SIP responses are the codes used by Session Initiation Protocol for communication.
They complement the SIP Requests,
which are used to initiate action such as a phone conversation.
Note that the Reason Phrases of the responses listed below are only the recommended examples,
and can be replaced with local equivalents without affecting the protocol. |
| 1xx | Informational Responses |
|---|
| 100 | Trying: extended search being performed may take a significant time so a forking proxy must send a 100 Trying response |
| 180 | Ringing |
| 181 | Call Is Being Forwarded |
| 182 | Queued |
| 183 | Session Progress |
| 2xx | Successful Responses |
|---|
| 200 | OK |
| 202 | accepted: It Indicates that the request has been understood but actually can't be processed |
| 3xx | Redirection Responses300 Multiple Choices |
|---|
| 301 | Moved Permanently |
| 302 | Moved Temporarily |
| 305 | Use Proxy |
| 380 | Alternative Service |
| 4xx | Client Failure Responses |
|---|
| 400 | Bad Request |
| 401 | Unauthorized (Used only by registrars or user agents. Proxies should use proxy authorization 407) |
| 402 | Payment Required (Reserved for future use) |
| 403 | Forbidden |
| 404 | Not Found (User not found) |
| 405 | Method Not Allowed |
| 406 | Not Acceptable |
| 407 | Proxy Authentication Required |
| 408 | Request Timeout (Couldn't find the user in time) |
| 409 | Conflict |
| 410 | Gone (The user existed once, but is not available here any more.) |
| 412 | Conditional Request Failed |
| 413 | Request Entity Too Large |
| 414 | Request-URI Too Long |
| 415 | Unsupported Media Type |
| 416 | Unsupported URI Scheme |
| 417 | Unknown Resource-Priority |
| 420 | Bad Extension (Bad SIP Protocol Extension used, not understood by the server) |
| 421 | Extension Required |
| 422 | Session Interval Too Small |
| 423 | Interval Too Brief |
| 424 | Bad Location Information |
| 428 | Use Identity Header |
| 429 | Provide Referrer Identity |
| 433 | Anonymity Disallowed |
| 436 | Bad Identity-Info |
| 437 | Unsupported Certificate |
| 438 | Invalid Identity Header |
| 480 | Temporarily Unavailable |
| 481 | Call/Transaction Does Not Exist |
| 482 | Loop Detected |
| 483 | Too Many Hops |
| 484 | Address Incomplete |
| 485 | Ambiguous |
| 486 | Busy Here |
| 487 | Request Terminated |
| 488 | Not Acceptable Here |
| 489 | Bad Event |
| 491 | Request Pending |
| 493 | Undecipherable (Could not decrypt S/MIME body part) |
| 494 | Security Agreement Required |
| 5xx | Server Failure Responses |
|---|
| 500 | Server Internal Error |
| 501 | Not Implemented: The SIP request method is not implemented here |
| 502 | Bad Gateway |
| 503 | Service Unavailable |
| 504 | Server Time-out |
| 505 | Version Not Supported: The server does not support this version of the SIP protocol |
| 513 | Message Too Large |
| 580 | Precondition Failure |
| 6xx | Global Failure Responses |
|---|
| 600 | Busy Everywhere |
| 603 | Decline |
| 604 | Does Not Exist Anywhere |
| 606 | Not Acceptable |
Siemens 7xx-Extended Codes
Attention: The following is a list of SIP Codes belonging to the 7xx, 8xx, 9xx classes (applicative) and used by Siemens in their Gigaset products.
They are not documented by any SIP RFC and other companies and applications may override them without notice. |
| 701 | The called party has hung up |
| 702 | VoIP socket error |
| 703 | Connection cancelled because of timeout |
| 704 | Connection interrupted because of a SIP error |
| 705 | SIP memory error |
| 706 | SIP transaction memory error |
| 751 | Busy tone: No codec match between the calling and called party |
| 810 | General socket layer error. |
| 811 | General socket layer error: Wrong socket number |
| 812 | General socket layer error: Socket is not connected. |
| 813 | General socket layer error: Memory error |
| 814 | General socket layer error: Socket not available – check IP settings/connection problem/VoIP setting incorrect |
| 815 | General socket layer error: Illegal application on the socket interface |
| 922 | No DNS server known |
| 923 | DNS name resolution failed |
| 924 | Insufficient resources for DNS name resolution |
| 925 | URL error |
SIP Error Messages
The following table shows the most common errors that can appear in the SIP messages with a detailed explanation.
These SIP error messages can be translated into Q.931 or DSS1 (ISDN) 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 | Hex | DSS1 HEX | 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 |
