The following table shows the most common errors that can appear in the SIP messages with a detailed explanation.
As it has been said they match with the following types:
4xx - Method Failures.
5xx - Server Failures.
6xx - Global Failures.
These SIP error messages can be translated into Q.931 or DSS1 error messages: The SIP errors and the DSS1 and Q.931 errors are mapped as you can see in the following table.
Table: Mapping between SIP events and DSS1 codes.
| SIP event |
Decimal
Cause number (DSS1) |
Hex.
Cause number (DSS1) |
Value as transmitted in D-channel |
Cause |
| 400 Bad request |
127 |
7f |
ff |
Interworking, unspecified |
| 401 Unauthorized |
57 |
39 |
b9 |
Bearer capability not authorized |
| 402 Payment required |
21 |
15 |
95 |
Call rejected |
| 403 Forbidden |
57 |
39 |
b9 |
Bearer capability not authorized |
| 404 Not found |
1 |
01 |
81 |
Unallocated (unassigned) number |
| 405 Method not allowed |
127 |
7f |
ff |
Interworking, unspecified |
| 406 Not acceptable |
127 |
7f |
ff |
Interworking, unspecified |
| 407 Proxy authentication required |
21 |
15 |
95 |
Call rejected |
| 408 Request timeout |
102 |
66 |
e6 |
Recover on Expires timeout |
| 409 Conflict |
41 |
29 |
a9 |
Temporary failure |
| 410 Gone |
1 |
01 |
81 |
Unallocated (unassigned) number |
| 411 Length required |
127 |
7f |
ff |
Interworking, unspecified |
| 413 Request entity too long |
127 |
7f |
ff |
Interworking, unspecified |
| 414 Request URI (URL) too long |
127 |
7f |
ff |
Interworking, unspecified |
| 415 Unsupported media type |
79 |
4f |
cf |
Service or option not available |
| 420 Bad extension |
127 |
7f |
ff |
Interworking, unspecified |
| 480 Temporarily unavailable |
18 |
12 |
92 |
No user response |
| 481 Call leg does not exist |
127 |
7f |
ff |
Interworking, unspecified |
| 482 Loop detected |
127 |
7f |
ff |
Interworking, unspecified |
| 483 Too many hops |
127 |
7f |
ff |
Interworking, unspecified |
| 484 Address incomplete |
28 |
1c |
9c |
Address incomplete (invalid number format) |
| 485 Address ambiguous |
1 |
01 |
81 |
Unallocated (unassigned) number |
| 486 Busy here |
17 |
11 |
91 |
User busy |
| 487 Request cancelled |
127 |
7f |
ff |
Interworking, unspecified |
| 488 Not acceptable here |
127 |
7f |
ff |
Interworking, unspecified |
| 500 Internal server error |
41 |
29 |
a9 |
Temporary failure |
| 501 Not implemented |
79 |
4f |
cf |
Service or option not implemented |
| 502 Bad gateway |
38 |
26 |
a6 |
Network out of order |
| 503 Service unavailable |
63 |
3f |
bf |
Service or option unavailable |
| 504 Gateway timeout |
102 |
66 |
e6 |
Recover on Expires timeout |
| 505 Version not implemented |
127 |
7f |
ff |
Interworking, unspecified |
| 580 Precondition Failed |
47 |
2f |
af |
Resource unavailable, unspecified |
| 600 Busy everywhere |
17 |
11 |
91 |
User busy |
| 603 Decline |
21 |
15 |
95 |
Call rejected |
| 604 Does not exist anywhere |
1 |
01 |
81 |
Unallocated (unassigned) number |
| 606 Not acceptable |
58 |
3a |
ba |
Bearer capability not presently available |
