Abstract: A method implemented by a first network node in a communication network is provided. The method comprises: receiving a first subscription for subscribing a first User Equipment UE reachability event of a UE from an event subscriber, wherein the first subscription comprises a first indicator for indicating whether the first UE reachability event is to be reported in a direct mode or an indirect mode; sending a second subscription for subscribing a second UE reachability event to a second network node that is registered in the first network node, the second subscription comprises a second indicator for indicating that the first UE reachability event is to be directly or indirectly reported to the event subscriber according to the first indicator; and sending a first UE reachability report to the event subscriber.

Abstract: A method for network function discovery in a communication network is provided. The method includes receiving a discovery request from a first network function NF to request one or more NF instance of a first group type for a first subscriber. The discovery request may include a first group type identifier of the first group type. The method may further include determining one or more group identifier for one or more groups of NF instances managing the first subscriber. The one or more groups of NF instances are of the first group type and one or more other group types. The method may further include sending a discovery response to the first network function, including the one or more group identifiers and addressing information to reach the one or more groups of NF instances.

Abstract: A method for updating a location of a User Equipment, UE, when said UE moves from a first type of telecommunication network to a second type of telecommunication network, wherein said method comprises the steps of: receiving, by a user subscription node comprised by said second type of telecommunication network, an indication that said UE has requested registration to said second type of telecommunication network; determining, by said user subscription node comprised by said second type of telecommunication network, that said UE is registered in said first type of telecommunication network; transmitting, by said user subscription node comprised by said second type of telecommunication network, a location removal message to a user subscription node comprised by said first type of telecommunication network for removing location information relating to said UE.

Abstract: A method for updating a location of a User Equipment, UE, when said UE moves from a first type of telecommunication network to a second type of telecommunication network, wherein said method comprises the steps of: receiving, by a user subscription node comprised by said second type of telecommunication network, an indication that said UE has requested registration to said second type of telecommunication network; determining, by said user subscription node comprised by said second type of telecommunication network, that said UE is registered in said first type of telecommunication network; transmitting, by said user subscription node comprised by said second type of telecommunication network, a location removal message to a user subscription node comprised by said first type of telecommunication network for removing location information relating to said UE.

Abstract: A method and a node for storing subscription-related information and a method carried out in a node including a call session control function or applications server function and a corresponding node. There is a need to diminish signaling load in an IMS and/or shorten signaling time, particularly when updating user profiles in respect to service profiles. This is addressed by a method including the steps of receiving a request message identifying a user; determining whether the received request message comprises an indication of support of a user type associated with the user, the user type indicating that the user shares a certain user profile with other users; and storing for the user an attribute associated with the user type, which attribute is common for a plurality of users all associated with the same user type, if the received request message comprises the indication of support of the user type.

Abstract: There is provided a method of processing an IMS session originated by a UE after restart of a S-CSCF that was previously assigned to a user of the UE during registration with the IMS, when a further S-CSCF is currently assigned to the user. The method comprises, at a HSS, receiving a request to register a user identity of the user from the previously assigned S-CSCF, determining that the previously assigned S-CSCF is not the same as a S-CSCF currently assigned to the user, determining if IMS restoration procedures are supported for the UE, and, if IMS restoration procedures are not supported for the UE, sending a response to the previously assigned S-CSCF, the response identifying the further S-CSCF currently assigned to the user.

Abstract: A subscriber server routes a terminating call in a network that includes a circuit switched (CS) network, a packet switched (PS) network, and an IP Multimedia Subsystem (IMS). The server receives a request for routing information in relation to the terminating call from a CS node in the CS network. A determination is made at server based on whether a UE associated with the terminating call is registered in the IMS and the UE has access to the PS network. The server instructs the CS node to route the terminating call in the CS network when the UE is not registered in the IMS or when the UE does not have access to the PS network. The server instructs the CS node to send the terminating call to the IMS for handling when the UE is registered in the IMS and when the UE has access to the PS network.

Abstract: According to a first aspect there is provided a method of processing an IP Multimedia Subsystem (IMS) session originated by a User Equipment (UE) after failure of a Serving Call Session Control Function (S-CSCF) that was previously assigned to a user of the UE during registration with the IMS. The method comprises, at a Proxy Call Session Control Function (P-CSCF), upon determining that the P-CSCF is unable to forward a session establishment request for the session to the previously assigned S-CSCF, selecting an alternative S-CSCF from a S-CSCF pool, and sending the session establishment request for the session to the alternative S-CSCF.

Abstract: There is provided a method of processing an IMS session originated by a UE after restart of a S-CSCF that was previously assigned to a user of the UE during registration with the IMS, when a further S-CSCF is currently assigned to the user. The method comprises, at a HSS, receiving a request to register a user identity of the user from the previously assigned S-CSCF, determining that the previously assigned S-CSCF is not the same as a S-CSCF currently assigned to the user, determining if IMS restoration procedures are supported for the UE, and, if IMS restoration procedures are not supported for the UE, sending a response to the previously assigned S-CSCF, the response identifying the further S-CSCF currently assigned to the user.

Abstract: The present invention faces the issue of UE enabled to communicate with an IP Multimedia Subsystem following protocol versions older than Release 9, and provides for an alternative P-CSCF restoration procedure.

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.

Abstract: Methods and apparatuses for performing domain resolution prior to dispatching a request. A request from an Application Server (AS) is received. The AS and a network node are present in a first network domain. At least one target network domain is determined based on at least one domain indicator in the request. The domain indicator being associated with at least a part of the request, wherein the target network domain is one of: the first network domain and a second network domain. Then, the at least part of the request is dispatched, to at least one subscriber server present in the determined target network domain(s).

Abstract: A subscriber server routes a terminating call in a network that includes a circuit switched (CS) network, a packet switched (PS) network, and an IP Multimedia Subsystem (IMS). The server receives a request for routing information in relation to the terminating call from a CS node in the CS network. A determination is made at server based on whether a UE associated with the terminating call is registered in the IMS and the UE has access to the PS network. The server instructs the CS node to route the terminating call in the CS network when the UE is not registered in the IMS or when the UE does not have access to the PS network. The server instructs the CS node to send the terminating call to the IMS for handling when the UE is registered in the IMS and when the UE has access to the PS network.

Abstract: The present invention is aimed to provide means and methods for recovery of an IP Multimedia Subsystem ‘IMS’ where a Home Subscriber Server ‘HSS’ holding subscriber data for subscribers of the IMS has suffered a restart. A first method of recovery is applied after detecting a HSS restart, and as receiving a registration from a given subscriber or an invitation to communicate with a given subscriber from another subscriber. A second method of recovery is applied after detecting a HSS restart, and as receiving a request from a given subscriber at a S-CSCF previously assigned for serving the given subscriber in the IMS.

Abstract: A generic method is described for storing data in the HSS (2) by the S-CSCF (1) of an IMS. When a SIP message containing new information relating to an IMPI/IMPU pair is received by the S-CSCF (1), a data package is created for storage at the HSS (2), containing the new information. An SAR command is sent to the HSS (2) containing an AVP including an instruction to the HSS (2) and the new data package. In one aspect a unique data package is controlled by the S-CSCF (1). When new information relating to the IMPI/IMPU is received in a SIP message, this is added to any previously sent data package to create a new data package. In another aspect the HSS (2) controls a unique data package, returning the data package to the S-CSCF (1) to be amended if necessary. In another aspect separate data packages are used.

Abstract: Methods and systems are provided to reduce service delays in wireless communications networks. A method for gathering information associated with a user equipment (UE) at a node which is a part of a mobile communication network, the method includes: receiving a message at the node; and prefetching information associated with the UE upon receipt of the message, wherein prefetching includes transmitting a request for the information associated with the UE and receiving a response to the request for the information associated with the UE.

Abstract: A generic method is described for storing data in the HSS (2) by the S-CSCF (1) of an IMS. When a SIP message containing new information relating to an IMPI/IMPU pair is received by the S-CSCF (1), a data package is created for storage at the HSS (2), containing the new information. An SAR command is sent to the HSS (2) containing an AVP including an instruction to the HSS (2) and the new data package. In one aspect a unique data package is controlled by the S-CSCF (1). When new information relating to the IMPI/IMPU is received in a SIP message, this is added to any previously sent data package to create a new data package. In another aspect the HSS (2) controls a unique data package, returning the data package to the S-CSCF (1) to be amended if necessary. In another aspect separate data packages are used.

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.

Abstract: The present invention is aimed to provide means and methods for recovery of an IP Multimedia Subsystem ‘IMS’ where a Home Subscriber Server ‘HSS’ holding subscriber data for subscribers of the IMS has suffered a restart. A first method of recovery is applied after detecting a HSS restart, and as receiving a registration from a given subscriber or an invitation to communicate with a given subscriber from another subscriber. A second method of recovery is applied after detecting a HSS restart, and as receiving a request from a given subscriber at a S-CSCF previously assigned for serving the given subscriber in the IMS.

Abstract: A method is disclosed for use by an Interrogating Call/Session Control Function (I-CSCF) of an IP Multimedia Subsystem (IMS). The method comprises, in response to receipt of a Session Initiation Protocol (SIP) message, requesting capabilities information relating to a user from a Home Subscriber Server (HSS) of the IMS. On receipt of the capabilities information from the HSS, a primary and a secondary Serving Call/Session Control Function (S-CSCF) of the IMS are selected to provide services to the user. In one embodiment, the I-CSCF attempts to forward the SIP message to the primary S-CSCF with information relating to the secondary S-CSCF, such that the information can be provided subsequently to the HSS. If the attempt is determined to have failed, the SIP message can be forwarded to the secondary S-CSCF instead. Methods are also disclosed for use by the S-CSCF and the HSS.