SIP Server Error ResponsesAdded by IBM on November 30, 2011 | Version 1 (Original)
|The 5xx responses are failure responses given when a server itself has erred.
The 5xx responses are failure responses given when a server itself has erred.
Table 1. Server Error Responses
Parent topic: SIP Overview
|500||Internal Severe 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.|
|501||Not Implemented||The server does not support the functionality required to fulfill the request. This is the appropriate response when a UAS (User Agent Server) does not recognize the request method and is not capable of supporting it for any user. (Proxies forward all requests regardless of method.) Note that a 405 (Method Not Allowed) is sent when the server recognizes the request method, but that method is not allowed or supported.|
|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 (User Agent Client)) 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||Gateway Timeout||The server did not receive a timely response from an external server it accessed in attempting to process the request. The 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.|
|505||SIP Version Not Supported||The server does not support, or refuses to support, the SIP version that was used in the request. The server is indicating that it is unable or unwilling to complete the request using the same major version as the client, other than with this error message.|
|513||Message too Large||The server was unable to process the request since the message length exceeded its capabilities.|