what is a transanction sip protocol
The Session Initiation Protocol (SIP) is a signalling protocol used for controlling communication sessions such as Voice over IP telephone calls. 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.he SIP response codes are an extension to the HTTP response codes, although not all HTTP response codes are valid in SIP. SIP responses also specify a reason phrase, and a default reason phrase is defined with each response code.