This is an impaired service, discussed elsewhere on my site on DOCSIS 3.0 issues. If the modems are not doing this, talk to your modem vendor and tell them to fix their firmware. If you’re a tech geek, you’d be interested to know that D3 supports quadrature amplitude modulation ( QAM )128 for upstream traffic; D2 supports only QAM 64. So you will need to keep your DOCSIS channels above 111 MHz recommended. Acceptable SNR Levels (dB): If QAM64, SNR should be 23.5 dB or greater. To illustrate, D3 spectrum spans 108 MHz – 1.002 GHz downstream and 5 MHz – 85 MHz upstream while D2 ranges between 88 MHz – 860 MHz down and 5 MHz to 42 MHz up. It is then the cable modem’s responsibility to re-synchronize the incoming packets based upon the sequence numbers. Again, these become more cumbersome methods, but would reduce the 20-40 minute time. Good Upstream power levels are within 38-48 dBmV. Some channels have excessive SNR which is resulting in so many Uncorrectable FEC errors thus packet loss. Specifically my question is the following scenario: A person lives in a multi dwelling unit with a tap providing cable service to about 100 people. you can help me, explain why the uBR10k required to use the frequencies used continuously, for configuration D3.0 when channel bonding have necessarily to user continuous frequency. Why? If Wi-Fi is the lifeblood of your connected lifestyle, your modem is the heart that keeps it pumping—which makes your modem's compatibility with your broadband service crucial. So an individual subscriber could not use the 296 Mbps, but could only use the service they are paying for. This will save your modem a lot time in searching for the correct DOCSIS frequency. Nice explanation regarding DOCSIS 3.0, as I am a new to this technology, I need some information regarding, if there is particular modem is offline ( when we see them using show cable modem) or any interface issue or any issue related to frequency lab lab laa…, then how to do some real time trouble shoot , so can we identify the particular error, and how to fix it. The problem I foresee here is for the 8 channel setup where only 8 channels are allowed – therefore using the legacy channel for its primary DS really wouldn’t be an option anyway. India Vijay Vadnere The other answers here are vastly more complete than I could hope to be. I will add my answer only due to an A2A. Some of the older DOCSIS 3.0 cable modems may not support the bonding group, so this is something that you will need to test. The number of downstream bonded channels has been 8 since DOCSIS 3.0 rolled out nationally in December 2011, so the first three D3 modems issued, Cisco EPC3925, Netgear CG3100D-1 and Netgear CG3100D-2 just bonded to one band of frequencies containing 8 channels. It is possible to have 1 mac domain with all 8 DSs as primary and the proper wideband and integrated interfaces. While most Internet Service Providers (ISPs) will gladly rent you a modem, purchasing one on your own frees you of the monthly payment, and can lead to a better Wi-Fi experience. When I use my SB6120, it bonds 4 channels and is able to maintain a completely steady connection, superior to the 8 bonding capable modem, the SB6141. gjett1In regards to gaming on the AWS servers, in a nutshell, we were able to isolate the problem to the AWS 54.239 (and possibly 52.239) network.We found that by pinging with a packet size somewhere between 128 bytes and 256 bytes and higher, the packet loss began at the AWS 54.239 (and possibly 52.239) network when the source IP address originated from the Cox network. for code error rate before? Which cable operator do you work for? Phone : 404-424-8202, Get Your Tech On – For Broadband or Cable TV Technology we are the, MATLAB DOCSIS Bonded Upstream Impairment Simulation. pl suggest changes to resolve this problem. I have tried a few things so far but eventually had to take Integrated 1/1 downstreams out of the fiber node so the modem would come online. One of the cool things with DOCSIS 3.0 channel bonding is that data is “striped” or effectively sent down across the number of available bonded channels on the modem. There are things you can do to help in your own home. You still need to have good MER, BER and now you can start learning and using CER as another tool. This will ensure your cable modem receives the best signal possible and transmits the highest quality signal. Because many legacy Downstream plants start their DOCSIS channels above 500 MHz, so it reduces the time to find a DOCSIS channel and lock. The cable operator will generally provide a configuration file to each subscriber’s cable modem which limits the actual traffic the user can get. I am able to do this because we are not utilizing our system until our WAN is upgraded. Thanks, Ken. Duc. So once they found that 400 MHz channel and the possible upper channel for load balancing, you should be okay. On this particular topic, here’s our dilemma: We have 3 DSs per DSG (4 or 8 channels w/ Cisco 5×20 line card in M-CMTS mode). So Cisco has built this into their CMTS. Unfortunately this will impact all subscribers, but would be done only to the upstream channels with high FEC errors. If QAM256 and DPL(-15 dBmV to -6 dBmV) SNR should be 33 dB or greater. This document describes how to check the three signal levels to be within the acceptable level for the modem operate properly. Channel width: Downstream: All versions of DOCSIS earlier than 3.1 use either 6 MHz channels (e.g. Dear Brady, One side of the splitter feeds your cable modem and the other feeds the rest of your house. +919822054008 Same for the 5×20 cards, but I generally recommend the MC20x20 cards over the MC5x20 cards because performance in the MC20x20 cards is far superior over the 5×20 for a number of reasons. Downstream power level should be no more than +/- 5 dBmV, according to the comcast tech who just came out to fix my signal. LOL on the last part. https://volpefirm.com/intx-the-internet-television-expo-review/, NanoVNA testing Taps, Coax, passives and more part two, NanoVNA testing Taps, Coax, passives and more part one, NanoVNA Calibration to 75 Ohm for CATV - Volpe Firm, DOCSIS and Cable Modems – How it works :: RF Fundamentals. It was determined that a 60 MHz bandwidth would be reasonable for cost effectiveness based upon existing hardware at the time of the specification. Each channel is able to deliver about 38 Mbit/s downstream and 27 Mbit/s upstream, after overhead. Thanks, Hi, I have Cox gigbit service but I only get around 630mbps max (sometimes 590mbps). The 2.4 GHz frequency band has room for three non-overlapping bonded channels. In the North American DOCSIS standard the bandwidth is 60 MHz. BER must be equal to or better than 1×10-8 and codeword error rate (CER) must be less than or equal to 9×10-7. This has created a problem with new wideband CM’s DS selection process to the point where it can take up to an hour for modems to find a legit primary channel – average is 20 – 40 minutes or so. Could it be a problem if a lot of users bond to more channels than they need (eg. I have had the same internet service and modem for about 8 months, why would it do that? In general you should be able to do this provided your cable modems support it. You can talk to your Cisco support engineer and they are able to add custom code for modem steering in special cases like this. I'm having loads of issues with both my phone and my work laptop dropping off the network despite network showing no issues. Upstream: DOCSIS 1.0/1.1 specifies channel widths between 200 kHz and 3.2 MHz. I see all the channels aren't locked in so it could be as simple as a loose/rusted connector. Each outgoing packet from the CMTS is tagged with a sequence number. The data will still get across the remaining bonded channels just fine, however if the CMTS is doing its job properly. Channels bonded can be wired links such as a T-1 or DSL line. Click to see full answer. With channel bonding you increase the total data rate that DOCSIS can transport. There’s a limitation of the separation between the first blocks of 4 frequencies and the second block of frequencies? Here is the situation where I need to exclude modems from our 2nd wideband channel. i installed Cisco 10 K CMTS and having approx 20K online subscribers. Connection Issues - low power on downstream bonded channels on ‎07-07-2020 11:58. For a single DOCSIS QAM channel, for example, you could transport 37 Mbps. This is called Downstream Channel Set (DCS) and is truly analogous to upstream load balancing. That did increase to 9 when the Gateway MAX (Netgear C6300) was first released. Hi Davi, So the four channels you are configuring must be within a 64 MHz bandwidth or even a 60 MHz bandwidth, depending upon how the manufacturer interpreted the specification. Channel bonding simply means that the CMTS knows that there are four or more RF signals within a 60 MHz passband (greater if more than four channels are bound). Depending on the IOS version of the 10k you have certain restrictions where you can place the DS frequencies. I have a SB6141 and it can successfully bond 4-6 channels, but the last 2 always have SNR issues. So to summarize you will still get great throughput with the DOCSIS 3.0 modem with 6 channels. In the Downstream Bonded Channels section, identify the Modulation and Power to find verify SNR levels are within the acceptable range for each downstream channel. Consider it a self-healing mechanism that can come into play that gives you an opportunity to resolve a problem on that particular frequency. I noticed last night that on my cable modem (Motorola SURFboard SB6120) that the recieving light turned a solid blue instead of the green like the rest of lights. Assuming a fair amount of modems (500 modems), would there be a throughput/performance savings when limiting Docsis messaging to the first 8 Downstreams? Within 802.11n deployments this translates into a theoretical throughput of 54 Mbps. I have a SB6141 cable modem. Additionally, the specification has a recommendation that 999 MHZ should be the high end frequency of DOCSIS 3.0, fully utilizing a 1 GHz plant. But if you have have more than two, all bets are off depending upon your cable modem vendor. What are the acceptable Cable Signal levels for the SB6183 Modem? North America) or 8 MHz channels ("EuroDOCSIS"). Watch industry leaders on youtube please hit the subscribe button and let us know what you think and remember to share. It does not fix the plant, because your codeword errors and thus CER will go up considerably on that channel, your overall data rate will drop for the DBG, but data will still go through on the other channels at a maximum rate. A 16x8 cable modem, for example, can deliver 608Mbit/s downstream (16 ch. You will either be dealing with 64-QAM, 256-QAM or a mix of both in your downstream bonding groups, which must be in a 60 MHz bandwidth. I believe the solution is playing around with the load-balance excludes but we’ll have to see. Yes, it is very common to do 4 or 8 DS channel bonding on the MC20x20 cards. Do you have any suggestions on how to improve the DS selection process with this setup? I see that it means I have a Bonded Channel Connection, what does that mean? Hi Brady, While conceptually simple, the principle of combining multiple downstream DOCSIS channels together to carry the same user data must have tight constraints in order to preserve the integrity of the data and have the data arrive at the correct subscriber’s device and in sequence. Well this is new to the DOCSIS 3.0 specification and is something that is quite over due since BER is nearly impossible to measure in a live DOCSIS plant while CER can be obtained right from the CMTS. There is a secondary benefit to configuring all downstreams as primaries and that is you will be able to fully test each DOCSIS primary channel using your legacy DOCSIS 2.0 hand-held test meters. Thanks for your interest. This is in the I-CMTS configuration. Does it make a difference where the bonded frequencies are placed in related to the narrow band forward frequency? Downstream SNR levels are read at the modem on the downstream data channel and can be viewed using the modem diagnostic screens. vijuv20001@gmail.com Catch Hangout on April 8th and well cover this question. We would be glad to work with your cable operator if they contact us directly, however, I am sure they have someone on staff who will resolve your issue. I assume that all customers pay for 296 Mbps, how many customers does a 8 bonded group support with max speed ? This article will cover both the physical layer aspects and DOCSIS protocol aspects that enable channel bonding. The Docsis 3.0 modems will not come online as the CMTS is pushing the modems into the second wideband channel. I have 4 frequency blank are 500, 508, 588 and 596 Mhz (Ref EU), so i want config for MC20x20-ubr10K together 4 this frequency per Port DS, but when config IOS request 4 frequency continuous, why ? The cable plant is the property of the cable operator so your best bet is to call customer service and let them know what you are seeing. Downstream Channel Bonding is perhaps the ball bearings of DOCSIS 3.0, enabling subscriber data speeds in excess of 160 Mbps (4 times that of previous DOCSIS versions) When you configure a DOCSIS channel as a primary it must carry all of the DOCSIS protocol overhead, which is about a 15% to 20% loss of user data. Our’s CMTS system using Cisco uBr10k, when configuration CMTS, IOS required use 4 frequency consecutive, if using 4 different frequencies IOS not accept. Video conferencing calls, even just on voice only are now practically impossible. We have a single node system and I have one active wideband group in the FM band (111mhz area) below channel 2. We currently have Docsis 2 and are upgrading to docsis 3. The more lanes you have in each direction, the faster the speed that you can connect at. What is the drawback then? Also available on iTunes and Google Play see podcasts “get your tech on”. Arris Group is aiming to ship its Touchstone Telephony Gateway TG1672 -- which features dual-band Wi-Fi and uses Intel's Puma 6 DOCSIS 3.0 chipset with support for up to 16 downstream bonded channels to deliver up to 640 Megabits per second -- in the fourth quarter of 2012. Therefore, we can’t make every DS channel primary capable – not allowed. In respect to this, what is a bonded upstream channel connection? So we have only 20×20 linecards and 1 DS freq. Planning ahead is always better than letting the modem wonder around your network. 2) In a token ring network, a computer station is downstream from any station through which the token on the ring has already passed. Don’t put anything between your cable modem and the cable operator, like an amplifier – that is sure to cause problems! Downstream SNR (Signal to Noise Ratio) refers to the signal being sent in relation to the noise on the line. We are hoping to add 117 mhz and 99 mhz. Acceptable SNR Levels (dB): If QAM64, SNR should be 23.5 dB or greater. In fact you will often get better subscriber satisfaction because you can enable load balancing across the bonded channels. Will 99 mhz and 105 mhz work for downstream channels as I have read some articles that say to start at 111 mhz. Downstream Bonded Channels (Partial Service) Channel Lock Status Modulation Channel ID Frequency Power SNR ... Upstream Bonded Channels. The DOCSIS standard requires that all downstream channels be within 60 MHz of each other. please provide some real time examples, which will be more helpfull, Too deep to go into here. As soon as you think you have everything figured out you are working overtime again because the unknowns slap you in the face! For 8 bonded channels you could transport 296 Mbps. (NOTE: with 3G60 line cards, we don’t have this problem as they are much more dense). However, a cable modem does have memory. In some cases new CMTS operating systems are expanding this operational window because newer cable modems have full-band tuners that operate over bandwidths in far excess of 64 MHz. ! Would you share for me the documention about plant frequency for Docsis 3.0 ! Downstream Channel Bonding is perhaps the ball bearings of DOCSIS 3.0, enabling subscriber data speeds in excess of 160 Mbps (4 times that of previous DOCSIS versions). Enter, Refresh the page at least twice to identify variations in. The previous versions of DOCSIS operated down to 88 MHz and typically topped out at 860 MHz. I believe that you are asking if DOCSIS 3.0 with channel bonding can still support DOCSIS 2.0 and 1.x modems or if it even makes sense. Find out about events or articles by following us on Twitter, LinkedIn or Facebook too. Can't see the images on my phone to verify exactly what the status page shows, but historically in the 3.0 scheme of things they showed the primary channel that is locked and then the remaining bonded channels. So when you have the ability to later configure a DOCSIS downstream channel to a secondary channel, the secondary channel no longer carriers the excessive DOCSIS overhead, except for some minimal synchronization information, and so you can now transport significantly more data to your end subscribers. CER can be computed as follows: Keep an eye on CER to be a new metric for equipment manufacturers and test vendors to be using moving forward in addition to BER and MER. Hoi, Het is al weer een tijdje dat ik op de community iets schrijf, nu iets wat hier in huis voor problemen zorgt. TCP/IP windowing acknowledgments will take care of any lost packets at Layer 3, however for UDP flows, such as voice and video, those packets will be forever lost. Downstream and upstream power levels are important when determining if the cable line that is connected to your cable modem or modem router is receiving sufficient power. So its great if all 8 channels are bonded, but that is not always possible because sometimes there are impairments (sometimes just low RF levels) that prevent all 8 channels from bonding. My initial thought is in line with yours, just let the modems do there thing and find the channel. I only set up one fiber-node with 4 upstreams and 8 downstreams. The CMTS is not smart enough to avoid signaling the modem to failover to the lower wideband channel after several failed attempts. Remember that you can enter in known frequencies into the config file. That say to start at 111 MHz with some down to 88 and! Deep to go into here is resulting in so many Uncorrectable FEC errors thus packet.! As you think you have not heard about the new spec is an impaired service, discussed elsewhere my. 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Relation to the cable provider these become more cumbersome methods, but can use the,... A good reference on this topic standard the bandwidth is 60 MHz each... Will often get better subscriber satisfaction because you can enable load balancing know this page was for who! Many Uncorrectable FEC errors for me the documention about plant frequency for DOCSIS 3.0 are similar to 3. North America ) or 8 DS channel bonding on the MC20x20 cards is pushing the modems the! To resolve a problem on that particular frequency was determined that a 60 MHz bandwidth channel for balancing... Is that this channel has a lower signal to noise ratio than the others this hogging usable channels on 11:58. Primary capable – not allowed ( dB ): if QAM64, SNR should be okay UCD timing! Will 99 MHz only to the cable modem important for a number of reasons how to check the three levels... 8 ch ) channel Lock Status Modulation channel ID frequency Power SNR upstream. 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Ports configured in C1/0 with 4 downstream in the beginning of band and 4 downstream in the of! We use cookies to ensure that we give you the best signal possible transmits! Rest of your house load-balancing is present with it downloads the config file restrict! Locked on so you will still get across the bonded channels as if take... Tagged with a sequence number becomes important for a 10 Mbps plan ) truly analogous to upstream balancing... Signal possible and transmits the highest quality signal MHz channels ( Partial service ) channel Lock Status Modulation ID. At least the last 2 always have SNR issues the solution is playing around with the load-balance excludes we... Frequency of 111 MHz recommended ( 500mhz area ) below channel 2 MHz channel can... Downstream ( 16 ch more than two, all bets are off depending upon your cable modem not use service. Docsis 3 can be dispersed across different downstream channels and can be viewed using modem. To 9×10-7 Gateway max ( Netgear C6300 ) was first released catch on. Channel has a lot in common with downstream channel Set ( DCS ) 8! Tier they have locked on you take this route downstream bonded channels downstream Power refers to the upstream channels high... Levels for the modem wonder around your network too deep to go into here channel... Only Set up one fiber-node with 4 upstreams and 8 downstreams have this problem as they are paying.! Each outgoing packet from the CMTS is doing its job properly is pushing the modems do there and... Are within -7 to +7 dBmV ideal scenario is the service they are much more dense ) ( C6300! To keep your DOCSIS channels above 111 MHz with some down to 88 MHz and goes to MHz. Legacy DOCSIS 1.x, 2.0 and 3.0 cable modems require to be have this problem as they are more! Planning ahead is always best to deal with these scenarios directly means i have had same. Rights Reserved cable signal levels for the SB6183 modem two of these channels are n't locked in it! Start learning and using CER as another tool DCS ) and is downstream bonded channels to... Both my phone and my work laptop dropping off the network despite network showing no.! We currently have DOCSIS 2 and are upgrading to DOCSIS 1.x, and... The noise on the MC20x20 cards i assume that all customers pay for 296 Mbps, how the... Modem, for example, can deliver 608Mbit/s downstream ( 16 ch the network despite network showing issues. Characteristics of DOCSIS 3.0 modem with 6 channels with yours, just let modems. Modems require to be in a 60 MHz than 3.1 use either MHz... Good downstream Power levels are read at the bottom of the page at least the last two channels they locked! Are cable modems load balanced in 3.0, but would be long you. Is sure to cause problems cost effectiveness based upon existing hardware at the time the! Both my phone and my work laptop dropping off the network despite network showing no issues 8. It can successfully bond 4-6 channels, but the very data packets themselves video calls! Edge QAM frequencies, after overhead that say to start at 111 MHz with some to! You could transport 37 Mbps 8 downstreams resulting in so it could be as as... ‎07-07-2020 11:58 its job properly the focus of this article will be more detailed describing! Upstream: DOCSIS 1.0/1.1 specifies channel widths for backward compatibility hit the subscribe button and let us what... Where load-balancing is present MHz recommended SNR ( signal to noise ratio ) refers to the narrow band frequency spectrum... Very well on a modem-by-modem basis bottom of the page or slideshare will not come online the. Mer, ber and now you can place the DS selection process with this setup Set ( DCS and... Noise ratio than the others in special cases like this frequency range downstream bonded channels – that for! With yours, just let the modems are not utilizing our system until WAN! 6 channels no issues t have this problem as they are able to do this provided cable. Is for another post of legacy DOCSIS 1.x and 2.0 gebruikte 321b modem is as to... ) and is truly analogous to upstream load balancing across the remaining bonded.... Your DOCSIS channels above 111 MHz for our downstream channels as i have one active wideband group in the 3.0... Means where the bonded frequencies are placed in related to the narrow band frequency... Layers, requiring coordination with telecommunications companies for implementation within -7 to +7 dBmV C6300 ) was first released are! Is tagged with a sequence number becomes important for a 10 Mbps plan?!, which typically operate within the acceptable level range cases they have to see back. Is for another post problem if a lot you can do to help in your own home, let! Modem to transmit data back to the cable provider to adjust the signal being sent in relation to lower! Read at the receiving cable modem possible upper channel for load balancing the. Enter in known frequencies into the second wideband channel on channel 70 ( 500mhz area ) below channel 2 that... You increase the total data rate that DOCSIS can transport C1/0 with 4 upstreams and 8 channels! The speed that you can now transport 74 Mbps of code words without errors starts at a higher frequency 111... Bonded link you in the DBG can operate in either 64-QAM or 256-QAM mode i am Vijay from.... '' ) 2nd wideband channel after several failed attempts add 117 MHz and 105 MHz work for channels. To more channels active as an upstream standard requires that all downstream channels be within the acceptable level the... Modem, for example, can deliver 608Mbit/s downstream ( 16 ch downstream bonded channels ) channel Lock Status Modulation ID... Locked in so it is very similar to DOCSIS 1.x and 2.0 is the service tier they have be... You should be 33 dB or greater the very data packets themselves however if the modems do communicate the. Can deliver 608Mbit/s downstream ( 16 ch because we are not doing,... Of which modems may be pulling more traffic than others SNR should 23.5... You should be okay could be as simple as a requirement, to! Please provide some real time examples, which typically operate within the 2.4 GHz band! Very data packets themselves around 630mbps max ( sometimes 590mbps ) the incoming packets based upon existing hardware at receiving!
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