The Spectrum Newsletter of the Rocky Mountain Chapter

Transcription

1 The Spectrum Newsletter of the Rocky Mountain Chapter August 2011 Featured articles: 1. Ron Hranac, Cisco Systems - Technical leader, Broadband Network Engineering, for Cisco Systems. Constant power-per-carrier 2. Jorge Salinger, Comcast Cable - VP, Access Architecture: Tell me again, what is CCAP? SCTE Update Tom Gorman Board, National At Large Director and past Chair As of July 29, the voting window for region 2 representative is over. We re waiting to see who will be the next regional leader. Both candidates (Maria Popo and Nick Segura) are very capable, engaged and enthusiastic about SCTE and our region. It s great to note that they are both Rocky Mountain Chapter members as well. The national board of directors met last week at SCTE headquarters in Exton, PA. It is amazing to see all the things that the staff of SCTE is working on such as alternative energy engineering, new certification programs for telecom facilities, new professional development primers, and a continual upgrade to the SCTE website. Speaking of websites, I hope you ve taken a moment to visit the RMC new and improved website. If not, just go to to find out all that is happening in the chapter. Also, don t forget to go to our Facebook page and like us! 1

2 Save these dates! 2011 Chapter Events Pre-seminar openers (10 to 15 minutes) are planned before each event and subjects will include: Telecom Industry current Events Professional Development, Benefits of Take-a-ways Getting that one thing Certification out of this seminar Membership benefits Safety tie-in to seminar topic Scholarship opportunities Aug 17 th Grand Junction, CO Albuquerque, NM Digital Testing and Measurement Hands On Sept 15 th Comcast Inverness Home Networks and Englewood, CO Technologies Oct 13 th Comcast - Iliff Denver, CO Did you know? What s Happening all Digital World February Charter Communications Business Services 2012 Greenwood Village, CO Al Silva see below for details ***See Below for details Ron Hranac BICSI, Building Industry Consulting Services, International August 17th - Rocky Mountain Chapter Seminar When? August 17, :00 AM to 12:00 PM Morning Session 12:00 PM to 1:00 PM Lunch 1:00 PM to 4:00 PM Afternoon Session What? Who? Where? How Much? Digital Signal Measurements and Troubleshooting CATV Digital Signal measurements with hands on practice. Measurement techniques, common problems, and symptoms. Overview - practice of problem diagnosis utilizing Constellation, BER, MER, Home Cert, and other troubleshooting techniques. Al Silva, Sales Engineer, JDSU Comcast Facility, Albuquerque New Mexico 4611 Montbel Place NE Albuquerque, NM Sandia Conference Room Free - for SCTE Members -If not already a member become one for $68 $10 for non-members. Lunch is provided. There will be certification testing available The material covered is most relevant to BPS Certification Please contact us with any questions: Rex Kohart (303) Rex_Kohart@cable.comcast.com Steve Murphy (720) Steve_Murphy@cable.comcast.com 2

3 Sept 15th Rocky Mountain Chapter Seminar 'Home Networks and Technologies' Live in-person and simulcast via web conference!!! When? Sept 15, :30 AM to 9 AM On-site registration and check-in 9:00 AM to noon Presentations and discussion What? As cable operators and industry suppliers, we already encounter many services that require an understanding of home networks and technologies. This session provides an opportunity to understand current and next gen HN technologies from a uniquely qualified panel, including: MoCA technology, including background, versions, uses and interoperability Use of MoCA in cable, such as set-top applications, gateways and bridges Wi-Fi technologies and applications for HSD, security and video Mixed approaches: wireless/wired networks, use cases, challenges and IEEE P Presenters: Dr. Tom Lookabaugh Dr. Rob Howald Greg Fisher CTO, Entropic OCTO, Motorola CTO, SMC Where? Comcast Inverness Dr West, Englewood Lady Bell Conf. Room Directions to: 183 Inverness Dr West - This seminar will also be webconferenced' Register here: Webinar registrants will be sent a link to attend at time of registration. Jorge Salinger (215) Jorge_Salinger@cable.comcast.com Dave Krook (303) davidjkrook@gmail.com Nick Segura (303) Nick.Segura@chartercom.com 3

4 The annual RMC Symposium an outstanding success: 2011 SCTE Rocky Mountain Chapter Symposium - June 14 & 15, 2011 The annual Rocky Mountain Vendor Symposium was held once again at the Inverness Hotel, Golf and Conference Center in Englewood, Colorado where over 275 attendees (vendors and participants) were in attendance. Once again, the weather cooperated and we woke up to bright sunny skies on Tuesday for the annual Golf scramble which was sold out and supported by 144 golfers. Upon completion of the golf scramble, participants were treated to a very delicious lunch sponsored by Huawei Technologies.. Golfing at the Inverness Golf Club is always a highlight of the event and once again it proved to be spectacular. While the golfers were out playing the course preparations were being made in the exhibit hall and Cable Tec games. Later that evening after a very tasty welcome reception which was sponsored by BigBand Networks, the annual Cable Games event kicked off with forty six technicians from US Cable and Comcast from locations in the Denver Metro locations (North, East and West), Northern and Southern Colorado and regional engineering. Steven Schehr from US Cable took first place honors with Matt Maddock from Comcast East, picking up second followed by Josh Speiser from US Cable in third place. Row (Front kneeling) Left to Right; Steve Schehr - US Cable Overall Gold; John Nededog Comcast; Jason Patrick - US Cable; Scott Sullivan Comcast; Josh (Spencer) Speiser - US Cable Bronze Overall. Back Row (Standing) Left to Right; Rick Shaver Comcast; Matt Phillips - Comcast; Les Burch - Comcast; Matt Maddock Comcast Overall Silver; Rick Reed Comcast; Curtis Courtney Comcast; Gregg Gallegos Comcast; Richard Kotarek Comcast and Brad Jensen - Comcast Cable Games winners Top three Steve Schehr Matt Maddock Josh Speiser US Cable Comcast-East US Cable 4

5 Once again, with the full support from our Vendor community and the organization of Dave Krook and other board members, the CableGame events were outstanding with the best of the best showing off their talent. The following day kicked off with a continental breakfast sponsored by Cheetah Technologies with the show floor opening soon thereafter revealing a full showcase of reliable products and services staffed by vendor service level experts. The exhibits were first class and foot traffic was steady. During the morning, a Technical session was provided, Greening the Network From the Industry and by the Industry with around 35 attendees who were treated to a look into the future by industry experts Derek DeGiacomo (Director of Information Systems SCTE); Daniel Cooper (Sr. Director, Technical Operations Time Warner Cable and Chairman of the SCTE SMS technical subcommittee) and Jim Heidenreich (Vice President of Product Management Alpha Technologies). New to this year s symposium, was Tom s Tent whereby board member Tom Gorman led a number of vendors and executives into a discussion about current events. Tom s Tent was very well received and the chapter looks to build upon its success. Tom s Tent Comcast West Division Execs Tom s Tent Richard Covell Stories from the Past Exhibit Hall Vendor Showcase Golf Outing Luncheon and Awards Thanks to all of you who attended, to the Rocky Mountain Board members and Friends of the Board and to the rest of our vendor community for their support and hard work to make this symposium once again one of the best shows. Mark your calendars 2012 SCTE - Rocky Mountain Chapter Symposium June12-13,

6 Technical Forum Constant power-per-carrier Ron Hranac, Cisco Systems Ron is CT's senior technology editor and has been writing for us for more than 20 years. He's been an SCTE member since 1979 and is currently a technical leader, Broadband Network Engineering, for Cisco Systems. Prior to joining Cisco, he held management positions at companies including High Speed Access International and Coaxial International. He also has held many positions on the SCTE board and in local chapters and has the distinction of being the first person in the cable industry to be certified in SCTE's BCT/E program (in 1987) and became the SCTE's first Fellow Member in Originally appeared in the January 2011 issue of Communications Technology. Reproduced with permission of the author. Many cable modem termination systems (CMTSs) are configured for what is known as constant powerper-carrier operation in the upstream. This mode of operation ensures that upstream digital channel power remains the same value when symbol rate and channel bandwidth are changed. Constant power-per-carrier is in contrast to another supported mode of operation, constant power-per-hertz, which maintains a constant carrier-to-noise ratio (CNR) when the channel bandwidth changes. Note that constant powerper-carrier and constant power-per-hertz operation are not the same as long loop automatic level control (ALC), which is a CMTS-cable modem interaction mechanism to maintain the desired RF signal level the commanded nominal receive power at the CMTS upstream port as the return path s attenuation changes because of temperature variations and other factors. The default commanded nominal receive power is 0 dbmv in most, if not all CMTSs. Constant power-per-carrier operation causes a fair amount of confusion, largely because of the observed change in the upstream signal s haystack height as seen on a spectrum analyzer when channel bandwidth is changed. The haystack height change means CNR also changes, accompanied by a change in the CMTS s reported upstream SNR actually modulation error ratio, or MER. What the heck is all of this change if constant power-per-carrier operation is supposed to maintain the same digital channel power when channel bandwidth is changed? The following example might help to clear up some of the confusion. Let s say an existing upstream signal is configured for a symbol rate of 2.56 million symbols per second (Msym/sec), which yields a channel bandwidth of 3.2 MHz. Connect a spectrum analyzer to a suitable test point near the CMTS s upstream port so you can observe the received signal s haystack. Note the displayed height of that haystack on the spectrum analyzer. Now switch the upstream signal s symbol rate to 5.12 Msym/sec (6.4 MHz channel bandwidth). For a brief amount of time the height of the haystack will remain as before. At this instant the now-wider signal s digital channel power is 3 db greater than the narrower bandwidth signal s was, even though the displayed haystack height has not changed. Double the haystack bandwidth means double the digital channel power! 6

7 Because of constant power-per-carrier operation, after the channel bandwidth is doubled to 6.4 MHz the CMTS will command cable modems to reduce their transmit power by 3 db in order to maintain the same digital channel power that existed when the upstream signal s bandwidth was 3.2 MHz. The haystack s displayed height on the spectrum analyzer will drop 3 db, which indicates the CNR also has dropped 3 db. Remember, a quadrature amplitude modulation (QAM) signal s CNR is the haystack height in db above the displayed system noise floor as seen on a spectrum analyzer just make sure the displayed noise floor is system noise and not test equipment noise. In a pure additive white Gaussian noise (AWGN) environment with no other impairments, the MER will drop 3 db because of the 3 db CNR drop. However, in a typical real-world upstream the MER is often seen to go down more than 3 db, sometimes a lot more, because of linear distortions in the channel. The 6.4 MHz bandwidth QAM signal is somewhat more susceptible to linear distortions than the 3.2 MHz bandwidth signal was, causing the MER to drop more than just the 3 db CNR-related reduction. Alright, with constant power-per-carrier operation a doubling of channel bandwidth causes the CNR to drop 3 db, and the MER to drop at least 3 db but probably more. What to do? One can make up for the 3 db CNR reduction by changing the CMTS s commanded nominal receive power from the default 0 dbmv to +3 dbmv, or installing a 3 db pad as closely as possible to the input of the CMTS s upstream port. Either will force the cable modems to transmit 3 db higher than before, making up for the CNR hit and the CNR-related MER degradation. This may not be necessary in a properly designed and well-maintained plant. After all, modern HFC networks are easily capable of producing upstream CNR 30 db or higher. If the upstream CNR was already high enough, there may be no need to tweak cable modem transmit levels when switching upstream channel bandwidth, at least to compensate for the CNR reduction. A word of caution when forcing cable modems to transmit at higher levels: If there are cable modems in the field already operating at their maximum transmit level, those cable modems won t be able to increase their transmit level the desired 3 db. They re already maxed out. Here you may see a couple gotchas. The affected cable modems upstream signals will be received at the CMTS at least 3 db lower than other cable modem signals, and will have per-modem CNR and MER values that are also lower than other cable modems. The affected cable modems may not be able to stay on line if their signal levels hit the CMTS too low, depending on CMTS configuration. The latter may have to be tweaked to allow low upstream receive level cable modems to remain on-line. Since the vast majority of high transmit level cable modems are that way because of subscriber drop problems, identify the culprit cable modems and sort out what s causing them to be maxed out in the first place. If the upstream MER dropped more than 3 db when doubling channel bandwidth, changing cable modem transmit levels won t compensate for MER degradation related to the presence of linear distortions in the channel. Two options exist here. One is to turn on cable modem upstream pre-equalization, which is quite effective at dealing with upstream in-channel linear distortions. DOCSIS 2.0 and later cable modems support 24-tap adaptive pre-equalization, which is superior to DOCSIS 1.1 s 8-tap adaptive preequalization. DOCSIS 1.0 cable modems generally do not support any pre-equalization. The other option is to troubleshoot the linear distortions and fix what is causing them. For this you ll need specialized test equipment, since conventional spectrum analyzers and signal level meters can t display linear distortions. Several manufacturers have available QAM analyzers, combination QAM/spectrum analyzers, and even spectrum monitoring platforms that are suitable for troubleshooting upstream linear distortions. Alternatively, if your company has deployed an internal tool based on CableLabs Pro-Active Network Maintenance best practices guidelines (see my October 2010 column, A Novel Way to Troubleshoot Linear Distortions, you can troubleshoot them with that tool. 7

8 Tell me again, what is CCAP? Jorge Salinger, Comcast Cable VP, Access Architecture On June 14 th, coinciding with the kick-off of the NCTA s 2011 Cable Show, CableLabs released an updated version of a technical report that outlines the requirements and operations modes for the headend device now called Converged Cable Access Platform (CCAP). This update of the CableLabs document includes all the previous requirements, and adds descriptions for various operational modes intended to clarify how the same CCAP device may be used by various MSOs in different ways. The CCAP device was previously referred to as CESAR by Time Warner Cable, and known as CMAP within the set of specifications developed by Comcast and its spec partners Cablevision, Charter, Cox, Liberty/UPC, NCTC, Rogers and European MSOs via representation from Cable Europe Labs. Moving forward, the device will be uniformly known by the new CCAP name. The updated technical report containing additional operational modes and the use of a unique and agreed upon name is intended to positively outline how the same device can be used by various MSOs in different ways. For example, devices compliant with the CCAP requirements could be developed in various sizes, or the same CCAP device could be used in one location with video encryption within the CCAP itself and in another without, and other such varying use cases for the same device. As always, CCAP was specifically conceived and intended to support the growth in the number of QAM channels used for narrowcast services, such as Video on Demand or Switched Digital Video given the success of the services and the expansion of HDTV content, and the availability of channel bonding in DOCSIS 3.0 to support newer, higher bandwidth data services. And, as MSOs continue to reduce the size of service groups to make more efficient use of their networks, and consider the deployment of advanced services such as IP-based video and network DVR, even more QAM modulators are needed. CCAP devices will provide the necessary QAM-per-RF-port and port-per-chassis density to support this growth while requiring less space and power than currently available equipment, reducing capital and operational costs and simplify operations. CCAP devices will implement both the Edge QAM and CMTS functions in a consolidated platform. As a result, each CCAP downstream port can provide QAM channels for all digital services as shown in the figure. CCAP is designed for high availability, full spectrum or overlay HFC networks, supporting any MPEG-TS or DOCSIS services via configuration. CCAP leverages existing technologies such as CableLabs DOCSIS 3.0, DRFI, etc., incorporates newer ones such as Ethernet optics (EPON, in particular), and leverages the experience acquired over many 8

9 decades of technology evolution for cable networks, including new functions and features described in the CCAP Specifications. Given the cost and operational benefits, many MSOs would begin deploying CCAP-type equipment immediately, if possible. It is not expected that this effort to consolidate the industry requirements into a single set of documents will have an impact on the timeline for availability of equipment. Because of such latent benefits, equipment development is progressing at a very fast pace. Initial availability of equipment for laboratory and field tests is expected by late in 2011, and early deployments could begin as early as Substantial equipment availability is anticipated by The updated technical report is available from CableLabs, and can be found at An additional upcoming specification from CableLabs will include new configuration and management technology for the CCAP, and other specifications are being considered. And, as has been the case with CMTS and Edge QAM equipment, additional MSO-specific requirements above and beyond the CableLabs CCAP specs will be described by individual MSOs as needed, and will be available from the respective MSOs. Hopefully this brief overview was useful. Feel free to reach out to me via to jorge_salinger@cable.comcast.com for additional questions. Scholarship Opportunity By Joe Thomas In these hard times job loss is collateral damage to the effects of the credit, housing, and energy issues affecting our country. The Rocky Mountain Chapter is proud to be in the position to offer its members a way of providing some security or opportunity in these times. We believe that through a scholarship program we can assist members wanting to differentiate themselves from their peers through education and certification. Why does the RMC support a Scholarship Program for its Members? We make it easy on our members to enroll, test, and certify for SCTE certifications covering a wide range of job classifications and skills. Certificates range from residential installation practices to digital video engineering and all points in-between. Visit our web site at to get more details. Our scholarship application should take you less than 15 minutes to complete and you'll just need to add two letters of recommendation before sending to us. Why should I certify with the SCTE? The SCTE is the leading source of certification specific to our industry. There are over 15,000 worldwide members and more than 3,000 members enrolled in SCTE certification programs. It is the most comprehensive and widely recognized program in the industry. In this competitive job market any edge you can give yourself will help you rise above the masses when being considered for a promotion or a new job. Believe me when I say, that experience and "time in the trenches" is invaluable to our employers and it has let many of us earn a great living in a great industry. However, there are large numbers of people out there looking for job that have time and work experience on their side. Unemployment is regular and competition more fierce. How will you secure your current position or prepare yourself for the next promotion opportunity? Today you need something else to demonstrate your commitment to expanding your work knowledge and skills. Otherwise your resume looks just like the two dozen other ones sitting on a hiring manager s desk. College classes are another avenue for motivated individuals. A college degree is a fantastic goal and the SCTE Foundation has funds available for grant to help you here as well. Consult the web site for more details. But College is not for everyone and the time, family responsibilities, and other constraints are 9

10 endless. SCTE certification allows you to simply test at a local seminar after home studying for as long as you wish. There is no set class schedule or deadlines. The RMC offers testing at about every seminar. Certification is a viable route for many whom have full time jobs but yet want to advance and demonstrate their knowledge. The Rocky Mountain Scholarship program covers membership cost, testing fees, and peer recognition. The details of how to apply for a scholarship from the RMC is available on our web site: Elected Board of Directors Name Company Position Phone Number Frank Eichenlaub eichenf@cisco.com Cisco Systems Board, Web Master, Region II Director Tom Gorman Tom.Gorman@chartercom.com Charter Comm. Board, Ntl At Large Dir and past Chair Lane Johnson l.johnson@cablelabs.com CableLabs Board, Treasury Committee Rex Kohart Rex_Kohart@cable.comcast.com Comcast Board Dave Krook davidjkrook@gmail.com Vice President Hugh Long hlong222@comcast.net Charter Comm. Secretary Steve Murphy Steve_Murphy@cable.comcast.com Comcast Treasurer Jorge Salinger Jorge_Salinger@cable.comcast.com Comcast Board Nick Segura Nick.Segura@chartercom.com Charter Comm. President Frank Wimler Frank.Wimler@Chartercom.com Charter Comm. Board Supporting Associate Board Members 2011 Definition: Somebody who supports the functions of the local chapter by participating in meetings provides input that helps drive board decisions, volunteers, speaks supportive, and generally those who make an impact through their involvement. Associate Board Members do not have the ability to vote. Name Company Position Phone Number James Baron James.Baron@chartercom.com Charter Comm. Board Associate Kevin Bland Kevin.Bland@chartercom.com Charter Comm. Board Associate Steve Brown Steve80134@comcast.net InterMtn. Consult. Board Associate Richard Covell rgcovell@msn.com TTSI Board Assoc./Spkr Judy Donavan jdon589029@aol.com Donavan Consulting Board Associate Paul Eisbrener peisbrener@jonesncti.com Jones/NCTI Board Associate Rex Gerhardt rgerhardt@terabitcomm.com Terabit Comm. Board Associate Ron Hranac rhranacj@cisco.com Cisco Board Assoc./Spkr Robert Kostelny rob.kostelny@comcast.net Board Associate Debbie McManis deborahmcmanis@comcast.net Board Associate Joe O Fallon Joe.OFallon@lineagepower.com Lineage Power Board Associate Maria Popo maria.popo@ubeeinteractive.com Ubee Interactive Board Associate Dave Robinson drobinson@ipitresources.com IPIT Resources, Board Associate & Inc. Newsletter editor Neil Serafin neil@cabtel.com CabTel Board Assoc./Spkr Steve Snider stephen_snider@cable.comcast.com Comcast Board Assoc./Spkr Jim Stewart jim_stewart2@cable.comcast.com Comcast Board Associate Joe Thomas jthomas@infinera.com Infinera Board Associate Mark Thompson thompson@commscope.com Commscope Board Associate Stephanie Trotter stephanie.trotter@twcable.com Time Warner Board Associate