Q931 Error Messages
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and AccessIntegrated Services Digital Networks (ISDN), Channel-Associated Signaling (CAS)Troubleshoot and AlertsConfiguration Example and TechNotes Troubleshooting ISDN BRI Layer 3 Using the debug isdn q931 Command Print Available Languages Updated:Feb 04,
Isdn Q931 Messages
2010 Document ID:9495 Contents Introduction Prerequisites Requirements Components Used Conventions Troubleshooting Prerequisites: Activating q931 call flow ISDN Layer 3 debugs Initiate the ISDN Call Troubleshooting Overview: Symptom and Resolution Procedure Troubleshooting: Symptom and Detailed Resolution Procedure The
Debug Isdn Q931 Output
Calling Router does not send a SETUP message The Called Router does not receive a SETUP message The Called Router does not send a CONNECT message The Calling Router does not receive a q.931 setup message format CONNECT message The Calling Router receives a CONNECT but the call still fails Related Information Introduction When troubleshooting ISDN call failure issues, it is important to keep in mind that the call could be failing due to any of the following: Dial-on-demand routing (DDR) ISDN Layers 1, 2 and 3 Point-to-Point Protocol (PPP): including link control protocol (LCP), Authentication or IP Control Protocol (IPCP) related issues. This cause code technologies document specifically focuses on ISDN related issues that cause call failures. This document also assumes that you have verified that ISDN Layers 1 and 2 on both ends of the circuit are functioning. Refer to Using the show isdn status Command for BRI Troubleshooting for more information on verifying ISDN Layer 1 and 2 status. Prerequisites Requirements There are no specific requirements for this document. Components Used This document is not restricted to specific software and hardware versions. The information presented in this document was created from devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If you are working in a live network, ensure that you understand the potential impact of any command before using it. Conventions For more information on document conventions, see the Cisco Technical Tips Conventions. Troubleshooting Prerequisites: Activating ISDN Layer 3 debugs Use the command debug isdn q931 on both ends to activate ISDN Layer 3 debugs. You should also have millisecond timestamps for debugs enabled on both routers. The timestamps are necessary to provide relative input to the troubleshooting process. Note:Activate millisecond timestamps for debugs using the following commands: maui-soho-01(config)#service timestamps debug datetime
systems like UDP, ISDN is connection oriented and uses explicit signalling to manage call state: Q.931. Q.931 typically does not carry user data. Q.931 does
Q931 Information Elements
not have a direct equivalent in the Internet Protocol stack, but can q850 cause codes be compared to SIP. Q.931 does not provide flow control or perform retransmission, since the underlying layers
Isdn Cause Codes Wiki
are assumed to be reliable and the circuit-oriented nature of ISDN allocates bandwidth in fixed increments of 64 kbit/s. Amongst other things, Q.931 manages connection setup and breakdown. http://www.cisco.com/c/en/us/support/docs/dial-access/integrated-services-digital-networks-isdn-channel-associated-signaling-cas/9495-isdn-q931-ts.html Like TCP, Q.931 documents both the protocol itself and a protocol state machine. Q.931 was designed for ISDN call establishment, maintenance, and release of network connections between two DTEs on the ISDN D channel. Q.931 has more recently been used as part of the VoIP H.323 protocol stack (see H.225.0) and in modified form in some mobile phone https://en.wikipedia.org/wiki/Q.931 transmission systems[2] and in ATM. A Q.931 frame contains the following elements: Protocol discriminator (PD) – Specifies which signaling protocol is used for the connection (e.g. PD=8 for DSS1) Call reference value (CR) – Addresses different connections which can exist simultaneously. The value is valid only during the actual time period of the connection Message type (MT) – Specifies the type of a layer 3 message out of the Q.931-defined Message type set for call control (e.g. SETUP). There are messages defined for the call setup, the call release and the control of call features. Information elements (IE) – Specify further information which is associated to the actual message. An IE contains the IE name (e.g. bearer capability), their length and a variable field of contents. Contents 1 Message examples 2 Disconnect causes 3 Q.2931 4 References Message examples[edit] Messages typically control or report the status of connections. For example: SETUP (indicating the establishment of a connection) CALL PROCEEDING (indicating that the call is being processed by the destination t
0 1 2 3 4 5 6 7 8 9 16 17 18 19 20 21 22 26 27 28 29 30 31 34 35 38 39 40 41 42 43 44 46 47 49 50 52 53 54 55 57 58 62 63 http://pbxbook.com/other/isdncode.html 65 66 69 70 79 81 82 83 84 85 86 87 88 90 91 95 96 97 98 99 100 101 102 103 110 111 127 128 Cause codes and definitions: 0 This is usually given by the router when none of the other codes apply. This cause usually occurs in the same type of situations as cause 1, cause 88, and cause 100. 1Unallocated (unassigned) number. This cause indicates that the destination requested by the calling user cause code cannot be reached because, although the number is in a valid format, it is not currently assigned (allocated). What it usually means: The SPIDS may be incorrectly entered in the router or the Telco switch, giving a SPID failure in the router logs. The ISDN phone number being dialed by the router is invalid and the telco switch cannot locate the number to complete the call. On long distance calls, the call cannot be properly routed to its destination. 2No q931 error messages route to specified transit network (national use). The equipment sending this cause has received a request to route the call through a particular transit network which it does not recognize. The equipment sending this cause does not recognize the transit network either because the transit network does not exist or because that particular transit network not serve the equipment which is sending this cause. 3No route to destination. The called party cannot be reached because the network through which the call has been routed does not serve the destination desired. Support for this cause is network dependent. 4Send special information tone. The called party cannot be reached for reasons that are of a long term nature, and the special information tone should be returned to the calling party. 5Mis-dialed trunk prefix (national use). Indicates the erroneous inclusion of a trunk prefix in the called party number. This number is to sniped from the dialed number being sent to the network by the customer premises equipment. 6Channel unacceptable. The channel most recently identified is not acceptable to the sending entity for use in this call. 7Call awarded. being delivered in an established channel. The user has been awarded the incoming call, and the incoming call is being connected to a channel already established to that user for similar calls (e.g. packet-mode x.25 virtual calls). 8Preemption. The call is being preempted. 9Preemption, circuit reserved for reuse. The call