ISDN Diagnostic Codes

Transcription

1 ISDN Diagnostic Codes See also: Error Messages - Main Menu Cause Code (Dec) Value in trace (Dec) Cause Code (Hex) Value in trace (Hex) Meaning Category 0 - normal event Normal Disconnect Unassigned (Unallocated number) No route to specified transit network No route to destination Send special information tone* Misdialled trunk prefix* Channel unacceptable Call awarded and being delivered in an established channel Preemption* Preemption, circuit reserved for re-use* Category 1 - normal event Normal call clearing User busy No user responding User alerting, no answer Subscriber absent* Call rejected Number changed Redirection to new destination* Exchange routing error* A 9A Non-selected user clearing B 9B Destination out of order C 9C Invalid number format D 9D Facility rejected E 9E Response to STATUS ENQUIRY F 9F Normal unspecified Category 2 - resource unavailable A2 No circuit/channel available A6 Network out of order A7 Permanent frame mode connection out of service* A8 Permanent frame mode connection operational*

2 A9 Temporary failure A AA Switching equipment congestion B AB Access information discarded C AC Requested circuit/channel not available E AE Precedence call blocked* F AF Resource unavailable, unspecified Category 3 - service or option not available B1 Quality of service unavailable B2 Requested facility not subscribed B5 Outgoing calls barred within CUG* B7 Incoming calls barred within CUG* B9 Bearer capability not authorized A BA Bearer capability not presently available F BF Service or option not available, unspecified Category 4 - service or option not implemented C1 Bearer capability not implemented C2 Channel type not implemented C5 Requested facility not implemented C6 Only restricted information bearer capability available F CF Service or option not available, unspecified Category 5 - invalid message (e.g. parameter out of range) D1 Invalid call reference value D2 Identified channel does not exist D3 A suspended call exists, but this identity does not D4 Call identity in use D5 No call suspended D6 Call having the requested call identity has been cleared D7 User not a member of CUG* D8 Incompatible destination A DA Non-existent CUG* B DB Invalid transit network selection F DF Invalid message, unspecified Category 6 - protocol error (e.g. unknown message) E0 Mandatory Information Element is missing E1 Message type non-existent or not implemented E2 Message not compatible with call state, or not implemented E3 Information Element non-existent or not implemented

3 E4 Invalid Information Element contents E5 Message not compatible with call state E6 Recovery on time expiry E7 Parameter not implemented* F EF Protocol Error, unspecified Category 7 - interworking F FF Interworking, unspecified Extracting ISDN Cause Codes from a trace See also: Introduction to DiTrace - please read this first ISDN cause codes ISDN location codes When using ISDN, it is useful to be able to interpret the information returned by RELEASE and DISCONNECT frames, since this gives the reason that a call has been disconnected or refused. You see the DISCONNECT or RELEASE frames in one of two situations: 1. When a call SETUP has been issued, the device at the other end (or the network itself) can refuse to connect the call by sending DISCONNECT or RELEASE. 2. When a call is already connected (i.e. the SETUP was met with a CONNECT message, and a pointto-point connection is now established), then either party can end the call by sending a DISCONNECT. Also, the network itself might end the connection (for example, if some network equipment fails or the network becomes congested). The information that we are interested in is coded in an 'information element' present on RELEASE, DISCONNECT and STATUS messages called 'cause'. The whole information element consists of 4 bytes; for instance: BF The "08" means "Cause" and the "02" means that two further bytes of information follow. So, the 'cause' is '82 BF'. These further two bytes break down into bit fields as follows: Coding 0 Location Cause Value The Coding field gives the Coding Standard, showing what standard you need to refer to in order to understand the Cause Value. Generally, coding standard will be "00" means CCITT standard, which is also used for the ETSI standard (EuroISDN). For completeness, Coding Standard field can be one of the following: 00 CCITT standardized 01 reserved for national standards 10 national standard 11 standard specific to identified location The Location field shows who issued this diagnostic code. This is useful information where the two communicating devices are on different ISDN networks (perhaps with one or more transit networks between), or are using ISDN though private network such as a PABX. The possible location codes are:

4 Binary Hex Value in trace user Meaning private network serving the local user public network serving the local user transit network public network serving the remote user private network serving the remote user international network 1010 A 8A network beyond interworking point More information on what these codes mean In the example trace above, value for this byte is 0x82 (in binary this is ), so we can break this down as follows: This bit is always Coding Standard = CCITT This bit is always Location is "public network serving the local user" The Cause Value field is where the diagnostic code itself appears. Note that the top bit is always set, so in fact we only need to look at the lower 7 bits when we look up this value. In the example above, we have the value 0xBF which decodes as follows: This bit is always Code is 0x3F (63 in decimal) which means "Service or option not available, unspecified". When we interpret the value 0x3F, we know that we use the CCITT list because the Location field (in the previous byte) told us so. In fact there is more information that we can get from the Cause code because the first three bits give a general category of error, and the last four bits give the error within the category. The categories are: 000 normal event 001 normal event 010 resource unavailable 011 service or option not available 100 service or option not implemented 101 invalid message (e.g. parameter out of range) 110 protocol error (e.g. unknown message) 111 interworking So the breakdown of code 0xBF is actually as follows: This bit is always Category is "service or option not available" Code is 0xF in category 3, "Service or option not available, unspecified". Line Check Errors See also: Error Messages - Main Menu About Line Check

5 Success! Line Check test passed Failure! No ISDN card found. DIVA software not correctly installed Failure! ISDN card does not work correctly. Installation probably not correct Failure! Unknown error. A resource conflict probably exists in your system or the DIVA card has been removed Failure! Test aborted with an error - Layer 1 error. Check cable/nt! - TEI Error - Layer 2 error Failure! Unknown error. Please contact support Success! Line Check test passed. This is the successful (and desired) outcome of the Line Check test. It indicates that the DIVA card is installed correctly and is communicating with the network. This is not an exhaustive test and does not necessarily mean that all calls placed through the card will always work. Failure! No ISDN card found. DIVA software not correctly installed. This Line Check utility is unable to locate any DIVA card in your system. Follow these instructions for problem diagnosis on Windows 95/98 and these instructions for Windows NT. Failure! ISDN card does not work correctly. Installation probably not correct. The Line Check utility has located a DIVA card on your system, but is unable to communicate with it. Follow these instructions for problem diagnosis on Windows 95/98 and these instructions for Windows NT. Failure! Unknown error. A resource conflict probably exists in your system or the DIVA card has been removed. The Line Check utility has located a DIVA card on your system, but is unable to communicate with it. This is probably due to a conflict with other devices in your computer. Follow these instructions for problem diagnosis on Windows 95/98 and these instructions for Windows NT. Failure! Test aborted with an error. The message will report some additional information: Layer 1 error. Check cable/nt! Check that the cable is plugged into the DIVA card. In the case of a DIVA Server 4BRI, check that the cable is

6 connected to the port that you are testing. Beware if you have LAN adapter in your PC that you have not connected the ISDN line to this card. TEI Error. Repeat the test. If the problem is persistent, you may need to change the card configuration to match your ISDN line. Layer 2 error. Repeat the test. Some ISDN switches are sensitive to equipment being unplugged and will cause this error. If the problem is persistent, this needs in-depth analysis using the DiTrace tool. Use this link for Windows 95/98 and this link for Windows NT. Failure! Unknown error. Please contact support. Internal Line Check error. Location codes See also: Diagnostic codes Extracting 'Cause' information from a trace MDL Errors Error Messages - Main Menu An ISDN Cause code consists of 2 bytes; the first byte contains the 'location' code (with some other information) and the second byte contains the diagnostic code. The Location field shows who issued the diagnostic code. This is particularly useful information where the two communicating devices are on different ISDN networks (perhaps with one or more transit networks between), or are using ISDN though a 'private network' such as a PABX. The possible location codes are: Location code (Hex) Value in trace 0 80 user Meaning (Click on a link below to highlight the component) 1 81 private network serving the local user 2 82 public network serving the local user 3 83 transit network 4 84 public network serving the remote user 5 85 private network serving the remote user 7 87 international network A 8A network beyond interworking point

7 MDL Errors See also: Diagnostic codes Location codes Extracting 'Cause' information from a trace Other errors The following table shows errors reported by the MDL-ERROR-INDICATION primitive to do with layer- 2 establishment on the "D" channel. MDL is the standard prefix for messages to do with communication between layer management and the data link layer. In a DIVA trace, these codes appear in messages 'MDL-ERROR(x)', where 'x' is one of the following error codes. Error Code Error Condition Action Error Type A Supervisory (F=1) Error Log Receipt of unsolicited B DM (F=1) Error Log Receipt of unsolicited C UA (F=1) TEI removal procedure or TEI check procedure, then if TEI: free: remove TEI single: no action multiple: TEI removal procedure D UA (F=0) TEI removal procedure or TEI check procedure, then if TEI: free: remove TEI single: no action multiple: TEI removal procedure Receipt of unsolicited Receipt of unsolicited E DM (F=0) Error Log Receipt of unsolicited F SABME Error Log Peer initiated re-establish. G SABME TEI check procedure, then if TEI: free: remove TEI single: no action multiple: TEI removal Unsuccessful retransmission (N200 times)

8 procedure H DISC TEI check procedure, then if TEI: free: remove TEI single: no action multiple: TEI removal procedure Unsuccessful retransmission (N200 times) I Status Enquiry Error Log Unsuccessful retransmission (N200 times) J N(R) error Error Log Other K Receipt of FRMR Error Log Other L M N Receipt of frame with undefined control field Receipt of I field not permitted Receipt of frame with wrong size Error Log Error Log Error Log Other Other Other O N201 error Error Log Other Adapted from ETS