Overview
Cyara reports have several failure categories, some of them self explanatory, some are specific to a test case, and one category that sometimes is hard to understand. This article is about Connection Errors in Cyara.
Reading Connection Errors
Cyara uses the following structure to display Connection Errors in Cyara Reports:
YYY-99-5XXX : User Friendly Description
Where
YYY - Q.850 Reason code, that may be optionally provided by PSTN Carrier, or SIP-to-PSTN Gateway in SIP Reason Header, according to RFC3326;
XXX - RFC3261 SIP Response Code.
Q.850 Reason Codes
Q.850 is a ITU-T recommendations describing the format, encoding and semantics of cause information elements in digital subscriber signalling system No.1 (ISUP) and the Signalling System No7 ISDN (SS7). Detailed information about these recommendations can be found ont the ITU-T Website.
The list of the most common Q.850 response codes is listed below:
|
Code |
Definition |
|
1 |
Unallocated Number |
|
2 |
No Route to Transit Network |
|
3 |
No Route to Destination |
|
4 |
Send Special Information tone |
|
5 |
Misdialed Trunk Prefix |
|
6 |
Channel Unacceptable |
|
7 |
Call Awarded in Established Channel |
|
8 |
Preemption |
|
9 |
Preemption - Circuit Reserved for Reuse |
|
16 |
Normal Call Clearing |
|
17 |
User Busy |
|
18 |
No User Responding |
|
19 |
No Answer from User (user alerted) |
|
20 |
Subscriber Absent |
|
21 |
Call Rejected |
|
22 |
Number Changed |
|
23 |
Redirection to New Destination |
|
25 |
Exchange Routing Error |
|
26 |
Non-selected User Clearing |
|
27 |
Destination Out of Order |
|
28 |
Invalid Number Format (addr incomplete) |
|
29 |
Facility Rejected |
|
30 |
Response to STATUS ENQUIRY |
|
31 |
Normal, Unspecified |
|
34 |
No Circuit/Channel Available |
|
38 |
Network Out of Order |
|
39 |
Permanent Frame Mode Connection OoS |
|
40 |
Permanent Frame Mode Connection Oper |
|
41 |
Temporary Failure |
|
42 |
Switching Equipment Congestion |
|
43 |
Access Information Discarded |
|
44 |
Requested Circuit/Channel N/A |
|
46 |
Precedence Call Blocked |
|
47 |
Resource Unavailable, Unspecified |
|
49 |
Quality of Service Not Available |
|
50 |
Requested Facility Not Subscribed |
|
53 |
Outgoing Calls Barred Within CUG |
|
55 |
Incoming Calls Barred Within CUG |
|
57 |
Bearer Capability Not Authorized |
|
58 |
Bearer Capability Not Available |
|
62 |
Inconsistency in Outgoing IE |
|
63 |
Service or Option N/A, unspecified |
|
65 |
Bearer Capability Not Implemented |
|
66 |
Channel Type Not Implemented |
|
69 |
Requested Facility Not Implemented |
|
70 |
Only Restricted Digital Bearer Cap supported |
|
79 |
Service or Option Not Implemented, Unspecified |
|
81 |
Invalid Call Reference Value |
|
82 |
Identified Channel Does Not Exist |
|
83 |
Call Exists, but Call Identity Does Not |
|
84 |
Call Identity in User |
|
85 |
No Call Suspended |
|
86 |
Call with Requested Call Identity has Cleared |
|
87 |
User Not Member of CUG |
|
88 |
Incompatible Destination |
|
90 |
Non-existent CUG |
|
91 |
Invalid Transit Network Selection |
|
95 |
Invalid Message, Unspecified |
|
96 |
Mandatory Information Element is Missing |
|
97 |
Message Type Non-existent / Not Implemented |
|
98 |
Message Incompatible With Call State or Message Type |
|
99 |
IE/Parameter Non-existent or Not Implemented |
|
100 |
Invalid Information Element Contents |
|
101 |
Message Not Compatible With Call State |
|
102 |
Recovery on Timer Expiry |
|
103 |
Parameter Non-existent / Not Implemented, Passed On |
|
110 |
Message With Unrecognized Parameter, Discarded |
|
111 |
Protocol Error, Unspecified |
|
127 |
Internetworking, Unspecified |
SIP Response Codes
Session Initiation Protocol is described by RFC 3261, a document that specifies standards of Session Initiation for media exchange.
Session Initiation Protocol (SIP) defines 6 types of Response Codes:
1XX - Provisional Responses
2XX - Success Responses
3XX - Redirection Responses
4XX - Request Failure Responses
5XX - Server Failure Responses
6XX - Global Failure Responses
This document is focused on Failure Responses: 4XX, 5XX, 6XX. The most typical SIP Failure Responses are listed below, a complete list can be found in the RFC3261.
4XX - Request Failure Response Codes
|
Code |
Definition |
| 400 Bad Request |
The request could not be understood due to malformed syntax. The Reason-Phrase SHOULD identify the syntax problem in more detail, for example, ""Missing Call-ID header field"". |
|
403 Forbidden |
The server understood the request, but is refusing to fulfill it. Authorization will not help, and the request SHOULD NOT be repeated. |
|
404 Not Found |
The server has definitive information that the user does not exist at the domain specified in the Request-URI. This status is also returned if the domain in the Request-URI does not match any of the domains handled by the recipient of the request. |
|
408 Request Timeout |
The server could not produce a response within a suitable amount of time, for example, if it could not determine the location of the user in time. The client MAY repeat the request without modifications at any later time. |
|
480 Temporarily Unavailable |
The callee's end system was contacted successfully but the callee is currently unavailable (for example, is not logged in, logged in but in a state that precludes communication with the callee, or has activated the ""do not disturb"" feature). The response MAY indicate a better time to call in the Retry-After header field. The user could also be available elsewhere (unbeknownst to this server). The reason phrase SHOULD indicate a more precise cause as to why the callee is unavailable. This value SHOULD be settable by the UA. Status 486 (Busy Here) MAY be used to more precisely indicate a particular reason for the call failure. |
|
482 Loop Detected |
The server has detected a loop. |
|
484 Address Incomplete |
The server received a request with a Request-URI that was incomplete. Additional information SHOULD be provided in the reason phrase. |
|
486 Busy Here |
The callee's end system was contacted successfully, but the callee is currently not willing or able to take additional calls at this end system. The response MAY indicate a better time to call in the Retry-After header field. The user could also be available elsewhere, such as through a voice mail service. Status 600 (Busy Everywhere) SHOULD be used if the client knows that no other end system will be able to accept this call. |
|
488 Not Acceptable Here |
The response has the same meaning as 606 (Not Acceptable), but only applies to the specific resource addressed by the Request-URI and the request may succeed elsewhere. |
5XX - Server Failure Response Codes
|
Code |
Definition |
| 500 Server Internal Error | The server encountered an unexpected condition that prevented it from fulfilling the request. The client MAY display the specific error condition and MAY retry the request after several seconds. If the condition is temporary, the server MAY indicate when the client may retry the request using the Retry-After header field. |
| 502 Bad Gateway | The server, while acting as a gateway or proxy, received an invalid response from the downstream server it accessed in attempting to fulfill the request. |
| 503 Service Unavailable | The server is temporarily unable to process the request due to a temporary overloading or maintenance of the server. The server MAY indicate when the client should retry the request in a Retry-After header field. If no Retry-After is given, the client MUST act as if it had received a 500 (Server Internal Error) response. A client (proxy or UAC) receiving a 503 (Service Unavailable) SHOULD attempt to forward the request to an alternate server. It SHOULD NOT forward any other requests to that server for the duration specified in the Retry-After header field, if present. Servers MAY refuse the connection or drop the request instead of responding with 503 (Service Unavailable). |
| 504 Server Time-out | The server did not receive a timely response from an external server it accessed in attempting to process the request. 408 (Request Timeout) should be used instead if there was no response within the period specified in the Expires header field from the upstream server. |
6XX - Global Failure Response Codes
|
Code |
Definition |
| 600 Busy Everywhere | The callee's end system was contacted successfully but the callee is busy and does not wish to take the call at this time. The response MAY indicate a better time to call in the Retry-After header field. If the callee does not wish to reveal the reason for declining the call, the callee uses status code 603 (Decline) instead. This status response is returned only if the client knows that no other end point (such as a voice mail system) will answer the request. Otherwise, 486 (Busy Here) should be returned. |
| 603 Decline | The callee's machine was successfully contacted but the user explicitly does not wish to or cannot participate. The response MAY indicate a better time to call in the Retry-After header field. This status response is returned only if the client knows that no other end point will answer the request. |
| 606 Not Acceptable | The user's agent was contacted successfully but some aspects of the session description such as the requested media, bandwidth, or addressing style were not acceptable. A 606 (Not Acceptable) response means that the user wishes to communicate, but cannot adequately support the session described. The 606 (Not Acceptable) response MAY contain a list of reasons in a Warning header field describing why the session described cannot be supported. This status response is returned only if the client knows that no other end point will answer the request. |
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