no ranging response received spectrum

Other hardware may vary. A section of time is mapped out into mini-slots and assigned to individual modems. The best value for insertion-interval is automatic. on on It is these regions of the MAP that the modem must send its initial ranging requests until the CMTS responds with a ranging response (RNG-RSP). In some cases you may have a good Signal to Noise Ratio (SNR) of say 34dB but still have noise present such as impulse noise. The modem continues to transmit RNG-REQ and perform adjustments per RNG-RSP until the RNG-RSP message indicates ranging success or ranging complete by reaching the init(rc) state. You can also use debug ip udp if this is a test or lab router: Caution: Running debug ip udp command on a Universal Broadband Router (uBR) cannot be used in conjunction with an access list because this may cause the uBR to halt the system in order to keep up with the debugging. 2. The configuration and troubleshooting procedure of Telco Return is out of the scope of this document. Typically this is caused by: CMTS router is unable or unwilling to grant a particular requested COS. Misconfigured parameter(s) in Class of Service option in DOCSIS CPE Configurator, for example having two classes of service with the same ID. 14:02. This document discusses the different states that Cable Modems (CMs) go through before coming online and establishing IP connectivity. This state is typically caused by the following: Corrupt public key by the CM in the auth request. 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. Thanks for getting in touch. To compensate for this the modems have a ranging backoff algorithm to calculate a random backoff time between RNG-REQ transmissions. 19:10. on 16:00. From checking your line, everything has come back as fine. Roughly 20 - 30 dB of attenuation is a good place to start. 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). A NAK may be a result of an incompatible IP address and gateway address as might occur if a modem hopped from one downstream channel to another which resides on a different subnet. 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. This configuration file contains: Downstream channel and upstream channel identification and characteristics. Refer to sample debug cable privacy for proper sequence of events. Network LogTime Priority Description17/08/2019 06:29:57 critical 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;17/08/2019 07:40:24 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;17/08/2019 07:42:40 critical 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;18/08/2019 09:13:25 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;18/08/2019 09:16:47 critical 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;18/08/2019 10:20:44 critical Unicast Ranging Received Abort Response - initializing MAC;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;18/08/2019 10:20:44 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;18/08/2019 10:23:8 critical 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;18/08/2019 10:23:48 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;18/08/2019 10:24:36 critical 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;18/08/2019 10:25:6 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;18/08/2019 10:25:53 critical 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;18/08/2019 10:26:55 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;18/08/2019 10:28:6 critical 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;18/08/2019 10:28:36 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;18/08/2019 10:29:3 critical Unicast Ranging Received Abort Response - initializing MAC;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;18/08/2019 10:29:3 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;18/08/2019 10:29:51 Warning! TOD uses a UTC timestamp (seconds from January 1, 1970). Note: Before starting to troubleshoot any state it is important to look at the state of all the Cable Modems to see whether or not this state applies to all the modems or just a few, and whether this is a new or existing network. The recommended value is 1600 or 1800 bytes. This website uses cookies. An example of invalid Configuration Parameters in the DOCSIS CPE Configurator is invalid or missing Vendor ID or Vendor Specific Information. See CMTS Sample Config. There are also regions in the MAP for broadcast, contention based initial maintenance (or broadcast) ranging. Refer to RF Specifications for Data Over Cable Service Interface Specification (DOCSIS) Downstream and Upstream specifications, and also About Verifying the Downstream Signal. I will pop you a PM (Purple Envelope, top right hand corner) so we can investigate further. To find out more about the Community check out our Getting Started guide, ‎30-11-2018 Once locked, it will save the new value for next time. To learn why the GI upconverters use this frequency read Cable Radio Frequency (RF) FAQ (registered customers only) . Sign in for the easiest way to view and pay your bill, manage your account, watch TV anywhere and more. 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). This would be the stage of troubleshooting where one should investigate the routing between the modem and the DHCP server. ‎12-12-2018 This can be done with the following steps: Once a reply to the DHCP request has been received and an IP address assigned to the Cable Modem the next the show cable modem gives is init(i): From the above the Cable Modem with SID 7 never gets beyond state init(i). The default for Network Access is enabled. Received Response to Broadcast Maintenance Request, but no unicast maintenance opportunities received – T4 timeout . T4 Timeout ( 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). In some cases the modem may cycle through other states then back to offline. After going back and forth with Arris and xFinity, both sides would just blame each other for "bad service levels" or "bad modem". ‎04-12-2018 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. The CM sends a DHCP request and the CMTS relays those DHCP packets in both directions. ToD request sent - No Response received;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;18/08/2019 10:30:11 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;18/08/2019 10:31:9 notice Received REG-RSP while in REG-HOLD1 state;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0; on The time to wait for a REG-RSP during registration. It's used to limit the debug to the specified IP addresses during debug ip packet detail. This document also discusses some of steps that can be taken to arrive at the correct status, which include the several online statuses like online(pt) or online(d). It's also worth noting that the configuration command cable downstream frequency on the CMTS is cosmetic only and has no effect on the upconverter output frequency exept in the case of the uBR7100, which has an integrated upconverter. However, the upconverter GI C6U or C8U uses 1.75MHz below the center frequency then you need to set the frequency for 649.25 MHz for Channel 100-100. This is likely to be a headend misconfiguration. ‎12-12-2018 T4 Timeout (Received Response to Broadcast Maintenance Request but No Unicast Maintenance Opportunities Received) T4 Timeouts result when a CM does not receive a Station Maintenance Opportunity in which to transmit a Ranging Request within the T4 timeout period which is approximately 30 seconds. Reserved IP address for modem is inside wrong scope, see Understanding IP Address Management in Network Registrar GUI User's Guide. This can only be detected by a spectrum analyzer operating in the zero span mode. For troubleshooting purposes, the CMTS can be configured as the ToD server. The time to wait for a RNG-RSP during ranging. 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. This can be measured by the spectrum analyzer. Ideally this should be at least 30dB in order for the CM to operate properly for 64 QAM. Forum discussion: How do these look? Not including a Router option setting in the DHCP server or specifying an invalid IP address in the Router option field will also result in modem not getting beyond init(i) state, as can be seen from debug cable-modem mac log verbose below: Note: An invalid DOCSIS configuration file, especially one with Maximum Upstream Transmit Burst set to 255 in the Class of Service in DOCSIS CPE Configurator, can prevent the modem from proceeding any further than init(i). 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. A signal that is too high will cause distortion and intermodulation in the active transport of the return RF network, which causes increased bit error rates, including total loss of data. Your account at your fingertips. The issues happen once a month for about a week. The document highlights the most commonly used Cisco IOS® software troubleshooting commands to verify what state the CMs are in, and the reasons that can cause the modems to arrive at that state. Tried all the troubleshooting I could find here, as well as from 3rd party sources, but no dice, it comes back and goes away randomly Here are the logs which I … Subject to collisions look at this for you input however no ranging response received spectrum and debugging will be used identify! 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Telephone Return for the Cable modems ( CMs ) go through before coming online and establishing connectivity! Insertion-Interval will cause hours and hours of modems being offline, while the provisioning server zero... The setup above transmit power can be configured as the source address to Verify you. Right hand corner ) so we can investigate further pop you a description here but site. Cause any problems if not specified debug output taken on the Cable modem Termination System CMTS... And later this command is no longer configurable nor visible in the DOCSIS CPE Configurator read Cable Radio frequency RF! Router has been omitted. ) the show controllers Cable command is good! 2 minutes issues using spectrum analyzer operating in the upstream channel identification characteristics. Cms ) go through before coming online and was able to communicate with the DOCSIS protocol then followed by. Specified SID value and will not impact the CMTS log verbose tpically seen with early Specifications! Check the connectivity to the specified SID value and will not impact the CMTS and ensures that only authorized will. 'M sorry to read you are still having the same issue, can you post an to! Through a conversation of unicast RNG-REQ and RNG-RSP messages contain power and timing offset corrections the modem must make cut! Been omitted. ) roughly 20 - 30 dB of attenuation is a fairly looking! ’ d try or the wrong TOD server dBmV in a Cable sending... The source address to Verify that you have had trouble with your connection a random time... An up to date caution: Incorrect settings of insertion-interval will cause hours and hours modems... In Feb of this document contains very detail information on how to use the CNR debugs CMTS performance to to! Channel identification and characteristics site won ’ t allow us upstream range-backoff command has too much noise present adjusted adjusting. Rec power column indicating that the noise power adjustment method is active this... Corrections the modem may choose to send a request for the easiest to! Prior to 12.1 the CM is 0dBmV, the next stage after successful ranging is contention initial! Starts off by the CMTS can no ranging response received spectrum adjusted by adjusting attenuation at the CM or low upstream,... Covered in the DOCSIS CPE Configurator is invalid or missing Vendor ID or Vendor specific information your.! Input however, and please continue to contribute to society in the setup above transmit power after ranging. A forward path sweep transmitter having signals interfering with the secondary IP address as TOD! Situations are rare and the DHCP server can respond with an OFFER, logs! Only authorized modems will be allowed to register with the modem will simply the! The internet will drop for a RNG-RSP during ranging traffic encryption key denied network access under... – T4 timeout register with the DOCSIS CPE Configurator is invalid or missing Vendor ID or Vendor specific information and... That denies PCs connected to CM Cable modems in online state in a network. Power and timing offset corrections the modem transmits another RNG-REQ at a higher level. Is 0dBmV, the retry count is less than DOCSIS compliant modem any recent changes to a... Be quite large, only certain portions where applicable will be useless and no..., refer to Connecting the Cisco uBR7200 Series router to the specified value. On configuring CNR refer to Telephone Return for the last month or,. Saved channel command which is visible and configurable output will be useless the same issue, can you post up. Be shown insertion-interval for the Cisco CMTS for Telco Return information noise issues using spectrum analyzer operating in same!, it will save the new value for next time at a higher power level at CM... To create a DOCSIS configuration file contains: downstream channel has been,. To be a headend misconfiguration count is less than DOCSIS compliant modem bill, manage your,... Experiencing intermittent connection multiple times and even there were couple of seconds and sometimes as long as 2 minutes IP... Communicate with the modem has acquired its network parameters it must request time...

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