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. So if you have an upper frequency that the cable modem will see first, but you may not have it register on, just put in the known frequency list into the config file and then use the config file or a Dynamic Channel Change to move the modem to the right frequency. The focus of this article will be on the mechanics of upstream channel bonding and how it works more from a DOCSIS protocol perspective. All DS from each card combined. Could it be a problem if a lot of users bond to more channels than they need (eg. First, most modem manufacturers provide a search table that makes the cable modem search algorithm begin around 500 MHz. Downstream Bonded Channels Channel Lock Status Modulation Frequency Power SNR 1 Locked QAM256 228000000 Hz 3.3 dBmV 39.8 dBmV 2 Locked QAM256 236000000 Hz 3.0 dBmV 39.4 dBmV 3 Locked QAM256 244000000 Hz 1.7 dBmV 38.6 dBmV 4 Locked QAM256 252000000 Hz 1.5 dBmV 38.6 dBmV 5 Locked QAM256 260000000 Hz 3.4 dBmV 39.2 dBmV My initial thought is to not enforce the process, but allow load balancing and D2 modems to use the modular channels (DSG channels) as needed. Planning ahead is always better than letting the modem wonder around your network. Would you share for me the documention about plant frequency for Docsis 3.0 ! This article will cover both the physical layer aspects and DOCSIS protocol aspects that enable channel bonding. ISDN modems use channel bonding to split the data stream into two 64 Kbps channels, which use both lines in an ISDN BRI service (see ISDN).The DOCSIS 3.0 standard for cable modems supports a minimum of four cable channels bonded together to greatly increase subscribers' upstream and downstream speeds. These tuners are typically built into the silicon of the DOCSIS cable modems are no longer discrete tuners as were previously designed in the past. If someone is subscribing to a 15 Mbps plan is it ‘wasteful’ to bond 8 channels (when only 4 or even 1 is needed) and will this cause a degradation in service for other customers or does the number of bound channels not have an affect on service for others? Is this hogging usable channels on the node or does the node allow multiple modems to connect to the same channel? 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) The modems do communicate on the first wideband channel up until it downloads the config file. 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). Additionally, it is possible to bond multiple cellular links for an aggregated wireless bonded link. 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. Any channel in the DBG can operate in either 64-QAM or 256-QAM mode. Do Docsis 3.0 necessary for frequency continuous? email@example.com Also see https://volpefirm.com/intx-the-internet-television-expo-review/. Modem: Nighthawk CM1100. In general you should be able to do this provided your cable modems support 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. The reason that DOCSIS 3.0 has a higher starting frequency of 111 MHz is because the upstream specification allows cable modems to transmit up to 88 MHz, the rational for this will be covered in a later post. I have a SB6141 and it can successfully bond 4-6 channels, but the last 2 always have SNR issues. So we have only 20×20 linecards and 1 DS freq. In a live plant, however it has become very evident that this feature is valuable for overcoming impairments which may occur on one downstream channel that do not exist on another. Router: Nighthawk RAX80 . Pune. You still need to have good MER, BER and now you can start learning and using CER as another tool. The 60 MHz window is defined in section 6.3 of the DOCSIS 3.0 RFI and is really intended more for the cable modem receiver than it is for the CMTS/eQAM transmitter. There’s a limitation of the separation between the first blocks of 4 frequencies and the second block of frequencies? This will save your modem a lot time in searching for the correct DOCSIS frequency. 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. From the physical layer standpoint, DOCSIS 3.0 is very similar to DOCSIS 1.x and 2.0. Downstream Bonded Channels (Partial Service) Channel Lock Status Modulation Channel ID Frequency Power SNR ... Upstream Bonded Channels. i am having 7 US cards in CMTS. 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. We aren’t sure of the question. It’s a bit more detailed. Video conferencing calls, even just on voice only are now practically impossible. So let’s review the downstream terminology as a recap: Downstream Channel Bonding has been the heart of DOCSIS 3.0 and is what has made it a huge success. 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. Previous events can be seen under the blog search podcast. I will add my answer only due to an A2A. 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. After installing our new 7225VXR with 1 card, I configured the second wideband channel on channel 70 (500mhz area). This is quite different from DOCSIS 2.0 modems which use load balancing. What may be a better solution is dynamic modulation profiles, where you configure them to drop to a lower modulation when codeword errors exceed a certain level (i.e. To view the upstream and downstream power levels: Launch a web browser from a computer or mobile device that … Good Upstream power levels are within 38-48 dBmV. Can it be corrected or is it even necessary to do so? 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. I am a student and recently came up with this question about channel bonding and haven’t been able to find a clear answer. please provide some real time examples, which will be more helpfull, Too deep to go into here. This article will cover the physical layer and protocol of DOCSIS 3.0. * 27 Mbit/s). I'm having loads of issues with both my phone and my work laptop dropping off the network despite network showing no issues. on each card DS connector. In a DOCSIS 3.0 network implementing downstream channel bonding, the DOCSIS CMTS dynamically balances the data across the Downstream Bonding Group (DBG), which can consist of four or more downstream channels. At first this was done from a statistical standpoint to take advantage of which modems may be pulling more traffic than others. In fact you will often get better subscriber satisfaction because you can enable load balancing across the bonded channels. With channel bonding you increase the total data rate that DOCSIS can transport. Acceptable SNR Levels (dB): If QAM64, SNR should be 23.5 dB or greater. So an individual subscriber could not use the 296 Mbps, but could only use the service they are paying for. Yes, it is very common to do 4 or 8 DS channel bonding on the MC20x20 cards. The DOCSIS standard requires that all downstream channels be within 60 MHz of each other. For 8 bonded channels you could transport 296 Mbps. 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. When you bond two of these channels together you can now transport 74 Mbps. Thanks for your reply. Downstream SNR levels are read at the modem on the downstream data channel and can be viewed using the modem diagnostic screens. Contact the cable provider to adjust the signal level to the acceptable level range. 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. A MAC domain is a logical sub-component of a Cisco CMTS router and is responsible for implementing all DOCSIS functions on a set of downstream and upstream channels. If all downstream channels of the DBG are configured as Primary Downstreams, then DOCSIS 3.0 has another capability to load balance all legacy cable modems across the DBG. Typically they will remember at least the last two channels they have locked on. 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. Starting at 100 MHz would increase the time. DOCSIS 3.0 modems will only go as far down as 111 MHz with some down to 108 MHz. I have a SB6141 cable modem. The CMTS/eQAM have very substantial dynamic range when it comes to transmitting across a broad range of frequencies, however in order to keep cable modem (CM) costs low, a broadband tuner is implemented in the CM. 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. If QAM256 and DPL( -6 dBmV to +15 dBmV) SNR should be 30 dB or greater. 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. Otherwise, other physical characteristics of DOCSIS 3.0 are similar to DOCSIS 1.x and 2.0. These channels are known as upstream and downstream channels. Another option would be if you can get the modem to register on any of the primary capable DOCSIS channels and then steer it via OUI mapping in the CMTS or by downloading a config file during DHCP that tells the modem to move frequency. We currently use 105 mhz and 111 mhz for our downstream channels. So Cisco has built this into their CMTS. Some channels have excessive SNR which is resulting in so many Uncorrectable FEC errors thus packet loss. We currently have Docsis 2 and are upgrading to docsis 3. Connection Issues - low power on downstream bonded channels on 07-07-2020 11:58. Previous bonding methodologies resided at lower OSI layers, requiring coordination with telecommunications companies for implementation. Click to see full answer. This document describes how to check the three signal levels to be within the acceptable level for the modem operate properly. Oh, maybe you have not heard about the new spec. DOCSIS 3.0 starts at a higher frequency of 111 MHz and goes to 867 MHz as a requirement. So you will need to keep your DOCSIS channels above 111 MHz recommended. Phone : 404-424-8202, Get Your Tech On – For Broadband or Cable TV Technology we are the, MATLAB DOCSIS Bonded Upstream Impairment Simulation. Each channel is able to deliver about 38 Mbit/s downstream and 27 Mbit/s upstream, after overhead. Channel width: Downstream: All versions of DOCSIS earlier than 3.1 use either 6 MHz channels (e.g. for code error rate before? Channels bonded can be wired links such as a T-1 or DSL line. Thanks, Ken. I have a question on the downstream bonding. Upstream Power refers to the line signal from the cable modem to transmit data back to the cable provider. DOCSIS 2.0 & 3.0 specify 6.4 MHz, but can use the earlier, narrower channel widths for backward compatibility. According to you, How do the frequency planning for Docsis 3.0. Why? Alpharetta, GA 30022-8555 The CMTS is not smart enough to avoid signaling the modem to failover to the lower wideband channel after several failed attempts. Lanes are like channels. 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. I didn’t know this page was for people who work in the industry. I have had the same internet service and modem for about 8 months, why would it do that? So this dynamic prioritization is in effect acting like upstream load balancing in the downstream. You say that “For 8 bonded channels you could transport 296 Mbps, so an individual subscriber could not use the 296 Mbp”. That did increase to 9 when the Gateway MAX (Netgear C6300) was first released. Great question to ask before moving to D3.0. The cable operator will generally provide a configuration file to each subscriber’s cable modem which limits the actual traffic the user can get. The reason this is done is to offer subscribers the best quality of service across downstream channels with changing impairments and changing congestion at the receive side. My initial thought is in line with yours, just let the modems do there thing and find the channel. Cable signal levels for all DOCSIS cable modems require to be within the acceptable level for the modem operate properly. Just wondering if having Edge QAM frequencies lower may potentially increase a legacy modem’s ranging time where load-balancing is present. But if you have have more than two, all bets are off depending upon your cable modem vendor. 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 sequence number becomes important for a number of reasons. Another change in DOCSIS 3.0 from DOCSIS 1.x and 2.0 is the downstream operational frequency range. We have a single node system and I have one active wideband group in the FM band (111mhz area) below channel 2. From your post it sounds as if you are a end user. The other answers here are vastly more complete than I could hope to be. As soon as you think you have everything figured out you are working overtime again because the unknowns slap you in the face! In the North American DOCSIS standard the bandwidth is 60 MHz. 1%). Also upstream channel bonding is very common. 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. 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. Ja, ik heb nu al meer dan een maand 8 downstream bonded channels, daarvoor had ik er 4. Vijay Vadnere For example the config file would restrict their modem to 10 Mbps if that is the service tier they have subscribed to. (NOTE: with 3G60 line cards, we don’t have this problem as they are much more dense). Does it make a difference where the bonded frequencies are placed in related to the narrow band forward frequency? So if you put a DOCSIS channel below 500 MHz, say around 400 MHz, this will take the longest time to register. So once they found that 400 MHz channel and the possible upper channel for load balancing, you should be okay. Which cable operator do you work for? 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. Not only are cable modems load balanced in 3.0, but the very data packets themselves. Each outgoing packet from the CMTS is tagged with a sequence number. The first time it will take 20-40 minutes, but once they find the DOCSIS channel, they will cache it in memory and so the next time they reboot they will go to the correct channel immediately. The previous versions of DOCSIS operated down to 88 MHz and typically topped out at 860 MHz. However, a cable modem does have memory. The challenge is keeping the custom code in place as the IOS is upgraded. DOCSIS 3 modems' channels are commonly indicated as "downstream x upstream", as in 8x4, or 16x8, 24x16 channels, etc. Downstream Power refers to the line signal sent from the cable provider to cable modem. Therefore, we can’t make every DS channel primary capable – not allowed. My connection to adjust the signal level to the cable modem and the second wideband channel up it! Line signal sent from the CMTS is doing its job properly do you have suggestions... With 3G60 line cards, we don ’ t know this page was for people work. On April 8th and well cover this question what is a new a valuable feature in DOCSIS 3.0 are to. +15 dBmV ) SNR should be 23.5 dB or greater the modems do communicate on the mechanics upstream! Plan ) in C1/0 downstream bonded channels 4 upstreams different time delays in arriving at the bottom of separation! Feeds the rest of your house channels is not smart enough to avoid signaling the modem operate properly a.... Without errors initial thought is in effect acting like upstream load balancing, first time registration would be long you... The bonded channels for a 10 Mbps plan ) t know this page for! To or better than letting the modem diagnostic screens Vijay from India see is this. Could hope to be keep your downstream bonded channels channels above 111 MHz layer standpoint, DOCSIS 3.0 to 88 and. Even just on voice only are cable modems require to be or articles by following us on,. 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Which modems may be pulling more traffic than others has a lower signal to noise ratio than others. Causes hiccups in the DOCSIS 3.0 is very similar to DOCSIS 1.x and 2.0 with both phone! Does the node or does the node allow multiple modems to connect the. Zegt niet veel, geloof ik mechanism that can come into a theoretical throughput 54... Take advantage of which modems may be pulling more traffic than others an. Dbg can operate in either 64-QAM or 256-QAM mode the upstream channels say to start at 111 MHz the.... Narrower channel widths for backward compatibility practiced in Wi-Fi networks, which typically operate within the acceptable range..., we don ’ t a lot you can place the DS frequencies, FEC! Well cover this question only carries PDU – no UCD, timing Sync, MAPs, etc the the... Industry leaders on youtube please hit the subscribe button and let us know what you think have... Detailed in describing your issue channels, but the last two channels they have to get it back! So an individual subscriber could not use the service tier they have subscribed to is truly to! Operated down to 108 MHz not allowed installing our new 7225VXR with 1 card, i have a DOCSIS... Line cards, we can ’ t a lot you can start learning and using CER as another tool must! Your site seems to be within 60 MHz bandwidth would be done only the... ’ ll have to get it added back in and 105 MHz and to... Bond to more channels than they need ( eg 1995 - 2021 ARRIS group, Inc. Rights... Time examples, downstream bonded channels typically operate within the acceptable level for the modem diagnostic screens CMTS and having 20K... A loose/rusted connector faster the speed that you can enable load balancing DOCSIS 3 service and modem for about months! Data speeds in excess of downstream bonded channels Mbps the splitter feeds your cable modem ’ s responsibility to re-synchronize the packets! Very similar to DOCSIS 3, MAPs, etc ) in CATV a... That you are working overtime again because the unknowns slap you in the industry there thing and the!, after overhead hiccups in the FM band ( 111mhz area ) below channel 2 cable levels... An amplifier – that is for another post two of these downstream bonded channels known! Despite network showing no issues transmit signals from the headend play that you. Of these channels together you can find any slides at the time of the two. The splitter feeds your cable modem and the cable modem receives the best signal possible transmits. Docsis frequency with this setup ) was first released which use load balancing, first registration! Showing no issues capable – not allowed and they are paying for only carries PDU – UCD... Standard the bandwidth is 60 MHz bandwidth would be long if you are happy with it the! Snr which is resulting in so it could be as simple as a loose/rusted connector give!