SIP Requests and Descriptions
In typical VoLTE point of view here is a list of all SIP messages and their meaning. In the rightmost column you can find the RFC number.
|INVITE||Indicates that a client is being invited to participate in a call session||RFC 3261|
|ACK||Confirms that the client has received a final response to an INVITE request||RFC 3261|
|BYE||Terminates a call; can be sent by either the caller or the called party||RFC 3261|
|CANCEL||Cancels any pending request||RFC 3261|
|OPTIONS||Queries the capabilities of servers||RFC 3261|
|PRACK||Provisional acknowledgement||RFC 3262|
|SUBSCRIBE||Subscribes to event notification||RFC 3265|
|NOTIFY||Notifies the subscriber of a new Event||RFC 3265|
|PUBLISH||Publishes an event to the Server||RFC 3903|
|INFO||Sends mid-session information that does not modify the session state||RFC 6086|
|REFER||Asks recipient to issue a SIP request (call transfer)||RFC 3515|
|MESSAGE||Transports instant messages using SIP||RFC 3428|
|UPDATE||Modifies the state of a session without changing the state of the dialog.||RFC 3311|
SIP Codes and Descriptions
SIP is based around request/response transactions, in a similar manner to the Hypertext Transfer Protocol (HTTP). Each transaction consists of a SIP request (which will be one of several request methods), and at least one response.
These codes are grouped according to their first digit as “provisional”, “success”, “redirection”, “client error”, “server error” or “global failure” codes, corresponding to a first digit of 1–6; these are expressed as, for example, “1xx” for provisional responses with a code of 100–199.
|181||Call is Being Forwarded|
|199||Early Dialog Terminated|
|4xx||Client Failure Response|
|405||Method Not Allowed|
|407||Proxy Authentication Required|
|412||Conditional Request Failed|
|413||Request Entity Too Large|
|414||Request-URI Too Long|
|415||Unsupported Media Type|
|416||Unsupported URI Scheme|
|422||Session Interval Too Small|
|423||Interval Too Brief|
|428||Use Identity Header|
|429||Provide Referer Identity|
|438||Invalid Identity Header|
|439||First Hop Lacks Outbound Support|
|469||Bad Info Package|
|481||Call/Transaction Does Not Exist|
|483||Too Many Hops|
|488||Not Acceptable Here|
|494||Security Agreement Required|
|5xx||Server Failure Response|
|500||Server Internal Error|
|505||Version Not Supported|
|513||Message Too Large|
|6xx||Global Failure Response|
|604||Does Not Exist Anywhere|
Nice collation of SIP info Prashant
This chaptered collection of VoLTE info/history is incredibly interesting; to the point where I struggled to continue reading despite actively falling asleep! I had to finish it upon waking up, which I did because the content was intriguing enough for me to remember wanting to finish. So I’d like to extend my gratitude for your thorough compilation of this information, thank you kindly sir.
Though still absolutely understandable as is, I could tell that English is not your first language. I’m not saying that as an insult, but rather to further exemplify just how amazingly impressed I am with this little VoLTE series.
In fact, I enjoyed it so much that I’d like to extend an offer to review it for grammatical improvements if you are interested. I’m not one with loads of excess time on my hands, but this just seems like such a great overview of recent mobile standards blunders/fixes/improvements. I’d be honored to help, and I certainly cannot do so from a technical perspective! So email me if you are open to such feedback.
Thanks again for these great posts!
its a great post about LTE.I never seen this type posts to understand easly,
thanks again and again by heart….
Thank you, great material
Thanks a lot. You are amazing.. 🙂
any one know what this error for?
Thanks a lot for this great stuff…Pls continue to provide the post on Signalling and voice traffic flow end to end, Call flow.
Very informative, nicely articulated
What will be the reason code for “No SIP session”?
Big Question. Which network error actually causes poor experience?
Which ones are fine and a redundant network will fix on its own?