Abstract: In one embodiment, a network device determines one or more conditions for invoking one or more real applications to the network device for a session. This determination may be made at the initiation of the session, such as when a SIP INVITE message is received. The one or more conditions allow real applications to be invoked when a future event satisfies the condition. When it is determined that a condition is satisfied, a real application associated with the condition is then invoked. Accordingly, conditions may be set for real applications that may be tested against future events that have not yet occurred. This allows deferred invocation of real applications. Accordingly, if real applications are not needed for a session, then they are not invoked. But, when a real application is needed, it can be invoked.

Abstract: In one embodiment, a network device determines one or more conditions for invoking one or more real applications to the network device for a session. This determination may be made at the initiation of the session, such as when a SIP INVITE message is received. The one or more conditions allow real applications to be invoked when a future event satisfies the condition. When it is determined that a condition is satisfied, a real application associated with the condition is then invoked. Accordingly, conditions may be set for real applications that may be tested against future events that have not yet occurred. This allows deferred invocation of real applications. Accordingly, if real applications are not needed for a session, then they are not invoked. But, when a real application is needed, it can be invoked.

Abstract: In one embodiment, a network device determines one or more conditions for invoking one or more real applications to the network device for a session. This determination may be made at the initiation of the session, such as when a SIP INVITE message is received. The one or more conditions allow real applications to be invoked when a future event satisfies the condition. When it is determined that a condition is satisfied, a real application associated with the condition is then invoked. Accordingly, conditions may be set for real applications that may be tested against future events that have not yet occurred. This allows deferred invocation of real applications. Accordingly, if real applications are not needed for a session, then they are not invoked. But, when a real application is needed, it can be invoked.

Abstract: A packet-switched communication system, method for controlling packet-switched calls over such a system, and components of the system are disclosed. In one embodiment, the system provides a scalable implementation for handling H.323 calls. The H.323-required TCP signaling terminations are handled by distributed signaling gateways. Each signaling gateway backhauls the signaling content from these terminations to a central media gateway controller for processing. The media gateway controller uses an efficient gateway control protocol to control media gateways and/or media proxies that actually handle the media bearer channels associated with the backhauled H.323 signaling connections. The H.323 complexity can thus be concentrated in the media gateway controller, without requiring full H.323 functionality at the distributed gateways. Also, because the TCP signaling connections are remote from the media gateway controller, H.323 signaling redundancy can be provided at the media gateway controller.

Abstract: In one embodiment, a network device determines one or more conditions for invoking one or more real applications to the network device for a session. This determination may be made at the initiation of the session, such as when a SIP INVITE message is received. The one or more conditions allow real applications to be invoked when a future event satisfies the condition. When it is determined that a condition is satisfied, a real application associated with the condition is then invoked. Accordingly, conditions may be set for real applications that may be tested against future events that have not yet occurred. This allows deferred invocation of real applications. Accordingly, if real applications are not needed for a session, then they are not invoked. But, when a real application is needed, it can be invoked.

Abstract: A mechanism that provides for communication of heartbeat signals from servers (call agents) to clients (gateways) in a packet telephony network environment. Clients listen for receipt of multicast heartbeats from any of the servers that may be part of a multicast group. A client assigned to a particular server for control messaging, upon failure to receive a response to a message sent to the assigned server and failure to receive a heartbeat from the assigned server, may select a second server from among the servers and re-send the message to the second server. Without receipt of heartbeat signals, the client defaults to a normal retry behavior for re-sending the message first to the assigned server a number of times before attempting to re-send the message to the second server.