Session Initiation Protocol and Services
In this paper, the authors discusses about the Session Initiation Protocol and the call setup between the user agents with scenarios like single proxy server and multiple proxy servers of different domains. The messages and the parameters of those calls are analyzed in detail. Scenarios for a call flow with and without record are discussed, explaining the various system entities of a SIP network. The session description protocol is elaborated as to how it is related to SIP. The concept of Instant Messaging and Presence is studied and the pros and cons of SIMPLE and Jabber protocols are indicated. The global unique numbering concept, ENUM is explained with a real time example.