Fast Robust Ethernet in the First Mile Ethernet end-to-end End Points are Ethernet 90% of LANs are Ethernet Ethernet Used at Desktop Ethernet Used at Servers Ethernet is the most efficient way to carry IP traffic TCP/IP Stack fits naturally on top of Ethernet Internet Protocol (IP) is driving today’s internet Multiservice IP will drive the emerging applications : VoIP, Interactive TV, Presence, Chat, etc. Ethernet is the most cost effective network Optical Ethernet exploding in MAN/WAN Much Cheaper than ATM QOS continues to improve – Traffic Shaping, Policy Manager, Priority Queuing, etc. Copper Based EFM Bridges LAN to MAN Ethernet in the First Mile Interfaces should be 802.3 compliant No SAR - One solution is to encapsulate Ethernet Frames in HDLC Should Leverage Existing Copper Infrastructure The future is fiber (greater bandwidth, lower BER) Fiber deployment is growing, new builds often include fiber at the start BUT… far more consumers are served today by twisted pair than by fiber YANKEE Group estimates 5-7% of market served by fiber Cost of building fiber infrastructure is significant. Copper Loop based EFM can cost effectively provide bandwidth today Ethernet Over ATM Ethernet/TCP/IP Frame S Preamble F Dest Source L/T IP TCP Data FCS D 8 1 6 6 46-1500 4 Octets Segmented Into ATM Cells LLC 0xAA-AA-03 RFC1483 ATM Cell OUI 0x00-00-00 8 7 6 5 4 33 2 1Bit Octet 9 Bytes Octet EtherType 0x08-00 Header Generic Flow Control Virtual Path Identifier 11 Virtual Path Identifier Virtual Ch Identifier 22 Virtual Channel Identifier 33 IP – PDU 5 Bytes Virtual Ch Identifier Payload Cell Type Priority 44 Payload Header Error Check 55 RFC 1483 66 .. .. Frame .. 48 Bytes 48 Bytes Payload Pad (0-47 Octets) .. CPCS-UU Indicator (1 Octet) AAL5 . 8 Bytes CPI (1 Octet) CPCS-PDU .. 8 Bytes Length (2 Octets) 5353 CRC (4 Octets) Trailer Ethernet encapsulated in HDLC Ethernet/TCP/IP Frame S Preamble F Dest Source L/T IP TCP Data FCS D 8 1 6 6 46-1500 4 Octets Encapsulated in HDLC Frame Ex: EtherLoop Burst: 31 1518 Byte Frames per Burst Ethernet Frame Ethernet Frame Ethernet Frame Preamble: 135 Bytes Header, CRC, Flag: 7 Bytes Packet Size EtherLoop ATM (Bytes) 1518 0.7% 11.0% 64 0.7% 30.0% Transport Overhead Modeling the Copper Loop Copper Loop Environment Requires a solution beyond today’s DSL Must adapt to frequency slope Must equalize effects of bridged taps Should continuously adapt to environment Maintain maximum possible throughput Ensure Spectral Compatibility Industry Standard Models Exist ANSI T1E1.4 ETSI FSAN T1.417 Spectrum Management Standard Published T1.417-2001 Spectrum ManagementManagement forfor Loop Transmission Systems Standard published on 2/28/01 Two Methods of Proving Spectral Compatibility Membership in 1 of 9 Spectrum Management Classes Standardized Analysis – Method B Some of the symmetric SM Classes have deployment restrictions Short-Term Stationary (Burst) Conformance Criteria Elastic Networks was a principal author Ensure Spectral Compatibility Contains Standardized Models for Loop environment Loop Insertion Gain Models NEXT and FEXT Models Mixed Crosstalk Models Standardized Curve Fit Loop Model 1 R ( f ) = 1 + 1 4 4 + ⋅ 2 4 4 + ⋅ 2 rOC a C f rOS a S f æ ö b l + l ç f ÷ 0 ∞ è f L ( f ) = m æ ö b 1 + ç f è f m − = + ⋅ c e C ( f ) c ∞ c 0 f + = ⋅ g e G ( f ) g 0 f Copper Environment: Attenuation Slope Insertion Gain for 9kft of 26AWG Wire (CSA 6), with 100 ohm termination -30 -50 -70 -90 -110 CSA 6 Insertion Gain dB -130 -150 -170 -190 0 1000000 2000000 3000000 Freq (Hz) Loop Topologies 600’/ 26 CSA #1 5900’/26 1800’/26 Complex Topologies 700’/ 26 650’/ 26 CSA #4 modeled by 550’/ 26 6250’/26 800’/ 26 cascading 2-port ABCD models of CSA #6 segments with 9000’/26 different gauges 1500’/26 1500’/26 and lengths, and ANSI #13 9000’/26 200 0’/24 500’/ 24 500’/ 24 3-port ABCD models of bridged Indicates Central Office end taps Indicates Remote Device End Some CSA & ANSI Loops Copper Environment: Bridged Tap Echos Frequency Response 3kft 24AWG Line, with 573kft 24AWG Tap 0 -5 -10 -15 dB -20 -25 -30 -35 0 200000 400000 600000 800000 1E+06 1E+06 Freq (Hz) Impluse Response, Insertion Gain 3kft 24AWG Line, with 573kft 24AWG Tap 250000 200000 150000 100000 50000 Response 0 -50000 0 0.00001 0.00002 0.00003 0.00004 Time (Sec) Impulse Response NEXT models Two Piece Unger Model • Typically used for baseband signals • Uses one slope below 20kHz, and another slope for higher frequencies. • For one disturber, the Unger model uses a slope of 6dB per decade below 20kHz, and 15 dB per decade above 20kHz Simplified T1E1 Model = × 3/ 2 NEXTn xn f = × −14 × ()0.6 xn 8.818 10 n 49 n is the number of disturbers, and f = the frequency in Hz. NEXT measurements 99th Percentile Worst Case NEXT Models, N=1, & Measured Profiles -40 -45 -50 -55 -60 -65 -70 -75 Coupling Gain (dB) -80 -85 -90 1000 10000 100000 1000000 10000000 Freq (Hz) Unger Model Simplif ied Model Meas 1_2 Meas 1_3 Meas 1_4 Meas 1_5 Meas 2_3 Meas 2_4 Meas 2_5 Meas 3_4 Meas 3_5 Meas 4_5 NEXT Statistics n-GPSn-GPS statistical statistical distributions distributions for for 1 1 to to 49 49 disturbers disturbers 45%45% 40%40% 35%35% 30%30% 25%25% 20%20% 15%15% 10%10% 5%5% 2%2% 1%1% -120-120 -110 -110 -100 -100 -90 -90 -80 -80 -70 -70 -60 -60 -50 -50 CouplingCoupling gain gain (dB) (dB) FEXT Model = 2 × 2 FEXTn H channel ( f ) klf k = 8 * 10 − 20 * ()n 49 0 .6 n = number of disturbers, l = the loop length in feet, and f = frequency in Hz. 2 Hchannel (f ) is the channel insertion gain FSAN Mixed Disturber Model 1 1 0 .6 æ 3 0 .6 3 0 .6 ö Next []f = ç ()S []f X f 2 n 0 .6 + ... + ()S []f X f 2 n 0 .6 è 1 N 1 i N i æ 1 1 ö0.6 Fext[ f ] = ç()S [ f ] H 2[]f X f 2 l n 0.6 0.6 + ... + ()S [ f ] H 2[]f X f 2 l n 0.6 0.6 è 1 1 F 1 1 i i F i i Sii[f] is the PSD of the disturber, and Hii[f] is the insertion gain of the loop •No physical significance to this model •Analytical tool, with these characteristics: 1. Reduces to the identical disturber equation for disturber ≠≠ type j, if Sii = 0 or nii = 0 for all i j. 2. Reduces to the identical disturber equation if Sii =Sjj for all i≠≠j. 3. Generates nondecreasing crosstalk power as more disturbers are added. 4. Treats all disturbers equally. Intermediate Transmission Unit (TU-I) Ref - C Ref - R TU - C TU - R New - C TU-R TU-C New - R Rptr/Amp New - R Reference Y kft Z-Y kft TU-R NEXT NEXT NEXT Z kft Z-Y FSAN kft TU - C Z kft TU - R FSAN New - C Rptr/Amp Reference FEXT TU-C FEXT FEXT AWGN Noise Z kft H(f) Z-Y kft H(f) Z kft H(f) Y kft Coupling & Coupling & Coupling Crosstalk Model for NEXT & FEXT from a repeater Directional Multiplexing Choices • SINGLE BAND, FULL-DUPLEX - NEXT-LIMITED • FREQUENCY DIVISION, FULL-DUPLEX - CONSTRAINS TRAFFIC SYMMETRY - UPPER FREQUENCY BAND HAS SHORTER REACH • TIME DIVISION, HALF-DUPLEX - BURST TRANSMISSION - SINGLE BAND, REDUCED NEXT - SYMMETRY AGILE - FREQUENCY AGILE Burst Mode vs. Constant Transmissions 10BaseT LAN Burst EFM Local Loop H D MODEM L C Silent Periods: No Crosstalk Generated Can measure SNR Can ldentify Crosstalk Coupled Systems 10BaseT LAN Continuous EFM Local Loop H D MODEM L C Idle Packets: Crosstalk Generated No measurement possible Spectrum ManagerTM Patented Spectral Compatibility Method Don’t need to design for worst case – continuously measures actual coupling on every loop No Deployment restrictions, automatically ensures spectral compatibility Allows remote monitoring of Spectrum, while in service Distributed Processing Scalable – each modem performs capture and identification Centralized Management – NOC server queries modems Allows remote monitoring of Spectrum, while in service Spectrum Manager Analysis Spectral Compatibility Safe Mode If significant coupling is present with FDD system, then Robust EFM emulates the FDD bandplan National Reliability and Interoperability Council V (NRIC5) Chartered to advise FCC on Spectrum Management Issues Has made recommendation on use of spectrum above 1.1MHz: NRIC5 Recommendation For frequencies from 1.1 MHz to 12 MHz: 1. T1E1 has selected a single high- frequency band plan (known as FSAN 998) for frequencies from 0.138 to 12 MHz for use in the VDSL draft trial use standards, after substantial efforts to optimize it for multipleservice types. FG3 acknowledges the selection of this plan and recommends that this good work be recognized and supported by the FCC as the default high- frequency band plan for use in the United States. 2. We recommend that T1E1 define PSD levels, transmit power limits, and spectral compatibility criteria for signals that support this default band plan (FSAN 998). These parameters should be specified for both the central office and customer premises locations. 3. FG3 further recommends that T1E1 include the determined PSD levels, transmit power limits, and spectral compatibility criteria in the second issue of the SM standard for protecting systems using frequencies 1. 1 MHz to 12 MHz from harm. The development of the spectral compatibility criteria should assume that only Plan 998 systems utilize frequencies 1.1 to 12 MHz.