BASE-SX
• Short wavelength specification for Gigabit over
  MMF up to 300 meters
• 1000BASE-LX
• Long wavelength specification for Gigabit over
  MMF up to 550 meters or SMF up to 5 Km
• 1000BASE-CX
• Short haul specification for Gigabit over 4
  conductor coax up to 25 meters
• 1000BASE-T
• Standard that can yield 100 meter distances

15

• Whats new 10 GbE  
• Formally ratified on June 12, 2002
• Ongoing need for more bandwidth
• Designation of bandwidth
• Uses 802.3ae
• 40 GbE on its way

16
10 GE a new Ethernet

• 10 GE designed from the beginning for access to
  long haul networks
• 40 km maximum distance specified by the standard
  
• 1550nm lasers optical amplifiers can be used to
  increase distance over dark fibre
• State of the art 250 km demonstrated in Denmark
  by the EU ESTA project

17
The 10 GE WAN PHY

• 10GE introduces a gateway from LAN to the WAN by
  means of the WAN PHY
• Compatible with existing WAN infrastructure
• Transmission rate
• Encapsulation
• Partial use of the management bits of the
  SONET/SDH frame
• Todays WAN PHY modules use SONET-compliant
  optical components

traditional
Router
OC192
LTE
Router
WAN
LTE
OC192
3R
3R
3R
WAN PHY
WAN PHY
novel
10GE switch/router
10GE switch/router
18
Why native Ethernet long haul?

• More than 90 of the Internet traffic originates
  on an Ethernet LAN
• Data traffic on the LAN increases due to new
  applications
• Ethernet services with incremental bandwidth
  offer new business opportunities to carriers
• See IEEE Communications Magazine, Vol. 42, No. 3,
  March 2004, on additional benefits for both the
  enterprise and the service providers
• Why not native Ethernet ?
• Scalability, reliability, service guarantees
• All of the above are active research areas
• Native Ethernet long haul connections can be used
  today as a complement to the routed networks, not
  as a replacement

19
Demo during ITU Telecom World '03
10 GE WAN PHY over an OC-192c circuit using
lightpaths provided by SURFnet and CANARIE
9.24 Gbps using traffic generators
5.65 Gbps using TCP on PCs
6 Gbps using UDP on PCs
20
Results on the transatlantic 10 GE
Single stream UDP throughput
Single stream TCP throughput

• Data rates are limited by the PC, even for our
  memory-to-memory tests
• UDP uses less resources than TCP on high
  bandwidth-delay product networks

21
WAN PHY over DWDM
Force10 E600
HP Itanium-2
DWDM
Ixia 400T
10 GE WAN
10GE LAN
Force10 E600
Intel Xeon
HP Itanium-2
Ixia 400T
10 GE WAN
10GE LAN
DWDM
Amsterdam
Geneva
HP Itanium-2

• Direct lambda access from the provider is
  required
• The DWDM transceiver card as LTE

22
10GBASE-T Objectives

• Keeping it Ethernet
• Preserve the 802.3/Ethernet frame format at the
  MAC Client service interface
• Preserve min. and max. frame size of current
  802.3 Std.
• Support star-wired local area networks using
  point-to-point links and structured cabling
  topologies
• Keeping it 10 Gigabit Ethernet
• Support full duplex operation only
• Support a speed of 10.000 Gb/s at the MAC/PLS
  service interface
• Compatibility with 802.3
• Support Clause 28 auto-negotiation
• To not support 802.3ah (EFM) OAM unidirectional
  operation
• Support coexistence with 802.3af (DTE Power via
  Ethernet)

23
10GBE Applications
24
10GBE-T Importance

• Faster network link speeds provide new generation
  of systems
• Modular switches and servers
• Backplanes and switch fabrics aggregate to
  support multiple 10GBASE-T ports
• Servers with faster I/O subsystems (i.e. PCI
  Express)
• Low cost solutions are market stimulus
• 10GBASE-CX4 is a step in the right direction, but
  limited reach
• 10GBASE-T
• Addresses PHY costs concerns in Enterprise market
• Enhances reach and conforms to structured cabling
  environments
• Lower cabling costs
• Installation practices are well-known
• Ease of installation
• Cost of termination

25
Comparison of 10GBE GBE
26
10GBE-T Performance

• With the 4 connector model and proposed
  signaling
• 100m on Class F (Cat 7)
• gt 55m on Class E (Cat 6) operating beyond the
  specified frequency range
• 100m on the new cabling being defined by cabling
  standards
• groups (derivative of Class E/Cat 6)
• 20 to 60m on Class D (Cat 5e) was discussed
• Requires operation beyond the specified frequency
  range
• No consensus achieved on extending the
  specification
• Increase in system margin and/or reach are
  possible
• Several techniques have been presented in the
  SG
• Analog signal conditioning
• Alien noise suppression
• Improvements in the cabling specification

27
ATM vs. Switched Ethernet

• ATM is a switched network, but differs from
  switched Ethernet in four ways
• 1. ATM uses small, fixed-length packets of 53
  bytes (called cells). Ethernet frames are
  variable and can be up to about 1 kilobyte in
  length.
• 2. ATM provides no error correction on the user
  data. Switched Ethernet does error correction.
• 3. ATM uses virtual channels instead of the
  fixed addresses used by traditional data link
  layer protocols such as switched Ethernet.
• 4. ATM prioritizes transmissions based on
  Quality of Service (QoS), while switched Ethernet
  does not.

28
Enterprise Backbone Technology Trends

• Organizations are moving to Ethernet-based
  collapsed backbones with switched LANs or VLANs.
• Gigabit Ethernet use is growing.
• FDDI seems to be on its way out.
• ATM, while still popular in WANs, is also losing
  ground to Gigabit Ethernet.
• Taken together, it appears that Ethernet use will
  dominate the LAN and backbone.

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The Ideal Backbone?

• The ideal network design is likely to include the
  following characteristics
• Combined use of layer 2 and layer 3 Ethernet
  switches.
• The access layer (LANs) uses 10/100 Layer 2
  Switches running Cat 5 or Cat 6 twisted pair
  cables (Cat 6 enables the move to 1000BaseT).
• The distribution layer uses Layer 3 Ethernet
  Switches that use 1000BaseT or fiber, Cat 6 or
  Cat 7 TP.
• The core layer uses Layer 3 Ethernet Switches
  running 10GbE or 40GbE over fiber.
• Reliability is also increased in the network by
  using redundant switches and cabling.

30
Internet Telephonyvs.Telephony over Internet
31
Telephony over Internet

• Emulation of Telephony Services on Internet
• dumb end terminals (cable modems)
• 12-digit keypad UI
• transparency of services
• it is important!

• Primary motivation
• cost savings
• non-telcos can enter
• Cost savings are transient
• Whats in it for customers????

32
Branch Office Application
33
Interoffice Trunking Application
                                                 
34
Interoffice Trunking Application
. Interoffice Trunking Application
                                                 
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What is it?
Internet Telephony

• Use your PC as a telephone
• Motivation
• Cost -
• Advanced Services
• Higher fidelity voice
• 3D voice reconstruction
• Integration with calendar
• Complex call management
• Mobility
• Powerful voicemail systems integrated messaging
• Multiparty calls
• Video/whiteboard
• Compression, silence suppression

36
Internet Telephony

• Integrate telephony services with
• web
• email
• instant messaging and presence
• text chat
• interactive games

INTERNET TELEPHONY
37
New Services

• Integration causes service multiplication
• 20 voice services X 20 web services 400
  integrated service possibilities
• not all make sense
• New services revenue opportunities

• Examples
• IM Notify when busy
• subscriber gets instant messages when friends
  telephones (IP or POTS) available
• Call redirect to web
• web page returned instead of busy signal
• Web IVR
• web page of menus, final choice rings phone

38
More Services

• Shared web browsing
• talk and browse jointly
• Transfer to email
• Caller is disconnected and mail tool pops up
• Email call logs
• Unanswered calls cause email notifications

• IM notifications of conference join
• On a conference bridge, instant message indicates
  participant joins/leaves
• Web call-ID
• web page of caller pops up when phone rings

39
Who can get services?

• Advanced services can be offered to PSTN end
  systems too!
• VXML consortium
• technology for providing web content on phone
• allows web services to be exposed

• Speech to text
• email sending
• web browsing
• IM
• Text to speech
• Instant messages

40
How to do it?

• Integrated services integrated server
• SIP server/gatekeeper
• SMTP/IMAP/POP client and server
• Presence and IM server
• Web access
• Conference services access

Intelligent Integrated Communications Server
Directory Services
41
What does it have to do with ISPs?

• IP telephony is point to point
• Looks like data to ISP
• Extra Services!
• Network QoS support
• Processing Services
• Gateway Services
• Database Services
• IN Services

42
Gateway Services

• IP to PSTN
• PSTN to IP
• PSTN to PSTN, IP long distance
• IP to IP, PSTN long distance

ISP NETWORK
GW
GW
PSTN
43
Gateway Services

• IP to PSTN
• Billing - accounts, credit cards, e-cash
• Discovery - based on cost, proximity,
  codec/protocol support, administrator
• Non-locality problem - partnerships billing!

• PSTN to IP
• IP endpoint identification
• IP address
• Speech recognition
• alphabet keys
• telephone numbers
• Telephone Numbers
• International, area code, mixed, 10-XXX access
• Gateway Selection

44
Gateway Services

• IP-PSTN-IP (access bypass)
• use ISP as LEC
• improved voice quality
• Discovery problem
• Proximity of GW to IP address
• Traditional routing?
• Phone connection
• transcode for voice only?
• Modem - IP links-on-demand
• Billing

• PSTN-IP-PSTN (long distance bypass)
• Nearly identical to IP to PSTN case
• Selection of gateway similar to PSTN to IP case
• ISP can now be a long-distance provider - ITSP

45
Gateway Architecture

• Basic HW Components
• PC
• DSP card
• Telephony card (Dialogic, Natural Microsystems)
• Ethernet card
• Gateways are a SOFTWARE problem
• call control, billing, accounting, net protocols,
  management, etc.

46
Gateway Features

• Codecs
• GSM, G.729, G.723, Elemedia, G.728, G.726
• Authentication/authorization
• Accounting
• Protocol compliance - H.323, H.332, SIP
• Management
• Billing
• credit cards, account, debit cards, phone cards,
  SET

• /port
• Telephony termination
• analog, T1, T3, ISDN PRI
• IP termination
• Ethernet, Frame Relay, T1,T3, ATM/SONET
• Routing
• static, database access, polling
• IVR System
• User Profiles
• Bridging

47
Main Vendors

• Lucent Technologies
• Enterprise and Carrier grade gateways
• Vienna Systems
• VocalTech
• Micom
• NetiPhone
• Netspeak

• PhoNet
• Ericsson
• Ascend
• .. Several HUNDRED vendors
• Prediction
• Small players will lose to big, carrier-grade
  capable vendors

48
ITSPs

• Internet Telephony Service Providers
• PSTN to PSTN, IP long distance
• Several business models
• Run gateways, resell service to service providers
• Run gateways and service perhaps partner with
  other such providers, also resell service to
  telcos and small ISPs
• Run service only, lease gateways from resellers
• Run clearinghouse for settlements and billing
  agreements (Planet Telecom)

49
Database Services - User Location

• How to determine IP address of a person you wish
  to talk to
• Dynamic IP addresses make this a very hard
  problem
• Several approaches
• Single database
• Email-based
• Location service provided by your ISP

50
User Location

• Single Database
• User registers with well-known database when
  logging in, unregisters when leaving
• Registration binds a unique identifier (your
  name) to IP address
• To call a person, you query database with
  identifier, and get IP address back
• Model used by H.323 (Gatekeepers)
• Initial model used by most IP telephony software
  - each software maintains its own listing
• Can have global directories - Four11
• Big drawback - requires central directory for
  whole planet - scalable? Who will run it?

• Email based
• Your telephone address is your email address
• You register with a directory server associated
  with your domain
• Other users find your directory server in DNS
• Can then query directory server to get your IP
  address
• Scalable, uses existing infrastructure email
  names mnemonic (usually) portability multiple
  names, single email and telephony identifier

51
Database Services - Voicemail

• Your PC is not connected to Internet 24 hours per
  day
• Via Location Database, ISP knows when you are an
  are not connected - can provide voicemail service
• One method
• Location server directs caller to contact
  voicemail server caller leaves message
• Location server sends you email with a URL
• When you log in, you click on URL - brings you to
  a web page on the voicemail server and gets a
  Java applet
• Applet lets you sort and file messages, play them
  out, forward, rewind, etc.
• Big plus Dont even need IP telephony software
  for voicemail, just email!

52
IN Services

• IN Intelligent Networking
• Existing technology which lets you create
  services in telephone network via direct control
  over switches
• Basic idea - let IP hosts (ISP servers) set up
  services in telephone network
• Examples
• Click-to-dial
• Click-for-faxback
• Click-for-content

53
IN Services

• Click to Dial
• Web page has link to call customer service
  department, and a form entry to fill in your
  phone number
• Click on link - web server instructs telephone
  switches to connect you to customer service
• Your phone rings, then customer service
• Call billed to company
• Click for faxback
• Same as above, except your phone is a fax
  machine, and customer service phone is a fax bank
• Gives you instant access to fax databases

• Click for content
• You wish to listen to an audio file over the
  telephone
• Click on web page, fill in form with telephone
  number.
• Media server (either in PSTN or on Internet)
  calls your telephone
• You control playback via telephone tones and/or
  PC controls

54
How to do it all?

• Lots of protocols involved
• RTP (Real Time Protocol)
• H.323 (ITU Spec for Multimedia Conferencing)
• SIP (Session Initiation Protocol)
• RTSP (Real Time Streaming Protocol)
• LDAP (Lightweight Directory Access Protocol)
• Lots still under development
• Gateway Discovery
• IN Services
• User Location

Skip Details
55
RTP/RTCP

• RTP provides for
• Real time transport
• Resequencing
• Payload type identification
• Intra and Inter media synchronization
• Encryption
• Multicast
• Per User demultiplexing - SSRC
• RTP does not
• Provide QoS
• Require RSVP
• RTP is a framework
• Specific payload formats defined for H.263, etc.
• UDP Port numbers based on application

• Real Time Control Protocol
• RTP port 1
• Used for
• QoS Reporting
• Sender reports packets sent, bytes sent
• Receiver reports (per sender) loss, delay,
  jitter observed instantaneous and cumulative
• Media Synchronization
• NTP and RTP Timestamp correlation
• Loose Session Control
• Hello, Bye messages
• SDES - email, username, CNAME, etc

56
H.323

• Monstrous ITU Specification for Multimedia
  Conferencing
• H.323 is an umbrella - many sub-specifications
• H.225.0 Call control, RAS
• H.245 Capabilities Exchange, Indications,
  Notifications
• H.332 - Large Group conferences
• H.450 - Supplementary Services
• G.711, G.728, G.729, G.723.1 - speech coders
• H.261, H.263 - video coders
• H.246 - Interworking between H.323 and other
  H.XXX standards
• H.235 - Security for H.323 terminals

57
H.323 Elements

• H.323 Terminal
• PC with H.323 software
• MCU
• Multipoint Control Unit
• Mixes audio and video
• MC
• Multipoint Controller
• Performs signaling for centralized conferences
• MP
• Multipoint Processor
• Actual device for mixing audio and video

• Gatekeeper
• Controls sessions
• Performs user location and registration
• Performs admission control
• Reroutes signaling
• Processes RAS (Registration, Admissions, Status)
  from H.323 terminals
• Gateway
• Interface between H.323 systems and other systems
  - PSTN, H.324 (PSTN multimedia), H.320 (ISDN
  multimedia), H.321 (ATM multimedia)

58
H.323 in an ISP Network
TO PSTN
GATEWAY
MCU (MP and MC)
ISP IP NETWORK
POP-IN-A-BOX
GATEWAY
H.323 TERMINALS
TO PSTN
GATEKEEPER
DATABASE STORAGE
59
Basic H.323 Call Flow
60
Session Initiation Protocol

• IETF Standard
• Lightweight multimedia session initiation, call
  control, capabilities exchange, and user location
• Based on http textual, reuses authentication
  mechanisms
• Provides full telephony services call forward,
  transfer, 800,900 style numbers
• Supports personal mobility
• Addressing based on email address
• Uses SDP (Session Description Protocol) for
  expressing capabilities

• Basic methods
• INVITE - ask a user to join a session callee
  responds with accept or reject, along with a slew
  of reason codes
• OPTIONS - obtain capabilities, but dont invite
• CONNECTED - acknowledges acceptance
• BYE - for transfers and session terminations
• REGISTER - Allows a user to register with a SIP
  server

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62
Wi-Fi Hotspot

• A specific geographic location in which an access
  point provides public wireless broadband services
  to mobile visitors.
• Hotspots are often located in heavily populated
  places such as airports, convention centers,
  coffee shops, hotels, and so on

63
HotSpot Motivation

• an increasing trend toward being always on,
  always active, and always connected and
  delivering high-speed data and Internet
  applications to wireless subscribers

64
Wireless Taxonomy
Wireless WANs (WWAN)/Nomadic NetworksHigh power,
long rangeVarious cellular and related
technologies (GSM, GPRS, CDPD, TDMA, etc.)
Wireless LANs (WLANs)Medium power, medium
rangeIEEE 802.11 and similar technologies
Wireless Personal Area Networks (WPANs)Low
power, short rangeBluetooth, HomeRF, IrDA, IEEE
802.15 technologies
PAL/HotspotService
65
Standards IEEE 802
66
Standards IEEE 802 (cont)
67
Standards WWAN 2G/2.5G/3G
68
Technologies - WLANs

• Wireless PHYs
• Spread Spectrum (SS) a wideband radio frequency
  (RF) technique that trades off bandwidth
  efficiency for reliability, integrity, and
  security
• Infrared (IR) technology use very high
  frequencies just below visible light to carry
  data. IR cannot penetrate opaque objects.
  Inexpensive. Limited range.
• CSMA/CA
• Designed to solve hidden node situation in
  wireless communication to prevent packet
  collision

69
Technologies WPANs

• Bluetooth
• A low-cost, low-power, short-range radio link for
  mobile devices and WAN/LAN APs. It offers fast
  and reliable digital transmission of both voice
  and data over the globally available 2.4 GHz ISM
  band
• The raw throughput is 1 Mbps, and the actual data
  rate is 728 Kbps

70
Technologies - WWANs

• Up to now, WWAN architectures have focused on
  voice services or at most low-speed circuit-mode
  data. The plans for the future are to add
  higher-speed data services. Hotspot networks
  continue to be best served by WLANs and WPANs for
  the next two to three years rather than WWANs
• Major cellular architectures include TDMA,
  cdmaOne, GSM/GPRS.
• CDMA2000 and W-CDMA have limited support for data
  services

71
Wireless Internet From a Business Perspective

• Business Users Must Haves
• To be able to Send/Receive and Store messages
  seamlessly from any device.
• Access all available electronic data related to
  their work from most devices.
• Central Network Based Address Book
• Access and Schedule Business and Personal related
  Appointments, Events, Reminders

enterprise
72
What does the enterprise need ?

• Collaborative Wireless Applications that Increase
  Personal Productivity and which are
• Secure and Reliable
• Easy to Deploy Maintain
• Modular to Allow for changes in size and
  technology
• Anywhere, Anyhow, Anytime Access
• Low TCO and Affordable Access

73
Operators Network Environment
Phone
74
What are the Opportunities for Carriers ?

• Offer Collaborative Wireless Internet Solutions
  to the Enterprise market thus allowing them to
• Increase ARPU
• Whether billed directly or via cross billing,
  business users will be forced to connect to your
  services, thus increasing your revenues.
• Increase Customer Loyalty
• As data becomes centric, the companies will be
  less apt to change the storage location
• Operators can target individual business users by
  being taking a complete provider approach
  especially for address book and calendar and file
  storage.

75
Operator Business Models

• Packaging Models, subscription based
• Internet Access bundle
• One broadband connection
• One WiFi WLAN router
• Collaborative Messaging Applications
• Email
• Address book
• Calendar
• File storage
• Optional Interface Customizations to Large
  Enterprises

76
Operator Business Models

• Pay-per-use Models
• Internet Access
• WiFi hotspot prepaid hours
• GPRS connections with billed upon kb transfer
  in/out
• Voice access on per minute usage
• Messaging Applications
• Email, address book, calendar, file storage
  applications are available
• SMS/MMS bundle

77
Digital Subscriber LineTechnologies(DSL)
78
Definition of Terms Used

• DSL stands for Digital Subscriber Line
• High Speed Data
• Subscriber Line
• Upstream Downstream
• Symmetric and Asymmetric
• No Dial Ups necessary

79
Types of DSL Technologies

• Asymmetric DSL (ADSL)
• ADSL Light
• Rate-Adaptive DSL (RADSL)
• ADSL 2
• ADSL 2
• High bit rate DSL (HDSL)
• Symmetric DSL (SDSL)
• Single-pair high speed DSL (SHDSL/HDSL2)
• Very High Data Rate DSL (VDSL)
• Other DSL Technologies IDSL VoDSL

80
ADSL

• Fast Broadband connection
• Always On
• Asymmetric
• Dedicated Channel
• Typical Data Rates in Australia today are
• 1.5 Mbits/s downstream 512 kbits/s upstream
• Typical Reach up to 3 km
• Coexists with POTS (Plain Old Telephone Service)
• ITU-T Recommendation G992.1

81
Equipment Used in ADSL

• Transmission Line
• DSLAM (ATU-C)

• DSL Modem (ATU-R)
• Splitter

82
ADSL Limitations

• Frequency Response
• Crosstalk
• Other Limitation to ADSL Services are
• Bridge Taps
• Loading Coils
• Cable Joints
• RIMS
• Pair Gain

83
ADSL Line Coding Modulation

• What is line Coding
• Line coding techniques used with ADSL
• DMT (DMT) Discreet Multitone Modulation
• The transmission of several narrow sub-channels.
• Divides signals into 247 separate channels at 4
  kHz.
• QAM/CAP (QAM) Quadrature Amplitude and Phase
  Modulation
• Combines two different types of
  modulation amplitude and phase.
• (CAP) Carrierless Amplitude and Phase Modulation.
• Similar to QAM, divides signals into three
  distinct bands.

84
ADSL Frequency Graph
85
ADSL Applications

• Internet based applications
• Online Shopping
• Email
• Streaming Video
• MP3 (music files)
• E-commerce
• Fast file transfer
• Video on Demand

86
Other forms of ADSL

• ADSL Light
• Also known as G.Light and Universal ADSL
• Splitterless
• Lower Outlay Costs
• Lower Data Rates
• ITU-T Recommendation G.992.2

87
Other forms of ADSL cont

• Rate Adaptive DSL
• Essentially the same as ADSL
• Rate Adaptive Modem
• Data rates similar to ADSL
• Non-standard

88
Other forms of ADSL cont

• ADSL 2
• Improves Data Rate and Reach
• Enhanced capabilities
• Power management
• Seamless Rate Adaption (SRA)
• ITU-T Recommendation G.992.3
• ADSL 2
• Double the Downstream Bandwidth

89
HDSL

• History T1/E1
• First DSL Technology Developed
• Largely Installed
• Symmetric Transmission
• 2 3 Pairs

• Data Rates
• Capable distance from exchange
• Does not support POTS
• ITU-T Recommendation G.991.1
• also known as G.hdsl

90
Equipment Used in HDSL

• E1 configuration
• Digital Cross Connect (DCS)
• Transmission Line
• Customer Premises Equipment (CPE)
• Mapping Interface
• HDSL Transmission Unit (HTU)

Exchange
Customer
91
Features of HDSL

• Existing E1 needed line conditioning
• No need of repeaters for HDSL
• Greater Reach
• Data Rates

92
HDSL Line Coding Modulation

• 2B1Q (4-PAM) 2 binary 1 quaternary
• Simple Modulation scheme
• An amplitude and phase modulation scheme
• Reduces the frequency spectrum by half
• CAP

93
HDSL Applications

• Designed for Business users
• Symmetric nature - same upstream and downstream
  data rates
• Examples of Applications
• Video Conferencing Distance Learning.
• LAN/LAN interconnect
• Web hosting

94
Other forms of HDSL

• Symmetric Digital Subscriber Line (SDSL)
• Symmetric
• One copper pair
• Range of speeds

• Uses 2B1Q coding
• Phased out
• Proprietary

95
Other forms of HDSL cont

• Single-pair high-speed DSL (SHDSL)
• Known as G.shdsl with ITUT and HDSL2 with ANSI
• Single pair of wires
• Distance ranges between 1.8 km to 6.5 km
• Data Rates between 192 kbit/s to 2312 kbit/s (and
  growing)
• Why SHDSL?
• Does not coexist with POTS

96
VDSL

• Very fast DSL resembling ADSL
• Asymmetric and Symmetric
• Faster Data Rates
• Short distance from exchange
• Provides for POTS and DSL
• Uses Fibre in the loop network topology
• ITU-T Recommendation G.993.1

97
VDSL Equipment

• Transmission Line
• VDSL Modem

• Service Module
• Splitter

98
VDSL Limitations Line Coding

• Limitations
• Distance
• Crosstalk Interference

• Line Coding
• The same as ADSL
• Two consortiums
• Coalition - QAM/CAP
• Alliance - DMT

99
VDSL Data Rates Distance
100
VDSL Frequency Graph
DS Downstream US Upstream Opt Optional
(either upstream or downstream)
Frequency (MHz)
101
VDSL Applications

• Services that rely on fast data rates will
  benefit from VDSL
• Fast Internet browsing
• Video on demand
• Remote Learning applications
• Telehealth
• High Quality Teleconferencing
• Audio downloads
• The only DSL service capable of the convergence
  of telephony, data and video

102
Current and Emerging DSL Technologies

• IDSL (ISDN DSL)
• Uses the data network and bypasses exchange
  switch
• Data rates are the same as ISDN 144 kbit/s at a
  distance up to 5.5 km
• Benefits of IDSL
• Always on
• Flat rate rather than a per call rate
• VoDSL (Voice over DSL)
• Supports Voice and Data
• Supports multiple voice calls over single DSL
  circuit
• Dynamic Bandwidth
• All transmissions are digital

103
Comparison of xDSL Technologies
104
Comparison of xDSL Technologies
105

• Fiber To The Home (FTTH)

106
What is FTTH?
Copper
Fiber
//
24 kbps - 1.5 Mbps
Old networks, optimized for voice
Note network may be aerial or underground
107
What is FTTH?

• An OAN in which the ONU is on or within the
  customers premise. Although the first installed
  capacity of a FTTH network varies, the upgrade
  capacity of a FTTH network exceeds all other
  transmission media.
• OAN Optical Access Network
• ONU Optical Network Unit
• OLT Optical Line Termination

OAN
CO/HE
//
ONU
OLT
Source www.ftthcouncil.org
108
FTTH Components
Philosophy - Retail - Wholesale
Architecture (Electronics) - PON? - Active
node? - Hybrid?
Transport - ATM? - Ethernet?
Optical fiber and lasers
CO/HE
//
Technical considerations
109
Why FTTH?

• Enormous information carrying capacity
• Easily upgradeable
• Ease of installation
• Allows fully symmetric services
• Reduced operations and maintenance costs
• Benefits of optical fiber
• Very long distances
• Strong, flexible, and reliable
• Allows small diameter and light weight cables
• Secure
• Immune to electromagnetic interference (EMI)

110
Why FTTH? - more capacity
Typical system capability for 100 m link
111
Why FTTH? - longer distances
Typical distance for 1 Gbps system capability
112
Why FTTH? - fiber versus copper

• A single copper pair is capableof carrying 6
  phone calls
• A single fiber pair is capable ofcarrying over
  2.5 millionsimultaneous phone calls(64 channels
  at 2.5 Gb/s)
• A fiber optic cable with the sameinformation
  carrying capacity (bandwidth) as a comparable
  copper cable is less than 1 of both the size and
  weight

113
Why FTTH? - fiber versus copper
//

• Glass
• Uses light
• Transparent
• Dielectric material-nonconductive
• EMI immune
• Low thermal expansion
• Brittle, rigid material
• Chemically stable

• Copper
• Uses electricity
• Opaque
• Electrically conductive material
• Susceptible to EMI
• High thermal expansion
• Ductile material
• Subject to corrosion and galvanic reactions

114
How do optical fibers work?

• Core
• Carries the light signals
• Silica and a dopant
• Cladding
• Keeps the light in the core
• Pure Silica
• Coating
• Protects the glass
• Acrylate (plastic)

115
How do optical fibers work?

• Optical fibers work on the principle of total
  internal reflection
• Light waves (modes) are reflected and guided
  down the length of an optical fiber

CORE
CLADDING
116
Types of lasers used

• There are two laser technologies that are used
  for nearly all single mode communications
  applications
• Fabry-Perot (F-P) lasers
• Lower in cost, lower in power
• Poorer wavelength stability
• Distributed Feedback (DFB) lasers
• Higher cost, higher power
• Excellent wavelength stability
• Excellent temperature stability
• Internally modulated
• Good for moderate powers and distances
• Externally modulated
• Ultimate today for quality in broadcast
  applications
• Vertical Cavity Surface Emitting Lasers (VCSELs)
• Coming technology, promises lowest costs

117
Types of lasers used

• Wavelengths used for Single Mode Fiber (long
  distances) communications
• 1310 nm
• Usually lowest cost lasers
• Used for shorter broadcast runs and short to
  moderate data runs
• 1550 nm
• Can be amplified with relatively low-cost erbium
  doped fiber amplifiers (EDFAs)
• Lasers are fabricated on a number of different
  wavelengths (about 1535 1600 nm) for wave
  division multiplexing (WDM) applications
• Slightly lower fiber loss at 1550 nm
• 1490 nm
• Increasingly popular for downstream data in 3l
  systems.
• Cannot be amplified as easily
• Somewhat higher device cost

118
Single and Dual Fiber Systems

• Single Fiber
• Downstream broadcast on 1550 nm
• Upstream data on 1310 nm
• Downstream data on either 1310 or 1490 nm
  depending on system
• Advantages
• Less fiber deployed
• Fewer optical passives (taps or splitters)
• Fewer labor-intensive connections

Downstream data can be carried at 1550 nm if
not used for broadcast
119
Single and Dual Fiber Systems

• Dual Fiber
• Various plans, usually one fiber will be used for
  downstream and one for upstream, or one will be
  used for broadcast and one for data. Sometimes
  one will be used for specialized services, such
  as returning RF-modulated data from set top
  terminals
• Advantages
• Simplifies terminal passive components
• Somewhat lower signal loss

120
Architectures

• Passive Optical Networks (PONs)
• Shares fiber optic strands for a portion of the
  networks distribution
• Uses optical splitters to separate and aggregate
  the signal
• Power required only at the ends
• Active Node
• Subscribers have a dedicated fiber optic strand
• Many use active (powered) nodes to manage signal
  distribution
• Hybrid PONs
• Literal combination of an Active and a PON
  architecture

Skip Details
121
Architectures PON (A-. E- or G-)
Usually 10-20 km
//
OLT
//
ONU
//
//
//
Optical splitter 1x16 (1x2, 1x8) 1x32 (1x4, 1x8)
//
122
Architectures PON (2) (A-. E- or G-)
1550 nm broadcast (if used)
//
OLT
1490 nm data
//
ONU
//
//
1310 nm data
//
//
Data may be transmitted at 1550 nm if not used
for video
123
Architectures Active Node
Up to 70 km
Up to 10 km
//
OLT
//
ONU
//
//
Processing (powered)
//
124
Architectures Active Node (2)
//
1550 nm broadcast (if used)
OLT
//
ONU
//
//
Data, 1310 or 1550 nm (depending on distance) on
separate fibers
//
125
Architectures Hybrid PON
Up to 70 km
Up to 10 km
//
//
OLT
Optical splitter
//
ONU
//
Processing (powered)
//
//
//
Optical splitter
126
Architectures Hybrid PON (2)
Single fiber, 1550 broadcast, 1310 bidirectional
data
//
//
OLT
1550 nm broadcast
//
ONU
//
//
Data, 1310 or 1550 nm (depending on distance) on
separate fibers
//
//
127
Technical considerations

• Data
• How much per home?
• How well can you share the channel?
• Security how do you protect the subscribers
  data?
• What kind of QoS parameters do you specify?
• Compatible business services?
• SLAs
• T1
• Support for voice?
• Support for video?
• Broadcast
• IPTV

128
Technical considerations

• Data
• How much per home?
• How well can you share the channel?
• Security how do you protect the subscribers
  data?
• What kind of QoS parameters do you specify?

129
Technical considerations - Speed

• Data requirements
• Competition ADSL, cable modem 0.5 to 1.5 Mb/s
  shared, asymmetrical
• FTTH 10 to 30 Mb/s non-shared or several 100
  Mb/s shared, symmetrical
• SDTV video takes 2-4 Mb/s today at IP level
• HDTV takes maybe 5 times STDV requirement
• Pictures can run 1 MB compressed
• 5.1 channel streaming audio would run 380 kb/s

130
Technical considerations - Speed
131
Technical considerations Speed
Estimated minimum time to acquire
Braveheart
August 17, 2001
MGM, Paramount Pictures, Sony
Pictures, Warner Brothers, and
Technology
Minutes
Hours
Days
Universal Studios unveiled plans
for a joint venture that would
Modem 56
allow computer users to
2
kb/s
download rental copies of feature
films over the Internet.
ISDN 128
20
kb/s
December 9, 2002
12
Hollywood's Latest Flop
Fortune Magazine
DSL 1 Mb/s
2.5
The files are huge. At 952
Megabytes, Braveheart took just
Cable 2.5
1
less than five hours to download
Mb/s
using our DSL Line at home in
45
the same time we could have
made 20 round trips to our
FTTH
0.4
neighborhood Blockbuster

132
Technical considerations

• Security
• Data is shared in the downstream direction in
  most systems
• Your Gateway filters out all packets not intended
  for you
• But there is fear that someone will snoop on your
  data
• FSAN has a low-complexity, low-security
  encryption scheme
• 802.3ah has formed a committee to study security
• Manufacturers have taken their own tacks on
  security, from none to robust

133
Data Flow and Security - Downstream
Time division multiplex (TDM) each subscribers
data gets its turn.
//
//
Tom
Dick
//
//
//
Harry
Box on side of home separates out only the data
bound for that subscriber. But the fear is that
someone will fool his box into giving data
intended for another subscriber. Solution is to
encrypt the data.
134
Data Flow and Security - Upstream
Time division multiple access (TDMA) similar to
downstream, with gap for laser start/stop
//
//
Tom
Dick
//
//
//
Harry
Due to the physics of the network, Harrys data
flows upstream but does not come to Toms box, so
Tom cannot see Harrys data
135
Data Flow and QoS
If Dick has paid for more bandwidth, he gets more
//
//
Tom
Dick
//
//
//
Harry
If Toms packets need higher priority (e.g.,
telephone), they go first
136
Telephony Considerations
Depending on whether the FTTH system is based on
ATM or Ethernet, the basis of the phone
technology is either conventional switched
circuit or the newer VoIP
137
Conventional Switched-circuit Telephone
138
Example VoIP System
139
Video
Video is a popular service, which is a good basis
for any new entrant FTTH provider. There is one
way to provide video on cable and satellite
(broadcast) and one way to provide video on DSL
(IPTV). There are two ways to provide video on
FTTH (broadcast and IPTV). The market place can
sort out the use of each, to the benefit of the
subscriber. We will describe the differences.
140
Technical considerations - Video

• Can send video several different ways on FTTH
• Broadcast (cable TV standards)
• Analog
• Digital
• Cable TV good engineering practice is 47-48 dB
  C/N
• FTTH can achieve 48-51 dB C/N
• Benefit from high volume and plethora of
  applications of cable boxes
• RF return support for STTs
• IPTV TV transmitted over Internet Protocol
• Feasible, and some people are doing it in place
  of broadcast
• Bandwidth hog, but statistics can work for you
• Interesting hybrid model awaits hybrid STTs, but
  can give the best of both worlds

Skip Details
141
Ways of transmitting video
142
Ways of transmitting video wave division muxing
143
Ways of transmitting video broadcast headend
144
Ways of transmitting video broadcast subscriber
145
Ways of transmitting video IPTV headend
146
Ways of transmitting video IPTV subscriber
147
Ways of transmitting video IPTV unicast (VOD)
148
Ways of transmitting video IPTV unicast (VOD)
149
Ways of transmitting video IPTV multicast
150
Ways of transmitting video IPTV multicast
151

• END