Analysis And Realization Of The Megaco Protocol

Communication industry is driven by the requirements of the market.With the increasing requirements for diversity and higher performance,single voice communication is far from adequate to meet people's demands.Data,multimediahavebeenbecomingconsumer'surgent requirements.Thepublic switched telephone network whose core is the traditionalcircuit-switched technology centralizes service, call control and bear in thesame system. For the network system software is becoming more complexwith the booming service, network development and maintenance becomesvery difficult. The ever-growing demands will inevitably lead to greatchangesinthestructureofthetraditionalcommunicationnetwork.In order to support better voice, data and multimedia services,Soft-Switch Technology appeared. It separates service module, call controlmodule and bear module into independent equipment. Therefore it reducesthe coupling between modules greatly, supports good expandability forbusinesses and network size, and makes the integrating of communicationbusinesses come to a truth. The Megaco protocol was developed for thegatewayseparation.As a communication protocol between Media Gateway ControlEquipment and Media Gateway, or Media Gateway Control Equipment andMegaco terminals, Megaco plays an important role in building an open andmulti-network integrated Next Generation Networking. Megaco protocoldefines the operations between the Media Gateway Controller and theMediaGatewayon functions, andilluminates packages and attributes. It hasstrong interoperability and the ability to support service and wins highpraise of its functional flexibility and the ability to support service. It is themainstream protocol between Soft-Switch and Media Gateway, and isrecommended by domestic communication standards. Therefore, it hasrealistic significance to analyze and develop Megaco.This paper simulated a process of setting up bear of inner basic callafter analyzing the Megaco protocol, and solved the problem in our realworld by comparing the command and relevant parameters in this protocol.Firstly, I analyzed the structure of descriptor, command, action,transaction and message in Megaco protocol, and the relationship betweenthem. This paper illuminated the origin of the Megaco protocol and theposition of it in communication network. It made well preparations for thedevelopment with detailed analysis on parameters and comparison ondifferent values for some parameters.This paper proposed a solution to a communication problem in our realworld, hoping to solve it efficiently with lest money.We would encounter the problem in our daily life:During holidays, especially the Spring Festival, many people couldn'tmake a call or the call was removed unexpected when dialing. In case thesystem was stable, the main reason of the problem was lacking of resources.This paper analyzed the reasons from both economy and technology, andthen analyzed several solutions. Comparing the advantages anddisadvantages of these methods, this paper attempted to find an efficientway with lowest cost to solve this problem. This paper presented theborrowing Media Gateway and the developing process.The borrowing Media Gateway is something that some office (office1)borrows Media Gateway resources which encounters the situation ofinsufficient resources from office2 which has extra resources. Office2 sends"ServiceChange"to its Media Gateway indicating Media Gateway toregister in office1. If Media Gateway accepts the request it will sent"ServiceChange". After office1 goes through the peak, it will return theMedia Gateway resources back to office2 with the same process and paycertain amount of commission.This paper illuminated the advantage of the borrowing Media Gatewayfrom the customers, operators and equipment suppliers aspects. It couldresolve the lacking of Media Gateway resources satisfactorily, meet user'sservice requirements better, and enhance the reputation of enterprises. Thissolution was not only to retain old customers, but also to win trust of newcustomers. The equipment suppliers would be able to occupy the market,which met the operator's needs best. It would save a huge amount of capitalto solve the problem of insufficient Media Gateway resources through acertain data configurations. It was not necessary to buy extra equipment.The operators would purchase equipment from the company who suppliedthis solution. So it could meet the common interests of customers, operatorsand equipment suppliers.Secondly, in order to simulate the communication process of Megacoprotocol, this paper realized a basic call process. It describes the selection ofthe lower stack in detail, and then put forward several solutions. Aftercomparing the advantages and disadvantages of these solutions, in light ofthe actual requirements of Megaco protocol, we selected the mostappropriate one. This paper designed the process of the borrowing MediaGateway, and explained its process in detail. The software includedapplication module, multithreading module, message queue module,Megaco bottom-level structure module. Application module simulated abasic call, the process of borrowing Media Gateway and messageinterpretation. Application module might call other modules, whose mainrole was to control the entire process. The software supportedmulti-threading process. The message queue which ensured that messagewould not be lost because of lack of resources cooperated with theapplication module, managing the messages which need to be dealt with orbe sent out. Megaco bottom-level structure module included the definition,initialization and related process of Descriptor, Command, Action,Transaction and Message.This paper summarized the technology and application of Megacoprotocol, then looked forward to its important role in the futurecommunication network. It also proposed some issues to be solved.