SIP 200 OK vs 400 Bad Request
SIP 200 (OK) is a 2xx Success response, while 400 (Bad Request) is a 4xx Client Failure response. 200 indicates that the request has succeeded. For INVITE, the call has been answered. For other methods, the action has been completed successfully. In contrast, 400 means that the request could not be understood due to malformed syntax. The client should not repeat the request without modifications.
Descripción
The request has succeeded. For INVITE, the call has been answered. For other methods, the action has been completed successfully.
Cuándo lo verás
When a call is answered (INVITE 200 OK), a registration succeeds (REGISTER 200 OK), or a subscription is accepted (SUBSCRIBE 200 OK).
Cómo solucionarlo
No fix needed — this is a success response. The caller should send an ACK to complete the three-way handshake for INVITE transactions.
Descripción
The request could not be understood due to malformed syntax. The client should not repeat the request without modifications.
Cuándo lo verás
When the SIP message has syntax errors, missing required headers, or invalid header values.
Cómo solucionarlo
Review the SIP message for syntax errors. Check required headers (To, From, Call-ID, CSeq, Via, Max-Forwards) and ensure proper formatting.
Diferencias clave
200 is a 2xx Success response, while 400 is a 4xx Client Failure response.
SIP 200: The request has succeeded. For INVITE, the call has been answered. For other methods, the action has been completed successfully.
SIP 400: The request could not be understood due to malformed syntax. The client should not repeat the request without modifications.
You encounter 200 when when a call is answered (INVITE 200 OK), a registration succeeds (REGISTER 200 OK), or a subscription is accepted (SUBSCRIBE 200 OK).
You encounter 400 when when the SIP message has syntax errors, missing required headers, or invalid header values.
Cuándo usar cada uno
For 200 (OK): No fix needed — this is a success response. The caller should send an ACK to complete the three-way handshake for INVITE transactions. For 400 (Bad Request): Review the SIP message for syntax errors. Check required headers (To, From, Call-ID, CSeq, Via, Max-Forwards) and ensure proper formatting.