Session Initiation Protocol Tutorial
SIP Useful Resources
Selected Reading
- SIP - B2BUA
- SIP - Codecs
- SIP to PSTN
- SIP - Proxies & Routing
- SIP - Forking
- SIP - Mobility
- SIP - The Offer/Answer Model
- SIP - Session Description Protocol
- SIP - Headers
- SIP - Response Codes
- SIP - Messaging
- SIP - Basic Call Flow
- SIP - Network Elements
- SIP - Introduction
- SIP - Home
SIP Useful Resources
Selected Reading
- Who is Who
- Computer Glossary
- HR Interview Questions
- Effective Resume Writing
- Questions and Answers
- UPSC IAS Exams Notes
SIP - Response Codes
SIP - Response Codes
A SIP response is a message generated by a user agent server (UAS) or SIP server to reply a request generated by a cpent. It could be a formal acknowledgement to prevent retransmission of requests by a UAC.
A response may contain some additional header fields of info needed by a UAC.
SIP has six responses.
1xx to 5xx has been borrowed from HTTP and 6xx is introduced in SIP.
1xx is considered as a provisional response and the rest are final responses.
| S.No. | Function & Description |
|---|---|
| 1 |
Informational responses are used to indicate call progress. Normally the responses are end to end (except 100 Trying). |
| 2 |
This class of responses is meant for indicating that a request has been accepted. |
| 3 |
Generally these class responses are sent by redirect servers in response to INVITE. They are also known as redirect class responses. |
| 4 |
Cpent error responses indicate that the request cannot be fulfilled as some errors are identified from the UAC side. |
| 5 |
This class response is used to indicate that the request cannot be processed because of an error with the server. |
| 6 |
This response class indicates that the server knows that the request will fail wherever it is tried. As a result, the request should not be sent to other locations. |