slide1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Cable Modem : Technology Venkata C. Majeti 4343 Commerce Court Lisle, IL 60532 Tel: (630) 281 - 3152 Email: venkata@cada PowerPoint Presentation
Download Presentation
Cable Modem : Technology Venkata C. Majeti 4343 Commerce Court Lisle, IL 60532 Tel: (630) 281 - 3152 Email: venkata@cada

Loading in 2 Seconds...

play fullscreen
1 / 18

Cable Modem : Technology Venkata C. Majeti 4343 Commerce Court Lisle, IL 60532 Tel: (630) 281 - 3152 Email: venkata@cada - PowerPoint PPT Presentation


  • 379 Views
  • Uploaded on

Cable Modem : Technology Venkata C. Majeti 4343 Commerce Court Lisle, IL 60532 Tel: (630) 281 - 3152 Email: venkata@cadant.com. Outline. Cable television network architecture Migration of cable networks to hybrid fiber-coax networks Use of cable RF spectrum

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Cable Modem : Technology Venkata C. Majeti 4343 Commerce Court Lisle, IL 60532 Tel: (630) 281 - 3152 Email: venkata@cada' - liam


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Cable Modem : Technology

Venkata C. Majeti

4343 Commerce Court

Lisle, IL 60532

Tel: (630) 281 - 3152

Email: venkata@cadant.com

slide2

Outline

  • Cable television network architecture
  • Migration of cable networks to hybrid fiber-coax networks
  • Use of cable RF spectrum
  • Recent changes to the use of RF spectrum
  • Developments in cable modem technology
  • Cable modem details:
    • Physical (PHY) layer specification and design
    • Media Access Control (MAC) layer specification and design
    • Data encapsulation
    • Signaling & Control
  • Data Over Cable Services Interface Specification (DOCSIS) standard
  • Other related standards: PacketCable, OpenCable, & EuroDOCSIS
slide3

Cable Television Network Architecture

Cisco 2500

Cisco 2500

Summary - headend at a glance

Ethernet switch

Fiber

Transmitter

CMTS

Passive

combiner

channel

lineup

video

reception

battery

backup

digital video storage

slide4

Migration of CATV Networks to HFC Networks

Community Antenna Television (CATV) network evolution :

( a ) “Tree and Branch” Architecture

( b ) Capacity increase via “fiber trunks”

( c ) Evolution to “Fiber Serving Areas”

slide5

Migration of CATV Networks to HFC Networks

main trunk

main trunk

Headend/

Hub

(a) traditional tree-and-branch architecture

slide6

Migration of CATV Networks to HFC Networks

Headend/

Hub

main trunk

Node

Headend/

Hub

(b) traditional tree-and-branch with fiber trunks

slide7

Migration of CATV Networks to HFC Networks

main trunk

Node

Node

Headend/

Hub

(c) tree-and-branch with fiber-serving-areas

slide9

Use of Cable RF Spectrum

Headend

Downstream

Upstream

signaling

. . .

550 MHz - 750 and up MHz

50 MHz - 550 MHz

5-40

MHz

1 NTSC Video Channel per 6 MHz RF Carrier

Bandwidth Use in CATV Networks

Cable distribution network has limited (shared) upstream capability in 5- 40 MHz range. Most cable systems use

50 - 550 MHz range for downstream broadcast video signal.

slide10

Recent Changes to the Use of RF Spectrum

. . . .

Encoding schemes assume multiplexing

of many DS0/MPEG channels to form one

6 MHz NTSC channel for distribution over

existing facilities.

1 NTSC Video Channel per 6 MHz RF Carrier

Increasing the Cable Distribution Capacity

Downstream

. . .

Upstream

50 MHz - 550 MHz

550 MHz -

5-40

MHz

slide11

Developments in Cable Modem Technology

Products

Zenith, LANcity, Hybrid Networks

Proposals

PHY Layer

Scientific Atlanta

Amati

Alcatel

CORTEC

Stanford Telecom

Zenith

General Instrument

AT&T / Lucent

Microunity

IBM

Aware

MAC Layer

TDMA

F-TDMA

XDQRAP

M3

ADAPt

UPSTREAMS

CDMA/S-CDMA

SEMAP

MLAP

FPP

Key Issues

Modulation Techniques

Upstream Noise

Data Link Layer Format

Loop length – propagation delay

Privacy over shared media

-----

Ranging, Registration

Upstream Frame Format

Timing Source & Uncertainties

Superframe

Frame

Slot

slide12

Cable

Modem

O/E

Node

Fiber

Security

Authentication

Local Servers

Cable Data Network architecture

Router

Interface

Alternative

telephone

return interface

slide13

Data Over Cable Service Interface Specifications (DOCSIS)

Cable Modem Termination System - Network Side Interface

Cable Modem - Customer Premise Equipment Interface

Operation Support System Interface

Cable Modem Telephony Return Interface

Radio Frequency Interface

Baseline Privacy Interface

Security System Interface

Removable Security Module Interface

CMTS-NSIOSSIRFI

CMCICMTRIBPI

SSI

RSMI

slide14

RFI

Downstream

  • 6 MHz spectrum
  • 64/256 QAM
  • Reed-Solomon block code and Trellis Code
  • Variable depth interleaving to support latency
  • Contiguous serial bit-stream w/ no implied framing

Upstream

  • Frequency agile
  • QPSK/16 QAM
  • Multiple symbol rates, data rates
  • CM programmable by the CMTS
  • Supports fixed-frame and variable length PDUs
  • Programmable Reed-Solomon block coding
  • Time Division Multiple Access (TDMA)
slide15

MAC (media access control) Layer

  • CMTS-controlled mix of contention and reservation
  • Stream of mini-slots in upstream
  • Fixed and variable-length packets
  • Extensions to support ATM PDUs
  • Support for multiple data rates
  • Support for multiple grades of service
slide16

Routing

DATA FORWARDING THROUGH THE CM AND CMTS

slide18

Resources

Albert Azzam, “High-Speed Cable Modems,” McGraw-Hill Series on

Computer Communications, Published in 1997.

Venkata Majeti (Executive Editor), “Cable Modems: Current Technologies

And Applications,” Published by the International Engineering Consortium

And the IEEE Press, 1999.

CableLabs: resource for DOCSIS, PacketCable and OpenCable initiatives.

URL: www.cablelabs.com

Market Information: www.cabledatcomnews.com

Other market research information from various investment banks.