Abstract: A method of controlling an application media session between at least two network entities, which comprises establishing a Session Initiation Protocol, SIP, session between each network entity and a SIP application server within the IMS and establishing a media session between each network entity and a Media Resource Function, MRF, controlled by the SIP application server. The method further comprises sending between the network entities, via the media sessions, control messages comprising application control protocol instructions.

Abstract: A Home Subscriber Server for handling IP Multimedia Subsystem subscriptions comprises means for maintaining associations between public user identities and Service Profiles, where two or more public user identities can be associated with a common Service Profile, and means for identifying to a network node all public user identities that are associated with a common Service Profile.

Abstract: A method of controlling an application media session between at least two network entities, which comprises establishing a Session Initiation Protocol, SIP, session between each network entity and a SIP application server within the IMS and establishing a media session between each network entity and a Media Resource Function, MRF, controlled by the SIP application server. The method further comprises sending between the network entities, via the media sessions, control messages comprising application control protocol instructions.

Abstract: The invention relates to a method of notifying an Application Function, AF, in a communications network of resource restrictions relating to a communications session. The network includes a Policy and Charging Rules Function, PCRF, for authorising and controlling flows of data in the session. In the method the AF sends an authorisation request to the PCRF for establishing the communication session. The authorisation request includes an indication that the AF is to be notified of resource restrictions for the data flows in the session. The PCRF notifies the AF of the resource restrictions.

Abstract: The invention relates to a method of changing allocation of Serving-Call Session Control Functions (S-CSCFs) to a user of an IMS network. The user is being provided with services via a first S-CSCF allocated to the user. The method includes implementing a re-allocation instruction at the first S-CSCF. The reallocation instruction includes criteria for de-allocation of the user from the first S-CSCF. The S-CSCF determines if the criteria are met; and if the criteria are met, de-allocates the user.

Abstract: A method of handling SIP requests received by an IP Multimedia Subsystem network. The method comprises determining whether or not the SIP destination identity is within a range of identities owned by an operator of the network but is currently unallocated to a subscriber or service of the network and, if yes, routing the message to one or more SIP application servers within the network and implementing service logic at the application server(s) specific to a network owned but unallocated SIP identity.

Abstract: A Home Subscriber Server for handling IP Multimedia Subsystem subscriptions comprises means for maintaining associations between public user identities and Service Profiles, where two or more public user identities can be associated with a common Service Profile, and means for identifying to a network node all public user identities that are associated with a common Service Profile.

Abstract: The invention relates to a method of notifying an Application Function (AF) in a communications network of resource restrictions relating to a communication session. The network includes a Policy and Charging Rules Function (PCRF) for authorizing and controlling flows of data in the session. In the method the AF sends an authorization request to the PCRF for establishing the communication session. The authorization request includes an indication that the AF is to be notified of resource restrictions for the data flows in the session. The PCRF notifies the AF of the resource restrictions.

Abstract: A Home Subscriber Server for handling IP Multimedia Subsystem subscriptions comprises means for maintaining associations between public user identities and Service Profiles, where two or more public user identities can be associated with a common Service Profile, and means for identifying to a network node all public user identities that are associated with a common Service Profile.

Abstract: A server, computer readable medium and method for accessing buddy data related to a first user (presentity) that is connected to a communication network that includes a server, the data being accessed by a second user (watcher) connected to the communication network. The method including storing, at a server, information associated with a plurality of users associated with the presentity as the buddy data, receiving, at the server, a request from a watcher for buddy data of the presentity, authorizing, at least in part by the server, the request for buddy data, and transmitting, by the server, the buddy information to the watcher.

Abstract: A protocol conversion gateway and a method therein for enabling a client, which client does not support a Session Initiation Protocol (SIP) transport protocol, to communicate with a SIP proxy are provided. The method comprises receiving a first SIP message, over a non-standard SIP transport protocol, from the client. The method further comprises inserting a SIP address of the protocol conversion gateway in at least one header of the received SIP message, and sending the SIP message to the SIP proxy over a standard SIP transport protocol.

Abstract: A method is provided for facilitating recovery from the failure of a P-CSCF within an IP multimedia Subsystem network. A gateway, such as a GGSN, monitors signals arriving at the gateway from the P-CSCF and provides an indication if the monitored signals become unacceptable, for example because of an interruption in the signals. The gateway responds by signalling the unavailability of the P-CSCF to user equipment, which was associated with the P-CSCF during a previous registration with the IMS network. In response, for example, the user equipment affected by the failure may request re-registration with the IMS network using a different available P-CSCF.

Abstract: An originating P-CSCF node receives a SIP INVITE request from first user equipment (UE) that originates a call to a second UE. If a relay candidate address for the first UE is not present in the SIP INVITE request, the SIP INVITE request is modified to include a first address provided by an originating IMS-AGW node as a relay candidate for the first UE and forwarded to the second UE. The originating P-CSDF node receives a SIP INVITE response message from the second UE in response to the SIP INVITE request. If a relay candidate address for the second UE is not present in the SIP INVITE response, the SIP invite response is modified to include a second address provided by an originating IMS-AGW node as a relay candidate for the second UE and forwarded t the first UE. The address information is used by both UEs in ICE operations.

Abstract: A method of registering or deregistering a user to or from an IP Multimedia Subsystem (IMS) network. A SIP Application Server (SIP-AS) performs a registration or deregistration with the IMS network on a user's behalf. The registration or deregistration is performed over one of the following interfaces: a Service Control Interface (ISC) with a Serving Call State Control Function (S-CSCF), a Gm interface with a Proxy CSCF (P-CSCF), or an Ma interface with an Interrogating CSCF (I-CSCF).

Abstract: In one aspect, the invention provides a method, and associated apparatus for re-registering a contact address of a user of an IP Multimedia Subsystem, IMS, network. A request for re-registration of the contact address is received at a Serving-Call Session Control Function, S-CSCF, node serving the user. After a determination that the S-CSCF has no stored information relating to the contact address, a request is sent to a Home Subscriber Server, HSS, of the user to register the contact address information. The HSS detects if the contact address information relating to the user has already been backed-up by the HSS, and notifies the node serving the user of registered contact address information backed-up by the HSS. Another aspect provides a method and associated apparatus for de-registering a registered contact address of a user of an IP Multimedia Subsystem, IMS, network.

Abstract: A Home Subscriber Server for handling IP Multimedia Subsystem subscriptions comprises means for maintaining associations between public user identities and Service Profiles, where two or more public user identities can be associated with a common Service Profile, and means for identifying to a network node all public user identities that are associated with a common Service Profile.

Abstract: A Home Subscriber Server for handling IP Multimedia Subsystem subscriptions comprises means for maintaining associations between public user identities and Service Profiles, where two or more public user identities can be associated with a common Service Profile, and means for identifying to a network node all public user identities that are associated with a common Service Profile.

Abstract: A method of enabling users of a third party Internet service, who are not necessarily subscribers of an IP Multimedia Subsystem, IMS, network, to access services provided by the IMS network. The method comprises registering a user with said third party Internet service via the Internet using an Internet service identity of the user, and sending to the user, from said third party Internet service and via the Internet, IMS network access information. The access information is then used to register the user with the IMS network, wherein, following IMS registration, the user is able to access IMS network services.

Abstract: A method and apparatus for establishing a communication session in an IMS Centralized Services communication network. A Service Centralization and Continuity Application Server (SCC AS) receives a request from an originating device to establish a session with a target device. The request includes a plurality of codec identifiers that could be used by the originating device. The SCC AS sends a second request to establish the session to the target device. The SCC AS subsequently receives, from an intermediate node between the SCC AS and the target device, an invite message. The invite message includes an indication that a codec identifier has been selected from the plurality of codec identifiers. The SCC AS then sends a message to the intermediate node instructing the intermediate node to establish the session.

Abstract: A method is disclosed for use by an Interrogating Call/Session Control Function (I-CSCF) of an IP Multimedia Subsystem (IMS). In the method, a Session Initiation Protocol (SIP) message is received by the I-CSCF, which the I-CSCF attempts to forward to a Serving Call/Session Control Function (S-CSCF) of the IMS assigned to provide services to a user. If the attempt is determined to have failed, the I-CSCF sends a message to a Home Subscriber Server (HSS) of the IMS to request capabilities information for selecting a S-CSCF, the request message also providing first information relating to the status of the assigned S-CSCF. On receipt of the capabilities information at the I-CSCF from the HSS, the I-CSCF selects a replacement S-CSCF to provide services to the user. Related methods are also disclosed for use by the HSS and S-CSCF.