Early Media in SIP
Radhika Ranjan Roy · 2018
We describe early media in detail because it is an important feature for the Session Initiation Protocol (SIP) network for the generation of ringtone and others, for altering the SIP user before the establishment of the session. We explain the problems, including media clipping, that have been created by early media because of its peculiar behavior over the SIP network. A number of early-media solution models are discussed in dealing with its complicated characteristics based on the fact that it cannot be declined, modified, or identified by the receiving parties, or media and the codec of early media may not match at the receiving side as no negotiations are allowed. We also address the security implications of dealing with early media briefly, although more details about its security features are provided in Section 19.2.2.5 .