SIP (Session Initiation Protocol): Difference between revisions

|The primary function that an SIP request is meant to call on a server. This method is carried in the request message itself.<ref name=":0">Microsoft [https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-sip/34204410-fb7e-4f02-8360-a6e225b34549#:~:text=An%20SIP%20message%20is%20either,methods%20are%20INVITE%20and%20BYE. Glossary]</ref>

|A SIP transaction occurs between a UAC and a UAS. The SIP transaction comprises all messages from the first request sent from the UAC to the UAS up to a final response (non-1xx) sent from the UAS to the UAC. If the request is INVITE, and the final response is a non-2xx, the SIP transaction also includes an ACK to the response. The ACK for a 2xx response to an INVITE request is a separate SIP transaction.<ref name=":0" />

*[https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-sip/34204410-fb7e-4f02-8360-a6e225b34549#:~:text=An%20SIP%20message%20is%20either,methods%20are%20INVITE%20and%20BYE. Microsoft&nbsp;Glossary]