The Research And Design Of Embedded SIP Server

SIP(Session Initiation Protocol) is drafted by IETF(Internet Engineering TaskForce) in1999, it is a application-layer signa ling control protocol, and is responsib lefor session creating, session mod ifying, and session terminating o f a ll inter-clients. Itprovides a flexib le solution for inte grating traditio nal te lecom app licatio ns withinternet va lue-added services, whic h inc lude voice, image, v ideo and other IPapplications. It is widely used in the ne xt generation network applicatio ns.In the app licatio n systems that based on the SIP protocol, the SIP server is thecore of the who le syste m, it provides the services (such as registratio n, proxy andredirection) for SIP termina ls. With the rapid deve lopment o f e mbedded technolo gy,the application of embedded network communicatio n equip ments, inc lud ing theinte llige nt mob ile phone, audio and video gateway, and network co mmunicationserver, becomes more and more widely. The comb ination of S IP protoco l andembedded system is the ma in deve lopme nt directio n of SIP co mmunicationequip ments.Based on the research of SIP protocol a nd embedded syste m, an e mbedded SIPserver is designed in this artic le, after testing the syste m, it can provide services forthe audio and video communication establis hment between SIP termina ls, and hasadvanta ges of the embedded system, such as low cost, low power consumptio n, highreliability and real-time.The artic le mainly comp letes the fo llowing several aspects of the work:(1) Analyzes the SIP protocol sta ndard--RFC3261, includ ing the la yeredstructure of SIP protocol, message signa ling, SIP transactio n, basic structureof SIP protocol application s ystem, a nd the call contro l process of SIPsessio n, etc.(2) Selects the S5PV210processor of ARM Cortex-A8architecture as the corecontro ller, designs periphera l interface circ uits, inc lud ing the power circ uit,network interface circuit, serial port circ uit, LCD interface circ uit a nd USBinterface circ uit.(3) Transpla nts the Linux operating system to the hardware platform; ana lyzesthe source code of oSIP (an open source SIP protocol stack), and researchesits parser module, state machine module, tool module; on the basis of oSIP protocol stack, this article imp le ments the embedded SIP server’sauthenticatio n module, register server module, proxy server module, andredirect server module by us ing C la nguage in the Linux enviro nment.(4) Builds the testing p latform, in the LAN environme nt, SIP termina ls areselected to test the function and the ca ll set up time of e mbedded SIP server;the SIPp, a kind of concurrent performance test tools, is selected to do thestress test. And the results of these tests achieve the desired effect.