Part of the IETF standards (RFC 2705). The IETF and the ITU have decided to endorse and jointly mandate a single standard, known in the IETF as Megaco and known in the ITU as H.248. Megaco/H.248 is a master-slave protocol, where external call controllers execute commands that the media gateways must follow. Megaco/H.248 represents an enhancement of MGCP because it supports multiple gateways, thousands of ports on a gateway, and connection-oriented media such as TDM and ATM.