Developing Cable Telephony Solutions

1. Developing Cable Telephony Solutions Ed Morgan , Executive Director, R&D Texas Instruments VoIP Group emorgan@ti.com

2. Agenda • Packetcable Network Architecture Review • Market Developments • PacketCable • Recent issues update • Media Terminal Adapters Hardware and Software

3. PSTN IPNetwork Voice over Cable Architecture PC Embedded MTA Cable Modem TV MediaGateway Cable MSOs Comcast, Cox, TWC etc. Cable HeadEquipment WLAN Phone Cable Modem IP Phone TA PC 3G Wireless TV Independent TSP AT&T, Qwest, Verizon, Vonage etc.

4. PacketCable Network Reference Diagram Record KeepingServer Billing system OSS/NMS CMTS HFC accessnetwork(DOCSIS) PacketCableIP network(single zone) Managed IPBackbone Cable Modem MTA CallManagementServer Embedded MTAClient SignalingGateway MediaGateway (Call Agent) MGCP PSTN

5. Market Developments Cable telephony services from Cable MSOs and Independent Telephony Service Providers are in widespread deployments • Cable MSO Advantages • Bundled product – common billing • Better control over QOS through Packetcable • Security implementation through Packetcable • Independent Service Provider Advantages • Mobility – take your telephone number with you when you go on vacation • WLAN phones integration with cellular will increase mobility • Low network infrastructure investment provides cost advantages

6. PacketCable Voice – Recent Topics • Fax calls • Modem calls • Royalty free codecs

7. Fax and Modem Calls over Cable • Problem • Packet loss – without any error correction techniques, call success rates drop drastically with 1% packet loss. • Clock offset at end-points will cause jitter buffer re-centering, hence periodic modem retrains and potentially dropped calls • Solution • T.38 fax relay for fax calls • RFC 2733 - Forward Error Correction (FEC) and RFC 2198 – Redundancy for modem calls

8. PSTN IPNetwork Fax Relay • Demodulates incoming T.30 fax signals at the transmitting gateway • Translates T.30 fax signals into T.38 Internet Fax Protocol (IFP) packets • Exchanges IFP packets between transmitting and receiving T.38 gateways • Translates T.38 IFP packets back into T.30 signals at the receiving gateway • Modulates T.30 signals and transferring them to the receiving fax machine and vice versa Fax Cable Modem with T.38 T.38 enabled MediaGateway Cable HeadEquipment PC TV

9. Key Elements of Fax Relay • Fax relay provides: • Delay Compensation • Must compensate for the effects of the additional delay added by packet networks • Packet Loss Compensation • Must compensate for the effects of packet loss and packets received out of order • Interoperability with a wide range of fax machines • Must be compatible with mandatory and optional T.30 features • Must be hardened through use in a variety of networks/environments • Other value-added fax features: • Ability to limit the high-speed data rate negotiated by the fax machines to less than available network bandwidth

10. Call Success Rate vs. Network Packet Loss 100 80 60 Call Success Rate (%) 40 PCM (No Fax Relay) Telogy's R3 Software Telogy’s R8 Software 20 1 2 3 4 5 6 7 8 9 10 Random Packet Loss (%) Advantage of Fax Relay for Packet Loss • Error hiding techniques improve fax call success rate in the presence of packet loss

11. Modem Relay and VBD • V.150.1 is an ITU standard defining an approach to supporting modem traffic over IP networks • V.150.1 is a similar approach to fax relay but it has a very high memory and MIPs cost that will raise the cost of the cable telephony system • An alternative approach is to use the VBD standard (V.150.2) where modem signals passed end-to-end through the VoIP gateway using G.711 and add forward error correction and redundancy using RFC 2733 and RFC 2198 • The advantage of this approach is the relative simplicity and low cost of implementation • The disadvantage is the added bandwidth required if redundancy is used

12. Royalty Free Codecs • Objective is to introduce “royalty free” codecs into Packetcable spec to lower the BOM cost of cable modem and avoid royalty associated with ITU approved codecs (G.729E and G.728 are optional today) • Two candidate have been identified – iLBC from Global IP sound and BV16 from Broadcom • Current status is that codecs have incorporated into the Packetcable Spec 1.1 • There are number of interop and IPR review gates to get through before acceptance • Long term viability of these codecs is questionable without standardization because of need to interop with standard codecs in other VoIP and wireless systems • Implementation of Wireless codecs like GSM-AMR and WB-AMR are needed because of interop with wireless systems.

13. HFC accessnetwork(DOCSIS) PacketCableIP network(single zone) Managed IPBackbone Cable Modem MTA MTA Embedded MTA SignalingGateway MediaGateway Standalone MTA PSTN Cable Modem Media Terminal Adapters Standalone vs Embedded

14. SDRAM FLASH Ether XVR SRAM RAM ROM CPU DOCSIS DOCSIS Tuner PHY MAC Embedded Media Terminal Adapter (EMTA) Cable Modem HPNA 802.11 Eth MAC SLIC & CODEC DSP

15. SDRAM FLASH SRAM RAM ROM RISC CPU RISC CPU DOCSIS DOCSIS Tuner PHY MAC Standalone Media Terminal Adapter (SMTA) Cable Modem DSP 802.11 HPNA Ether Xcvr Ether Xcvr Ether Mac Ether Mac SLIC & CODEC USB

16. Packet Cable mgmt. Voice Signaling DOCSIS mgmt. OS IP Stack Bridge Security DOCSIS L2 mgmt. Voice Processing DOCSIS 1.1 Downstream DOCSIS 1.1 Upstream Ethernet BSP OS HAL DSP CPU Peripherals Cable Voice-EnabledCableModem Software Architecture

17. Summary • The evolution of today’s communication networks is driving changes in VoCable applications • Cable telephony is adapting to provide integration with new communication technologies and services such as WiFi and 3G Wireless • New developments in Packetcable are needed to address holes in the service offering like fax and modem support