* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download voip - KEMT FEI TUKE
Survey
Document related concepts
Zero-configuration networking wikipedia , lookup
Multiprotocol Label Switching wikipedia , lookup
Distributed firewall wikipedia , lookup
Computer network wikipedia , lookup
Serial digital interface wikipedia , lookup
Piggybacking (Internet access) wikipedia , lookup
Network tap wikipedia , lookup
Airborne Networking wikipedia , lookup
Cracking of wireless networks wikipedia , lookup
Deep packet inspection wikipedia , lookup
Wake-on-LAN wikipedia , lookup
Asynchronous Transfer Mode wikipedia , lookup
Transcript
1 VoIP (Voice Over IP) 2 VoIP Network Gateway functionality is required to adapt the PSTN transmission to IP (the Internet Protocol) Intranet/Internet G/W Analog Local Loop Packet Switched Logical Connections G/W Analog Local Loop 3 Voice Gateway A gateway provides: Signaling - dial tone, call set-up etc. (H.323, MGCP, SS7) Conversion to IP, (often Ethernet, possibly ATM) Compression (G.711, G.723.1 etc.) Echo Cancellation Quality of Service (QOS) Packet Network 4 Interfaces Gateway Product phone fax modem PBX Physical Interfaces Tone Interfaces Signaling Interfaces Voice/Fax Processing Analog Tone Generation CAS ulaw alaw linear pulse dialing 2W/4W loop start ground start gain control DTMF Call Progress Tone FXS FXO E&M Transparent Echo Cancellation Digital Key Systems Central Office T1/E1 T3 OC1/OC3 Voice Coding Tone Detection DTMF V.21 Call Progress MF (R1, R2) Modem Tone DTMF Tone Relay VAD CCS Q.931 QSIG Transparent Voice Playout Fax Modem V.21 V.27ter V.29 V.17 V.33 N e t w o r k I n t e r f a c e Packet Network 5 Voice/Fax Standards Voice over IP H.323 SS7 MGCP SIP TCP/IP Tone detection Echo cancellation (G.165, G.168) Voice codecs V.x modems Voice over Frame Relay Voice over ATM AAL2 Voice over Cable FRF.11 DOCSIS 1.1 MGCP Fax over Packet T.37, T.38 6 Inter Operability Packet Network H.323 Gateway Gateway Product T e l e p h o n y I n t e r f a c e Network Management Interface Functions Address Translation and Parsing Signaling Translation CAS H.323/FRF.11/ATM CCS H.323/FRF.11/ATM Fax Relay/ Advanced Local Processing H.323 Network Protocol Interface FRF.11 Network Protocol Interface ATM IP Networks P r o t o c o l S t a c k s PC w/ H.323 Node Frame Relay Gateway Frame Relay Networks ATM Networks ATM Gateway Standard In Work Proprietary Today 7 ITU-T Speech Coding Standards 70 64 kbps 60 Bandwidth 50 G.711 40 G.726 32 kbps G.728 G.729AB 30 20 G.723 16 kbps 8 kbps 10 5.3 kbps 0 1 Voice CODEC 8 Subjective Voice Coder Quality 5 G.711 PCM 4 G.726 ADPCM Mean3 Opinion Score (MOS2 ) G.728 LD-CELP G.729 G.729AB GSM 1 G.723.1A 0 5.3 6.3 8 16 32 64 Kpbs 9 VoDSL (VoIP &VoATM) IP IP PPP PPP VoIP AAL2 AAL5 ATM AAL5 Lifeline POTS AAL2 VoATM ATM ADSL INTERLEAVED PATH PLVT VoIP ADSL FAST PATH DSL Client Access Network ISP or Core PLVT Lifeline POTS 10 TI’s Golden Port Integrated software with simultaneous support for: Voice - Fax - V.90 Modem - Signaling 11 Network Requirements Scalability - products typically range from 24/30 ports (T1/E1) to thousands of ports Small Footprint - rack space in central offices and ISP POPs is expensive Power Consumption - critical for both cost and heat Cost - cannot afford idle resources Simultaneous voice relay, fax relay, V.90 modem termination Non-Blocking Manageable - accounting and operations 12 Network Efficient Utilization Network Type Bandwidth Utilization Grade of Service Telogy Software Provides Choice of low bit rate codecs Configurable voice packet sizes (10 ms to 80 ms) Efficient Voice Activity Detector (VAD) Fax demodulation/remodulation Ability to restrict max fax transmission rate, e.g., 2400, 4800, 9600 bps Sub-Channel Multiplexing - FRF.11 13 Universal Access PSTN Replacement requires support for Voice, Fax and V.90 Modem Capital Cost Idle Equipment Recurring Cost Discrete Trunks Packet Network 14 Channel Density Multi-Instance - ability of software to support multiple modems in same DSP Old software base hard-coded for single channel operation; difficult to migrate to multi-channel Software designed for multi-channel operation from its inception results in a more robust product Critical decisions on MIPS and memory vs. modem performance tradeoffs Skimping here will result in a poor performing solution 15 Hardware Architecture Multi-processor Maximizes scalability Real time call discrimination Eliminates the requirement for discrete trunks 16 Multi Processor T1/E1 Building Block Digital Signal Processor(s) (DSP) Voice Compression Tone Detection/Generation Echo Cancellation Silence Suppression Fax Modem V.90 Data Modem PSTN Trunks DSP DSP RISC Processor Modem Control Processing CISC or RISC Processor DSP Ethernet (Internet) DSP Telephony Protocols Network Protocols Management Routing Billing 17 Dynamic Call Discrimination Determines on a call by call basis if the calling “device” is a Human, Fax Machine, or a Modem Tone Detection Flag Detection Called number parsing DSP DSP RISC CISC Ethernet (Internet) DSP DSP 18 Echo Cancellation Every 60 miles between the Gateway’s echo canceller and the reflecting hybrid requires 1 ms of echo tail 480 Miles Gateway PBX CO Switch with echo canceller 960 1,920 Miles Miles 60 Miles 1 ms 16 ms 8 ms 32 ms Telogy Software provides selectable tail length from 8 ms to 128 ms, G.165, G.168 compliant 19 Packet Loss Voice/Fax Lost Packets Due to: •Network Congestion/Performance •Network Architecture •Improper Jitter Buffer Size •Software Not Designed for Peak Load Gateway Product Potential Causes of Packet Reordering: •Network Congestion/Performance •Network Architecture Gateway Product Packet Network 5 6 Lost Telogy Voice Software Provides: •Lost packet compensation for all codecs •Lost packet statistics •Peak MIPS design philosophy 2 4 1 Playout Buffer 3 Lost Telogy Fax Software Provides: •Control packet redundancy to correct for lost packets •Advanced local processing to negate the effects of network problems •Very high call completion rates (100% at 5%; 97% at 10) 20 Real-Time Fax Gateway Emulates the Central Office and the remote fax machine (fax modem) Demodulates the fax transmission and extracts the fax data Encapsulates the fax data Transmits the fax data in packets Remodulates the fax data for transmission to the remote fax machine Packet Network 64K bps 64K bps 14.4 Kbps 21 Success Factors for Fax over Packet Networks Packet Compensation Fax Interface Unit to Fax Interface Unit Compatability Delay Compensation Network Call Stability Fax to Fax Interface Unit Compatability Jitter Compensations Analog Signal Quality 22 Fax Latency Originating FTE FIU Destination FTE FIU Network FTE ends transmission and starts T4 timer Delay Duration of T.4 timer (per T.30) Delay Timeout occurs without receiving a reply and FTE starts retransmission of original message. Retransmission from Originating FTE “collides” with reply from Destination FTE 23 Technique To Keep Call Alive Originating FTE FTE ends transmission and starts T4 timer FIU Destination FTE FIU Network Delay Duration of T.4 timer (per T.30) Delay Before timeout at Originating FTE, FIU starts sending “preamble” fill signal in anticipation of receiving message over network. Message arrives over network. FIU remodulates message as it is received. 24 Difference Between a Good Modem and a Great Modem Key Algorithms - where some vendors cut corners Echo Canceller and Equalizer Structure, speed and level of convergence, length Full vs. Reduced Complexity Viterbi decoder Handshaking sequence Works reliably in channel impairment situations Full channel analysis Smart optimization techniques 25 Network Management Challenges Quality Measurement Supervisory Measurement Packet Loss Call Accounting Latency Call Type Jitter Configuration Address Translation Signaling Mode Network Environment Parameters Telogy Software Provides Quality statistics Supervisory statistics Online configuration Complete SNMP MIB for VOP 26 Network Management Diagnostics VOICE MON - Voice Packet Software Monitor PCM trace capability Loop back capability SIG MON - Micro Signaling Trace Monitor Signal level measurements Playout statistics Real-time trace capability Memory dump facility Controllable levels of tracing All significant events including state changes, etc. Customer can route output to Monitoring System FAX MON - Fax Software Monitor Real-time fax trace All significant events Millisecond accuracy on timestamping Compress format interpreted by PC software V. MON - Modem Monitor Real-time trace capability Configuration options Statistics Status 27 Software Scalability What to Look For: Pre-integrated hardware and software scaling from One to Thousands of ports Optimized solutions and cost for all market areas Synchronized feature migration Client Products Access Products Infrastructure Products Telogy Software Client Suite Telogy Software Access Suite Telogy Software Infrastructure Suite Low Density Multi-Function Multi-Channel Multi-Function High Density Broad range of capabilities 28 Intellectual Property It’s a Standards-Based World G.728, G.729, G.723.1, etc. V.90, V.34, etc. Intellectual Property Critical Success Factor for Marketplace Success Now at forefront of Customer focus Key Patents 101 Competitive Issue Affects product costs Liability 29 Traditional Telephony Telephones and Fax Machines connect directly with each other over time division multiplexed circuits Lahore Karachi 30 Central Office Connections are managed by Central Office Switches and Enterprise PBXs Route calls onto digital trunks Provide billing information (Call Detail Records - CDRs) Provide management information (Alarms, Usage etc.) Analog Local Loop Circuit Switched Digital Trunks Analog Local Loop 31 Modems Analog Modem calls are made in the same way as PSTN voice and fax calls Analog Local Loop Circuit Switched Digital Trunks Analog Local Loop 32 Modems and the Internet/Intranet PC Client to WEB Server rather than Peer to Peer Many clients connecting through each POP Digital access trunks required to be operationally economical Remote Access Servers (RAS) An integration of Digital Modems and IP Router POP Packet Network Remote Access Server WEB Server 33 Basics-Analog Voice to PCM An analog voice signal is received The Signal is converted to a Pulse Code Modulation (PCM) digital stream 10110101 11010011 11001001 00100100 00111100 10010011 11100001 00100100 34 Basics-PCM to Frames The PCM stream is fed into the CODEC 10110101 11010011 11001001 00100100 00111100 10010011 11100001 00100100 00111100 11010011 11001001 00100100 00111100 10010011 11100001 00100100 00111100 And Voice frames are created Each Frame is 10 ms long (G.729a) and contains 10 bytes of “speech” 10110101 35 Summary Carrying Voice, Fax and Data over Packet networks provides the most bandwidth efficient method of integrating divergent technologies While the challenges to this integration are substantial, the expanded market addressed by Telogy’s Golden Port make universal port implementations your best choice 36