Developing Cable Telephony Solutions

Michael MetzgerExecutive Director, MarketingMindspeed Technologies, Inc.

Agenda

• Introduction• Voice over Cable Architectures• Cable Standardization Bodies• High Density Cable Gateway SoC Solutions• EMTA SoC Solutions• What’s Next in Voice over Cable?

Introduction• VoIP over Cable is experiencing strong

growth within North America • Forecast of more than 17 M Voice over Cable

subscribers in 2008• VoIP over Cable completes MSOs offering for

triple-play voice, video, and data services• Fundamental change in architectures

moving to Packet-based networks from analog Voice over Cable

Voice over Cable – Current Architecture

PSTN

IP Network

Headend Class 5Switch

NetworkInterface Terminal

Cable Modem

• Analog voice traffic placed on cable medium, and connected to PSTN using traditional Class-5 switch

Next Generation – VoIP over Cable

PSTN

IP Network

Media GW,Signaling GW

CMTS

EMTA

Voice Traffic

Data/Voice Traffic Call Mgmt

Server

• True VoIP over Cable, packetized in converged MTA solutions

• Migration to all IP networks

SBC

IP Network

WiFi

PacketCable

• Specification forum focused around detailing the architecture for next-generation IP Cable networks

• For Voice, PacketCable details:o QoSo Securityo PSTN & IP Interconnecto Lawful Intercepto Reliability

IPCablecom Standardization Process

ITU-T

SCTETCC

(Japan)ETSI

CableLabs(projects)

ECCA(requirements)

Vendor Vendor Vendor

Global Standards(J.160 – J.174)

Regional Standards

Contributors

PacketCable – Timeline

• Rel 1.0o Architectural framework for Packet-based Cable

networks (1999)

• Rel. 1.5o Added new voice codecs, fax relay (2005)

• Future Releaseso IMS architecture & mobilityo Call control moving to SIPo New voice and video codecs

PacketCable – QoS

• Quality of Service in PacketCable networks must at a minimum be equal to that of the PSTNo Fundamental requirement to drive adoption

• Major Factors affecting QoS for voice:o Voice Compression Technologyo Packet Losso Packet Latency/Delayo Echo Cancellation

• To ensure high QoS, SoCs must address the above

Typical High-Density Gateway Solution

Control and Signaling

Host Operating System

Media Stream Processing

InternalMemory

N x DSP

DSP Resource Manager

Voice Channels

Signaling Stacks

Control Applications

TDM

Ethernet

Media Stream Processing sub-system offloads host CPU

Ethernet

SoC Solutions for High Density Gateways

PSTN IP

SoC

SoC SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

Ethernet Switch

SoC

TSI

Ethernet PHY

OC-3

VoIP to TDM (with/without encryption)

Media Forking for CALEA (with/without encryption)

Transcoding (IP-IP)(with/without encryption)

SoC Architectures for High Density Gateways

VoiceDSP

TSI

Packet Processor

SoCVoiceDSP

VoiceDSP

VoiceDSP

Security

Ethernet TDM

Memory

DSP Functions: Codecs

• Limited uplink speed demands complex voice codecs

• Echo Cancellation G.168-2002/4• Required G.711, recommended G.729e,

G.728 (Rel. 1.0)• Added required iLBC, BV-16 (Rel. 1.5)• Future release

o Wide-Band Codecso Wireless Codecs

Example of Wireline/Wireless Codec: SMV

• Selectable Mode Voice Codec (SMV): Standardized for CDMA2000• G.711 Equivalent Voice Quality• Music Detection• Efficient Rate Determination Algorithm: Average Bitrate ~ 4kbit/s• 4 coding rates: (full-rate:8.5kb/s, half-rate: 4.0kb/s, quarter-rate:

2.0kb/s, eight-rate: 0.8kb/s)

Output bit stream

Encode with 4.0kb/s bit-rate

Encode with 2.0kb/s bit-rate

Encode with 0.8kb/s bit-rate

M U X

Input speech

Encode with 8.5kb/s bit-rate

VAD

Additional parameters extraction

Logic of rate determination

Mode requirement

RDA module

DSP Functions: Intelligent Transcoding

• Increasing demand for Voice transcoding with migration to an all IP network

• Dynamic prediction algorithms prevent the degradation of voice quality inherent in typical G.711 transcoding schemes

• Roundtrip delay critical for voice quality over an IP network is significantly minimized

• No echo cancellation required

Fax & Modems Transport

Required Packet & DSP functions:• Transmit V.90 and 14.4 kbit/s FAX (over

G.711)• T.38 Fax Relay

o 40 ms frame sizeso Packet redundancy

• Synchronization of end-points: less than 0.25 frame slips per minute

Security Processing

• PSTN security is based around the assumption that there is a direct dedicated link between the user and the central officeo In PacketCable networks, shared medium is used

• As such, cryptographic methods are used to provide security in PacketCable for call privacy

• Optional implementationo 128-bit AES encryptiono MMH/SHA-1 for message authentication

Packet Cable Voice Payload Encryption

IP UDP Voice payload Authentication

Authenticated Portion

(MMH)

Encrypted Portion (AES)

RTP

5 x 9s Reliability with N:1 Redundancy

Active1

Active 2 voiceActive 3

74mm

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SoCMiro

SoCMiro

SoCMiro

ADM6326

IDT72V71660

FPGA

Flow

Classifier

74mm

SoC

SoCMiro

SoC

SoCMiro

SoC

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SoC

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SoC

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SoCMiro

SoCMiro

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SoCMiro

SoCMiro

SoCMiro

SoCMiro

SoCMiro

SoCMiro

SoCMiro

ADM6326

IDT72V71660

FPGA

Flow

Classifier

74mm

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

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SoC

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SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

ADM6326

IDT72V71660

FPGA

Flow

Classifier

SoC

SoC

SoC

SoC

SoC

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SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

SoC

Ethernet Switch

StandbySoC

Low to Medium Density MTA’s

SHM Voice

DSP core

TSI

MMU

Control & SignalingProcessor

DualEMAC

SoC

CablePHY

Memory

Tele

ph

on

y I

nte

rfaces

EXPANSIONBUS

CSP

1 to N Telephones

Ethernet

Voice & Data Routing

Embedded MTA

Security

USB2.0

Printer or Peripheral

PCIMSPWi-Fi

CSP & MSP ModelN

on

Re

al-

tim

eR

ea

l-ti

me

TDM

Cable Modem

CSPControl & Signaling Processor

MSPMedia Stream

Processor

Virtual EthernetDriver

Single UnifiedMemory

DDRSDRAM

• Deterministic Voice Quality & Data Routing/VPN Performance

o MSP/CSP partitioning for real-time & non real-time processes

• Corner case interoperability & standards compliance

o CODECs & common functions run on MSP

• New/3rd Party Applications does not affect MSP Processing

o CSP hosts applications independent of media stream

o E.g Linux or VxWorks

Telephony InterfacesTelephony Interfaces

Ethernet

Open Source Applications for a CSP

Project Application HomeLinux Kernel 2.6 UNIX OS with integrated

IPSec http://www.kernel.org/

Apache Web Server http://www.apache.org/

Busybox Common UNIX utilities http://www.busybox.net/

Asterisk PBX, IVR, voicemail http://www.asterisk.org/index.php?menu=features

OpenH323 H.323 protocol http://www.openh323.org/

OpenSIP SIP user agent, proxy http://www.gnu.org/software/osip/osip.html

MGCP MGCP implementation http://www.vovida.org

Festival Lite Text-to-Speech engine http://www.speech.cs.cmu.edu/flite/

PPTP Client VPN software http://pptpclient.sourceforge.net/

iptables firewalling subsystem http://www.netfilter.org/

GNU Zebra Routing Protocol Manager http://www.zebra.org

gcc C/C++ Cross compiler http://gcc.gnu.org/

gdb Debugger http://sources.redhat.com/gdb/

Ethereal Network Sniffer (with MND plugin)

http://www.ethereal.com/

KDevelop Flexible IDE http://www.kdevelop.org/

Development Tools Telephony Core Networking

What’s Next in Voice over Cable?

• Mobility o Support cellular handset/WLANo Wireless/Wireline Transcoding in Cable GW

• Call control mechanismso TGCP SIP

• Migration to IP V6• Integration of Session Border Controllers functions

into Cable GW• Adoption of IMS Architecture• Instant messaging (IM)