Abstract: Information regarding the present location of a dual-mode (or multi-mode) mobile station with respect to a plurality of communication systems is timely maintained by facilitating automated contact information modifications via, for example, a mobility management server (30). In a preferred approach, upon receiving a message (11) evidencing the supported presence of a mobile station in a first communication system comprising a wireless wide area network, one automatically responds (12) by modifying such contact information as is retained in a Session Initiation Protocol registrar. Testing (21) can be utilized to assure the propriety of making such alterations and/or deletions.

Abstract: A dispatch based call system configured to contact a call center using a single unique name or number. Multiple users are able to simultaneously dispatch the single generic call center number and communicate with a unique end station or individual at the call center. A user, or subscriber unit, when dispatching a call communicates initially with the service provider infrastructure. The infrastructure then establishes communication with the call center. The call center determines the identifier of an available end station and the subscriber is subsequently connected to the available end station.

Abstract: A method (600,700) and apparatus (800) are arranged and operate for facilitating call routing between sites in an enterprise connected by a private IP network (130). A range of identifiers (220-223) served by IP PBXs (120-123) in the enterprise may be registered with a SIP registrar (212) of an inter-site router (210). Call requests to a communication unit (350) outside the home site are routed to the SIP registrar. A site identifier associated with the destination IP PBX allows the call to be completed by the SIP Proxy or the IP PBX where the call was received. When no private IP network is available, a roaming CU registers with a cellular proxy in the visited network. Calls are routed by when an HLR (340) associated with the CU obtains the roaming number from the cellular proxy (330) in the visited site. The MSC completes the call to the visited IP PBX using the roaming number and a local SIP registrar 440 forwards the call to the CU.

Abstract: Methods and apparatus for facilitating mobility of the mobile stations in a wireless local area network (WLAN) allows uninterrupted communications as the mobile station moves. The method includes associating (501) a MNIP address (410) with the mobile station; establishing (502) a communications link between the mobile station and a first WLAN AP (109) in a first subnet (117) and associating (503) a first WLAN IP (420) address with the mobile station. Then using (505) the first WLAN IP address for an application that benefits from a persistent connection. Further included is establishing (507) a second communications link between the mobile station and a second WLAN AP 111 in a second subnet (119). When the mobile station is using the application, continuing to use the first WLAN IP address for communicating with the second subnet; and requesting (517) a second WLAN IP address in the second subnet when the persistent connection is no longer needed.

Abstract: The present application describes various embodiments that address the need in wireless environments and within the SIP framework to efficiently maintain SIP contact addresses. It introduces the concept of a SIP proxy user agent (UA) (e.g., 123 or 124) to serve as a gateway between a SIP core network and a SIP-unaware mobile (101). A new message is described, a combined registration and event subscription message, which is used by SIP proxy UAs to both register a new contact address for a mobile and to subscribe to the mobile's contact information. By updating and subscribing to the contact information, a SIP proxy UA is notified of subsequent changes to a mobile's contact information. Registration and deregistration of contact addresses can thus be effected in a manner that allows SIP contact addresses to be more efficiently maintained.

Abstract: A dispatch based call system configured to contact a call center using a single unique name or number. Multiple users are able to simultaneously dispatch the single generic call center number and communicate with a unique end station or individual at the call center. A user, or subscriber unit, when dispatching a call communicates initially with the service provider infrastructure. The infrastructure then establishes communication with the call center. The call center determines the identifier of an available end station and the subscriber is subsequently connected to the available end station.