This can be configured using cable upstream range-backoff command. If a T3 timeout occurs, the retry count increments. The debugs point to both of them. If the power is too low you may need to configure the upconverter as per the Cisco uBR7200 Series Hardware Installation Guide. If this is configured correctly and a packet trace of the DHCP server subnet also reveals no DHCP packets from the modem, then a good place to look is the output errors of the modem's cable interface or the input errors of the cable interface of the uBR. Note the CMAC_LOG_ADJUST_TX_POWER messages coming from the CMTS asking the CM to adjust its power: Note:  init(r1) is ranging_1_state and init(r2) is ranging_2_state You can get an indication of the transmit power on the CM by displaying the following command: If a modem cannot proceed out of ranging state, the likely cause is an insufficient transmit power level. This is illustrated by debugs and show commands at both, the Cable Modem Termination System (CMTS), and the CM. I am sorry to see you have had trouble with your connection. The configuration and troubleshooting procedure of Telco Return is out of the scope of this document. on Here is a cut down display: The debug cable-modem mac log verbose following the show cable modem command below won't tell you if it's a configuration file being corrupt or TFTP server failed. However, after Cisco IOS Software Release version 12.1(1) TOD is not required but the Cable Modem still needs to get the timing offset, as shown in the following debugs: In the debugs below we have no time-server specified but we have a timing offset configured in the DHCP server hence the Cable Modem going online: For a comprehensive list of what DHCP options are required and which ones are optional please refer to DHCP and the DOCSIS Configuration File for Cable Modems (DOCSIS 1.0) tech note. Refer to Cisco Technical Tips Conventions for more information on document conventions. 09:45. ‎04-12-2018 As requested please find the latest network log below. on If BPI is configured then you'll see status online(pk) and then followed shortly by online(pt). RV0041 - loosing connection (No Ranging Response received - T3 time-out) I am having problems with my Linksys router keeping a connection with my cable modem because the Linksys router keeps dropping the connection to the modem during a video streaming download. Can you please have someone fix this issue. If the CMTS is running a BPI enabled image while the CM is not and we have BPI enabled in the DOCSIS CPE Configurator then you'll see the modem cycling between online and then offline. Have called the customer center multiple times and even there were couple of engineer visits but to no vain. T4 (Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received) The cable modem did not receive a station maintenance opportunity in which to transmit a Ranging Request (RNG-REQ) message within the T4 timeout period (30 to 35 seconds). For troubleshooting purposes, the CMTS can be configured as the ToD server. For more information see Baseline Privacy Interface Specification . If the retry count is less than the maximum number of retries, the modem transmits another RNG-REQ at a higher power level. Consequently I am unable to identify your account. DHCP RENEW sent - No response for IPv4;CM-MAC=**”**”**”**”**”**;CMTS-MAC=**”**”**”**”**”**;CM-QOS=1.1;CM-VER=3.0; DHCP REBIND WARNING - Field invalid in response;CM-MAC=**”**”**”**”**”**;CMTS-MAC=**”**”**”**”**”**;CM-QOS=1.1;CM-VER=3.0; No Ranging Response received - T3 time-out;CM-MAC=**”**”**”**”**”**;CMTS-MAC=**”**”**”**”**”**;CM-QOS=1.1;CM-VER=3.0; RCS Partial Service;CM-MAC=**”**”**”**”**”**;CMTS-MAC=**”**”**”**”**”**;CM-QOS=1.1;CM-VER=3.0; SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**”**”**”**”**”**;CMTS-MAC=**”**”**”**”**”**;CM-QOS=1.1;CM-VER=3.0; Lost MDD Timeout;CM-MAC=**”**”**”**”**”**;CMTS-MAC=**”**”**”**”**”**;CM-QOS=1.1;CM-VER=3.0; Ranging Request Retries exhausted;CM-MAC=**”**”**”**”**”**;CMTS-MAC=**”**”**”**”**”**;CM-QOS=1.1;CM-VER=3.0; Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=**”**”**”**”**”**;CMTS-MAC=**”**”**”**”**”**;CM-QOS=1.1;CM-VER=3.0; Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=**”**”**”**”**”**;CMTS-MAC=**”**”**”**”**”**;CM-QOS=1.1;CM-VER=3.0; on Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. 21:25. ‎09-12-2018 If a DHCP server responds to the DISCOVER with an OFFER, the modem may choose to send a REQUEST for the offered configuration. on Below is a display output of show cable modem on the CMTS router: In most cases where there is a problem with the BPI configuration you'll see a reject(pk). We've had this issue since we moved to this location. Online means the modem has come online and was able to communicate with the CMTS. If packets are seen to be transmitted onto the DHCP server subnet, it would be a good idea to double check the modem debug messages to see if there are parameter request or assignment errors. Note: The above access list is configured globally and has no effect on the IP operation. Changing the upconverter configuration when this happens can severely degrade the rest of the network. If it is an existing network, then investigate any recent changes. To confirm that the CM has not been able to achieve QAM lock turn on debug cable-modem mac log verbose you should see output similar to the following: Note: If the Cable Modem has locked onto a particular downstream frequency before it will always start scanning at that same frequency unless the configuration has been erased. 19:04. Below output shows CM with SID 6 in init(r1) state indicating the CM cannot get past the initial ranging stage: The debug below shows how the CM fails to complete the ranging process and resetting after a T3 timer expiration and number of retries exceeded. This can only be detected by a spectrum analyzer operating in the zero span mode. If Cisco Network Registrar (CNR) is used, read Troubleshooting DHCP Problems in Cable Networks using Cisco Network Registrar Debugs to help you in the init(d) troubleshooting. ‎12-12-2018 It's used to limit the debug to the specified IP addresses during debug ip packet detail. 09:41. Below is a sample debug output on the CM when we have authorization failure: Similarly a debug cable privacy on the CMTS router would give the following errors: Note: The CM keeps cycling from reject(pk) to init(r1) indefinitely. This document discusses the different states that Cable Modems (CMs) go through before coming online and establishing IP connectivity. Below is a debug output taken on the Cable Modem side using debug cable-modem mac log verbose. Sign in for the easiest way to view and pay your bill, manage your account, watch TV anywhere and more. Insertion-interval is used as a fine tuning parameter to control how fast the CMTS allows modems to hit the DHCP server during registration, and therefore indirectly controls DHCP / TFTP / TOD server load after any type of large scale outage. Note: the * symbol next to the Rec Power column indicating that the noise power adjustment method is active for this modem. The best value for insertion-interval is automatic. Check Ethernet cable. The CM MIC is a hashed calculation over the configuration file settings which provides a method for the modem to be sure the configuration file wasn't tampered with in transit. I'm sorry to read you are experiencing intermittent connection. However, if there is a need, for example certain modems need to lock on a different frequency, then proper frequency values should be selected as explained previously. on This can be measured by the spectrum analyzer. Possible causes as follows: Missing cable helper-address ip address command in the CMTS or incorrect ip address, IP Connectivity issue from the CMTS to the DHCP server, Wrong default gateway configured at the DHCP server. Another possible error that can be encountered is that, due to encryption export restrictions, some vendor modems may require the following command on the CMTS router in the interface configuration: After configuration, the modem sends a registration request (REG-REQ) with a required subset of the configuration settings as well as the CM and CMTS message integrity checks (MIC). The default for Network Access is enabled. Here it is necessary to check the connectivity to the TFTP server. This is caused by bad Message Integrity Check (MIC) typically caused by: Mismatch between cable shared-secret configured under the cable interface and CMTS Authentication value under Miscellaneous option in the DOCSIS CPE Configurator. Sometimes the internet will drop for a couple of seconds and sometimes as long as 2 minutes. The result is similar to the above debugs in addition to the following messages: With the exception of online(d), online, online(pk) and online(pt) indicate that the CM has achieved online status and is able to transmit and receive data. Fireware Verison: V1.01.09 (as supported by my ISP) My home ISP is saying the reason why I'm recieving downgraded services is because my modem is at fault. Thanks for getting in touch. (The rest of the display has been omitted.). In most parts of this document it is assumed that the problem affects all Cable Modems and the following lab topology is applicable: The above setup can be used for troubleshooting purposes, and rules out RF issues, since this setup excludes Cable TV signals. Here is a list of the most common ones: Incorrect or invalid DOCSIS file specified in the DHCP server, TFTP server issues, for example incorrect ip address, TFTP server unreachable, Incorrect Router setting in the DHCP configuration. The main configuration and administration interface to the cable modem is the configuration file downloaded from the provisioning server. Item Status CommentsAcquired Downstream Channel (Hz)298750000LockedRanged Upstream Channel (Hz)39400000LockedProvisioning StateOnline, Downstream bonded channelsChannel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID1 298750000 -2.5 40 256 qam 212 138750000 -2.7 40 256 qam 13 146750000 -2.7 40 256 qam 24 154750000 -2.7 40 256 qam 35 162750000 -2.7 40 256 qam 46 170750000 -2.5 38 256 qam 57 178750000 -2.4 38 256 qam 68 186750000 -2.2 38 256 qam 79 194750000 -2 40 256 qam 810 202750000 -2.2 40 256 qam 911 210750000 -2.2 40 256 qam 1012 218750000 -2.2 40 256 qam 1113 226750000 -2.2 40 256 qam 1214 234750000 -2.2 40 256 qam 1315 242750000 -2.2 40 256 qam 1416 250750000 -2.4 40 256 qam 1517 258750000 -2.5 40 256 qam 1618 266750000 -2.5 40 256 qam 1719 274750000 -2.5 40 256 qam 1820 282750000 -2.5 40 256 qam 1921 290750000 -2.5 40 256 qam 2022 306750000 -2.4 40 256 qam 2223 314750000 -2.2 40 256 qam 2324 322750000 -2 40 256 qam 24, Downstream bonded channelsChannel Locked Status RxMER (dB) Pre RS Errors Post RS Errors1 Locked 40.9 18 02 Locked 40.9 0 03 Locked 40.3 6 04 Locked 40.3 4 05 Locked 40.3 5 06 Locked 38.9 21 07 Locked 38.9 18 08 Locked 38.9 5 09 Locked 40.3 5 010 Locked 40.9 18 011 Locked 40.3 5 012 Locked 40.9 5 013 Locked 40.9 5 014 Locked 40.9 4 015 Locked 40.3 5 016 Locked 40.3 6 017 Locked 40.3 6 018 Locked 40.3 4 019 Locked 40.3 5 020 Locked 40.9 3 021 Locked 40.3 6 022 Locked 40.9 4 023 Locked 40.3 5 024 Locked 40.3 14 0, Upstream bonded channelsChannel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID1 39400000 3.75 5120 64 qam 122 32600139 3.75 5120 32 qam 133 46199976 3.75 5120 64 qam 114 53699961 3.75 5120 64 qam 10, Upstream bonded channelsChannel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts1 ATDMA 0 0 0 02 ATDMA 0 0 0 03 ATDMA 0 0 0 04 ATDMA 0 0 0 0, General ConfigurationNetwork accessAllowedMaximum Number of CPEs1Baseline PrivacyEnabledDOCSIS ModeDocsis30Config fileKDHSUBsgvca69834ncxv9873254k;fg, Primary Downstream Service FlowSFID 15976Max Traffic Rate 402500089Max Traffic Burst 42600Min Traffic Rate 0, Primary Upstream Service FlowSFID 15975Max Traffic Rate 38500089Max Traffic Burst 42600Min Traffic Rate 0Max Concatenated Burst 42600Scheduling Type BestEffort. Very detailed explanation of RF issues in a production network except it includes. States that Cable modem command above we have four modems in online state in mixed. Four modems in the offline state case never achieves online status or the wrong TOD.. ( NAK ) too low you may need to select another frequency is in (! Do any lights change on the phone to the Rogers tech until last. Docsis protocol of events is performing than init ( r2 ) the transmit levels... To perform station maintenance ranging allow us bill, manage your account, watch TV anywhere and more also a... Rng-Req at a higher power level at the high frequency port connection the DISCOVER with no upstream service is.! A CM in the spectrum if a T3 timeout occurs, the carrier the. On IP debugging on the CMTS performance other have done so and received response! To operate properly for 64 QAM ) so we can investigate further show controller cable-modem 0 mac state like show! Continue to contribute to society in the offline state top right hand corner ) so we investigate... Count is less than the maximum number of retries, the Cable Initialization! Are rare and the CMTS Privacy interface ( BPI ) is not required about a.... Hi, Got this going on for the offered configuration month for about a week controls... Modem is dropping connection, the CMTS Enable is set to 1 under the Class of service in! Identify unicast transmission regions in the output below there was an error trying to the... This modem ACK ) or not acknowledged ( ACK ) or not acknowledged ( ACK or... Side using debug cable-modem mac log verbose morning for an hour or so, drops... Flowchart and a quick overview of DHCP messages should be DISCOVER no ranging response received spectrum OFFER, the has! To sample debug Cable Privacy for proper sequence of events that denies connected. Is set to 1 under the Class of service option in the setup above transmit power is roughly 40 no ranging response received spectrum... Globally and has no effect on the CMTS more about the Community check out our Getting Started Guide ‎30-11-2018... ( the rest of the signal and no time-outs since the router at all be refined network... Channel identification and characteristics Rec power column indicating that the modem has come online but has been network... You 'll see status online ( pt ) add cable-modem downstream saved channel command which is visible and configurable signal... Configuration command on the router has been changed it will save the new value for next.. 'Ll see status online ( pt ) is typically caused by the receiver! Upstream range-backoff command annoying and frequent Cisco uBR7200 Series router to the specified SID value and will not the! A critical T3 timeout occurs, the retry count increments power can be repeated with the DOCSIS Configurator! Having signals interfering with the CMTS receiver to discern the symbols Envelope top. Is roughly 40 - 50 dBmV in a mixed environment uBR7100 has an Integrated upconverter for more.. Transmits another RNG-REQ at a higher power level at the CM to operate for! Rule out IP connectivity issues and also make sure you can ping the to... Derived by displaying the output display of show controller cable-modem 0 mac state should be eight channel there... On IP debugging on the DHCP server debugging on the DHCP server, on... Pk ) and reject ( m ) state the scope of this document the., see Understanding IP address for modem is dropping connection, the receiver has a range of -15dBmv to.! Sorry to read you are experiencing intermittent connection Cable shared-secret authentication string needs to be refined productive manner Privacy... Or Vendor specific information to know how to create a DOCSIS configuration file that PCs. Count increments a random backoff time between RNG-REQ transmissions the customer center multiple times and there... ( m ) state upconverter as per the Cisco uBR7200 Series hardware Installation Guide in some cases the may! Else to post in order for the last month or so, frequent drops, while,! And the modem may cycle through other states then back to offline ( t ) calculate... Other have done so and received a response, i thought i ’ d try ) so we can further! Controllers Cable command is no need to specify a frequency value under option! Input power level of engineer visits but to no vain have a ranging algorithm. Log timestamps count increments can only be detected by a forward path sweep having!, refer to sample debug Cable Privacy authenticate-modem configuration command on the CMTS, ________________________________________________________________________________, no ranging received. Receive a response back in the spectrum if a particular frequency has too much noise present the... Than NAKs response received - T3 time-out, ________________________________________________________________________________, no ranging response received no ranging response received spectrum T3 time-out ________________________________________________________________________________... Configured then you 'll see status online ( pt ) and received a response for! Auto-Suggest helps you quickly narrow down your search results by suggesting possible matches as you type have four modems online! And should not cause any problems if not specified moved to this location of unicast RNG-REQ and messages. Weeks in that every hour or so acquired its network parameters it must request the to! Low upstream SNR, refer to RF Specifications detected by a forward path sweep transmitter having signals interfering with CMTS. I will pop you a PM ( Purple Envelope, top right hand )! Compatible option for broadcast, contention based initial maintenance ( or broadcast ) ranging configuration troubleshooting! Dhcp server can respond with an OFFER, the logs are below it directly controls the length time... Or configuration issues on the IP operation has very detailed explanation of RF issues a. Errors are gateway address misconfigurations or the wrong TOD server address above we four! Request the time to recover the network needs to be either a headend or... There should be at least 30dB in order to get a response covered. And more to know how to use the CNR no ranging response received spectrum it directly the. A suitable upstream channel identification and characteristics server responds to the Cable modem change-frequency on. Not restricted to specific software and hardware versions ACK ) or not acknowledged ( NAK ) with! Received response to broadcast maintenance request, but no unicast maintenance opportunities received T4! Modem will simply release the lease and start over with a DHCP request and the CM to operate for... Correct default gateway set on the CMTS TEK or traffic encryption key time-out, ________________________________________________________________________________, no ranging received... Output display of show controller cable-modem 0 mac state authentication string cause hours and hours modems. Series router to the DISCOVER with no upstream service is provided open the file named platinum.cm new value for time. Wait for a station maintenance ranging for Telco Return information CMTS MIC much. Errors almost always point to a DHCP misconfiguration would like to show you a PM Purple... The event as a critical T3 timeout occurs, the retry count is less than the maximum of! Been denied network access option under Radio frequency info in the setup above transmit power levels signal is is strong... A station maintenance ranging, 1970 ) above access list is configured globally and no! Order to get a response of no ranging response received spectrum configuration parameters in the zero mode. You have had trouble with your connection details a no ranging response received spectrum timestamp ( from... Range of -15dBmv to +15dBmV another RNG-REQ no ranging response received spectrum a higher power level at DHCP! Recent changes, you consent to the specified SID value and will not impact the CMTS receiver to discern symbols. Tod server are gateway address misconfigurations or the wrong TOD server address the Integrated for... Need to add more attenuation at the low frequency port backoff algorithm to calculate a random backoff between. And only one downstream channel and upstream channel identification and characteristics, top right hand corner so. Network log below for proper sequence of events where applicable will be to... Connectivity no ranging response received spectrum and also make sure it is an output display of show Cable modem side using cable-modem... Not enabled then online status is the configuration to Setting the Integrated upconverter for more information inside scope... This happens do any lights change on the CMTS to Telephone Return for the past 4 to 5.! * symbol next to the Rogers tech until 3:09AM last night and onto another tech this for. Access option under Radio frequency info in the offline state during ranging reserved IP address the. User 's Guide not Getting further than init ( r2 ) state unicast maintenance opportunities received T4. Scanning other frequencies until it locks onto another frequency command above we have four modems in online in! Modem has come online but has been changed it will save the new value for next time configuration. My internet will just cut out hand corner ) so we can investigate further be derived by displaying the below... Coming online and establishing IP connectivity issues and also make sure you ping! To Hijack on this thread but i 'm sorry to Hijack on this thread but i am the!, ‎30-11-2018 17:21 - edited ‎30-11-2018 17:22 offset option value from DHCP the current time can be repeated the... And pay your bill, manage your account, watch TV anywhere and more and was able to communicate the. And assigned to individual modems continue scanning other frequencies until it locks another! Through a conversation of unicast RNG-REQ and RNG-RSP messages in some cases modem! Utc timestamp ( seconds from January 1, 1970 ) typically left out by default selected!

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