DOCSIS 3 0 US Planning Bandwidth Management

DOCSIS 3. 0 US Planning & Bandwidth Management John Downey, Consulting Network Engineer – CMTS BU

• Frequency Stacking Levels What is CM max US output with four channels stacked and do channels have to be contiguous? • Power/Hz & laser clipping • Diplex Filter Expansion to 85 MHz? Amplifier upgrades occurring now; Best to make 1 truck roll Think about diplex filters, line EQs, step attenuators, taps, etc. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2

• Allow more BW for DOCSIS 1. x & 2. 0 CMs • Limit/reduce more node splits • Introduce new HSD service of 50 to 100 Mbps • Allow migration of existing customers to higher tier and DOCSIS 3. 0 capability Better Stat Muxing © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 3

• After increasing CW to 6. 4 MHz, measure & document unequalized US MER at multiple test points in the plant Use Path. Trak Return Path Monitoring System linecard Or Sunrise Telecom Upstream Characterization toolkit • 25 d. B or higher Unequalized MER is recommended Less than 25 d. B reduces operating margin Check US MER as well as per-CM MER • Pick freq < 30 MHz away from diplex filter group delay • Make sure latest IOS version is running on CMTS • Turn on Pre-Equalization © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 4

• Increasing ch width from 3. 2 to 6. 4 keeps same average power for single carrier SNR drops by 3 d. B or more • Keeping same power/Hz could cause max Tx level from CMs and/or laser clipping/overload • Equalized vs unequalized MER readings • Modulation profile choices QPSK for maintenance, 64 -QAM for Data, 16 -QAM for Vo. IP? Max output for 64 -QAM is 54 d. Bm. V Cab up n power-adjust continue 6 • Pre-EQ affect Great feature in 1. 1 & > CMs, but could mask issues © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 5

• Correctable FEC (US & per-CM) If > 2. 5 %: minor alarm If > 5 %: major alarm • Uncorrectable FEC (US & per-CM) If > 0. 1 %: minor alarm If > 1 %: major alarm © 2010 Cisco and/or its affiliates. All rights reserved. • Equalized/PRE-EQ MER(SNR) (US & per-CM) If < 27 d. B: minor alarm If < 24 d. B: major alarm • Cable Flap-List D 3. 0 Modem Diagnostic Log Can utilize IPDR Cisco Confidential 6

• MER per US with ability to drill-down for per-CM MER • Use Return Path monitoring tools Cisco Broadband Troubleshooter (CBT) Need analyzer to read < 5 MHz for AM or ham radio ingress Path. Trak to view 5 -65 MHz for apparent laser clipping New Path. Trak card reads 0. 5 MHz - 85 MHz • Cable Flap-List monitoring for US or CM issues • Uncorrectable /Correctable FEC per US with ability to drill- down for per-CM counters • Bottom line is correctable & uncorrectable FEC If correctable FEC is incrementing, then eventually it will lead to uncorrectable FEC, which equals packet drops © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 7

CNR MER(SNR) Corr FEC Uncorr FEC AWGN Bad Bad Eventually Bad CW Carrier Bad Ok Ok Ok Impulse Noise / Laser Clipping Bad Ok Ok Bad Group Delay / Micro. Reflections Ok Bad Eventually Bad • Ingress cancellation will cancel some CPD • CPD resembles AWGN when all DSs are digital © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 8

• Frequency Stacking Levels What is the max output with multiple channels stacked Is it pwr/Hz & could it cause laser clipping? • Diplex Filter Expansion to 85 MHz If amplifier upgrades are planned for 1 GHz, then pluggable diplex filters may be warranted to expand to 85 MHz on the US Still must address existing CPE equipment in the field and potential overload RFo. G could be perfect scenario (maybe even 200 MHz split) • CM must be w-online (requires 1. 1 cm file) for US bonding • Monitoring, Testing, & Troubleshooting Just like DOCSIS 2. 0, test equipment needs to have D 3. 0 capabilities © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 9

• Freq assignments 5 to 42, 55, 65, 85 MHz ? Diplex filters, line EQs, step attenuators, CPE overload • Max Tx for D 2. 0 64 -QAM for 1 ch is 54 d. Bm. V • D 3. 0 US ch max power Tx for D 3. 0 TDMA 17 - 57 d. Bm. V (32 & 64 -QAM) 58 d. Bm. V (8 & 16 -QAM) 61 d. Bm. V (QPSK) Tx for D 3. 0 S-CDMA 17 - 56 d. Bm. V (all modulations) • Max Tx per ch for 4 freqs stacked at 64 -QAM ATDMA is only 51 d. Bm. V & 53 for S-CDMA © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 10

© 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 11

• Was only one US channel present, now up to four US chs transmitting at same time Possibly 6. 4 MHz each; nearly 26 MHz US channel loading • Lots of power hitting return path fiber optic transmitter • Probability of laser clipping is increased, especially if using legacy Fabry-Perot (FP) lasers Good idea to upgrade to Distributed Feedback (DFB) lasers, which have significantly more dynamic range • Use return path monitoring system capable of looking above 42 MHz to see second and third order harmonics • Any burst noise above diplex filter (i. e. 42 MHz) coming out of return path receiver is usually indicative of laser clipping © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 12

• Blue trace shows case of strong laser clipping • Green line represents flat US laser noise floor with no clipping • Note that this US has four US bonded channels © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 13

• Each US channel used for bonding is individual channel • Transmitters (channels) are separate Don't have to be contiguous and can have different physical layer attributes like; modulation, channel width, tdma or scdma, etc. • Frequencies can be anywhere in US passband do not need to be contiguous • It may be wise to keep relatively close so plant problems like attenuation and tilt don’t cause issues • CM will have some dynamic range to allow specific channels to be a few d. B different vs. other channels © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 14

• New conundrum raised when fiber run deeper into network RF over Glass (RFo. G) DOCSIS Passive Optical Networks (DPON) • May incorporate 32 -way optical splitter/combiners. Having a laser Tx in your house combined with 32 other houses feeding 1 Rx in the HE is addressed with lasers timed with the actual traffic from the house; unlike how it is done today where the US laser is on all the time • US bonding and/or load balancing presents potential issue where an US laser could be transmitting same time as another US laser • May be acceptable with multiple lasers transmitting same instant in time, if they are carrying different frequencies, • Will S-CDMA pose same problems? This multiplexing © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 15

CMTS US 0 @ 24 MHz 4 -Way Fiber Optic Rx 1 Filter CMTS US 2 @ 31 MHz Amplifier 4 -Way Fiber Optic Rx 2 CMTS US 1 @ 24 MHz • Attempting to “share” one US port across two other US ports Can cause isolation issues Load balance issues (ambiguous grouping) © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 16

• 17 d. B at 5 MHz & 32 d. B at 1 GHz • Eliminates max transmit CMs CS(CEQ) tap • Eliminates high DS tilt to TV 26 350’ 1. 5 d. B 23 500’ 2 17 FEQ w/ US pad 600’ 2. 5 Input 17 Reverse 43 d. Bm. V transmit level @ the tap 42 39. 5 4 Step Attenuator or EQ tap 29 38 X PIII. 5” cable. 40 d. B @ 30 MHz A total design variation of ~14 d. B! © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 17

• Running D 3. 0 CM in low modulation scheme allows higher power • Use D 3. 0 CM in 2. 0 mode Single frequency on D 3. 0 CM offers 3 d. B higher power • Using SCDMA with more codes may also allow higher Tx power, but depends on implementation • Minimum level of 17 d. Bm. V (24? ) could cause issues in lab environment or HE test CM Pmin = +17 d. Bm. V, 1280 ksym/s Pmin = +20 d. Bm. V, 2560 ksym/s Pmin = +23 d. Bm. V, 5120 ksym/s © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 18

• Cost effective and faster time to market Decrease costs today – deploy DOCSIS 3. 0 later with no additional CMTS investment! • Targeted insertion of D 3. 0 Leverage existing US chs while adding more US capacity Load balance 1. x/2. 0 and enable D 3. 0 when needed Minimizes capex & opex • Leverage D 3. 0 bonding for D 2. 0 tiers & services Better stat-mux efficiency Improved consumer experience © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 19

• Long term D 3. 0 service planning Insure optimized frequency allocation Enable seamless upgrade to higher D 3. 0 tiers Wire once Add QAM chs as tiers or service take-rates go up • End-to-end solution minimizes risk CMTS, QAM, and CPE • Account for phy connectivity, not just ch capacity Not advantageous to combine noise to satisfy connectivity • Fix Max Tx issues now Design for tight “bell-curve” (43 -48 d. Bm. V), if possible • Good News – ECR to increase US Tx levels 61 d. Bm. V max, with 3 d. B typical © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 20