for the transmission of new control-oriented H.245 conference request packets. Video Communications: The Whole Picture Dynamic Channel Replacement-Provides a streamlined method of changing modes between codecs that does not require two media decoders. Empty Capability Set-Enables gatekeeper to re-route connections to an endpoint that supports Supplementary Services (from one that does not). Endpoint Redundancy-Allows an endpoint to specify an alternate network interface or H.323-defined interface. Endpoint Type Prefixes and Data Rules-Enables gateways to specify data rates for each supported protocol, and to define prefixes for protocols. Gatekeeper Redundancy-Enables gatekeepers to specify backup gatekeepers if the primary contact fails. H.263-Improves video capabilities and provides new structures to improve the H.263 video stream. Keep Alive-Enables a gatekeeper to verify the status of a user and to act appropriately by allowing an endpoint to register with a gatekeeper and to inform the gatekeeper of all aliases. Pre-Granted Admission-Decreases call processing time by enabling endpoint pre- verification. QoS (Quality of Service)-Allows endpoints to set QoS parameters (e.g., RSVP) for media streams. RAS Retry Timers and Counters-Enhances RAS transaction processing by ensuring that messages arrive within a specified period, that they are re-sent when needed, and that end-users are notified or delivery failure. Reliable Information Request Response (IRR)-Introduces two new messages, IACK and INAK, to indicate whether messages were delivered. Request in Progress (RIP) Message-Allows the receiver of a request to specify, when a message cannot be processed before the initial timeout value expires, that a new timeout value should be applied. Resource Availability-Improves gatekeeper performance by enabling a gateway to notify it of the gateway's present call capacity. Time to Live-The duration for which a gatekeeper should keep a registration active. T.120/H.323 Integration-Requirement that endpoints that support bo