Nortel Networks Corporation

Genband US LLC

Rockstar Consortium US LP

Cristian Constantinof

Dany Sylvain

Julian Francis Cheesman

Michael C Kahnert

Kim Brian Holmes

Vladimir V Mikhailov

Mingxing Li

Klaas Van Weringh

Brian J N Vaughan

The present invention relates to providing services for circuit-switched calls from an Internet Protocol (IP) based packet network. In essence, a call originating from or intended for a subscriber that is served by a telephony switch, such as an end office or mobile switching center, in a circuit-switched network is intercepted and routed by the telephony switch to a service node via a subscriber emulator. The subscriber emulator acts as a liaison between the telephony switch of the circuit-switched network and the service node of the packet network. Preferably, the subscriber emulator presents itself to the service node as a user agent, which acts on behalf of a subscriber that is served the telephony switch. The service node provides any requisite processing of the call to implement services for the call.

Controlling services in a circuit-switched network from a packet network

The present invention provides a technique for facilitating emergency services via packet networks. Emergency service providers will implement emergency proxies to ensure that proper call setup requests for emergency services are forwarded to the appropriate entities, even if those entities are in overload conditions. The emergency proxies may authenticate and filter call setup requests to ensure that only proper call setup requests are forwarded to help prevent such overload conditions. The emergency proxies may operate solely in a packet network, as well as at the interface between a packet network and a circuit-switched network to assist in call setup requests originating from either the packet network or the circuit-switched network.

Emergency services for packet networks

The present invention moves service control, including call control, for a user element from any number of subsystems to a multimedia subsystem (MS). Call control for originating or terminating a call in any subsystem as well as transferring the call between user elements is anchored at a continuity control function (CCF) in the MS. A call may be transferred by the CCF from a first user element to a second user element in the same or different subsystems upon receiving a request from the second user element. A user may invoke a transfer from the first user element to the second user element by having the second user element send an appropriate request to the CCF. The request may be provided to the CCF by initiating a call from the second user element that is intended for the CCF, when the call with the first user element is active.

Voice continuity among user terminals

The present invention provides a service node, which extends the services of a carrier's multimedia subsystem (MS), such as an IP multimedia subsystem (IMS), to enterprise networks in an efficient and effective manner. As such, MS subscribers gain access to enterprise services in addition to the carrier's services provided via the carrier's circuit switched subsystems (CS) and packet subsystems (PS). The service node acts as a liaison between enterprise application servers and the MS, such that the enterprise application servers appear as MS application servers to the MS. The service node provides user identifier and protocol translation between enterprise and MS user identifiers and protocols, respectively. As such, enterprise application servers can access the MS as well as be accessed by the MS to support user mobility, with continuity of services, between the enterprise and carrier networks.

Enterprise mobility

The present invention provides a session filter associated with an element to be protected in a communication network. Session requests intended for the protected element are processed by the session filter prior to being forwarded to the protected element. The protected element or a device associated therewith will provide event information indicative of undesirable session conditions, such as an overload condition, which necessitates a reduction or stoppage of incoming session requests for the protected element. The session filter will directly or indirectly receive the event information and take steps to reduce or stop the session requests being sent to the protected element. The session filter may filter the incoming session requests for the protected element and selectively send select session requests to the protected element, as well as send system protection responses to minimize the number of new session requests to devices generating or forwarding the incoming session requests.

Method and apparatus for session control

A method and apparatus for reduction of call setup rate in an ATM network are described. The method and apparatus are particularly useful in ATM networks used for the transfer of bearer traffic between telephone switching offices. The method involves caching a number of switched virtual circuits (SVCs) between edge interfaces to the ATM network. A cache connection is an emulated circuit between two edge interfaces that is available and idle. The apparatus provides a central policy manager which computes and distributes cache policies to cache managers located in the edge interfaces. The cache managers manage pools of cached SVCs established between two edge interfaces. The method and apparatus reduces the number of connection setup requests sent to the ATM switches. The advantage is the ability to use ATM switches which have slow connection setup rates to provide commercially acceptable telephone services in an efficient manner. The method can also be used with fast ATM switches when they become available to balance the use of bandwidth and switch resources to reduce overall cost.

Method and apparatus for reduction of call setup rate in an ATM network

A telecommunication system and method of signalling are disclosed which enable service providers to integrate broadband network capability into their existing narrow band networks while being substantially transparent to existing narrow band signalling infrastructures such as the Common Channel Signalling System Number 7 (CCS7), currently in use. Significant advantages are realized through such a network system. Service providers, for example incumbent local exchange carriers (ILECs) now have access to BB connectivity while retaining the use of their extensive CCS7 signalling networks and Advanced Intelligent Network (AIN) resources. Investment in the CCS7 signalling infrastructure is hence not lost and the proven robustness and reliability of these networks is retained. Service providers can continue to take advantage of Intelligent Network capabilities in providing a large variety of voice services, but also to make available some of the current service features for future BB services. Furthermore each network is virtually independent of the other and can evolve as such. Telephony service call related signalling is able to be kept separate from the broadband network connectivity signalling thus allowing service providers to evolve their service specific signalling requirements independently of whatever BB networks are used now or in the future.

Telephony system and method of signalling

The present invention is related to a transit trunk subnetwork system which is configured to expand the existing capacity for bearer traffic in telephone networks. The invention incorporates an asynchronous transfer mode subnetwork which is interfaced directly with existing local exchange end offices, access tandems, or combinations thereof. A signal controller is utilized to direct signal messaging across the asynchronous transfer mode subnetwork to set up the movement of bearer traffic across the subnetwork. A network manager is also utilized to control bandwidth availability at the interfaces with the asynchronous transfer mode subnetwork.

Transit trunk subnetwork system

A method and apparatus are disclosed for completing inter-switch calls using a single large trunk group connected to ATM facilities. In a first embodiment, all non-featured inter-switch calls are routed to the ATM facilities over the single large trunk groups. In a second embodiment, all inter-switch calls are routed to the ATM facilities over the single large trunk group. A call manager associated with the signaling network and the ATM facilities controls call routing. The advantage is a significant simplification in the translation and routing tables at the switches in the telephone network, resulting in significant savings related to the maintenance of a plurality of trunks groups at each switch.

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Kanata, Canada

Cristian Constantinof