The multimedia optimization control components (MOCCs) defined in this Recommendation are assistance entities which can obtain reliable information from the underlying network. This sort of information can be fed to multimedia applications and services and used as guidance services in the process of service node selection@ data traffic optimization and performance enhancement. The MOCC component is located between the multimedia applications and services layer and the network layer. MOCC entities will not be involved in actual data relay and transmission. The MOCC components can be deployed either in distributed multimedia systems or traditional client-server systems. They can be used in various networks such as NGN [ITU-T Y.2012]@ internet and other distributed systems. This Recommendation specifies requirements according to some typical scenarios.