Title of Invention	METHOD AND GATEWAY FOR CONNECTING IP COMMUNICATION ENTITES VIA A RESIDENTIAL GATEWAY
Abstract	The invention concerns a method for connection to IP communication entities (Expu,EyPu) via a residential gateway (Pz). It consists in registering (A) the public identity (pu) of each connected terminal associated with the network address (z) of the residential gateway, so that any message should be addressed to said residential gateway (Pz) and in transferring (B) said message to all the IP communication entities connected to the residential gateway (Pz) thus permitting each of the latter to filter (C) the message and to determine whether the message is addressed to a public identity which is assigned thereto. The invention is applicable to IP terminals managed in accordance with SIP or H323 protocol.

Title of Invention

METHOD AND GATEWAY FOR CONNECTING IP COMMUNICATION ENTITES VIA A RESIDENTIAL GATEWAY

Abstract

The invention concerns a method for connection to IP communication entities (Expu,EyPu) via a residential gateway (Pz). It consists in registering (A) the public identity (pu) of each connected terminal associated with the network address (z) of the residential gateway, so that any message should be addressed to said residential gateway (Pz) and in transferring (B) said message to all the IP communication entities connected to the residential gateway (Pz) thus permitting each of the latter to filter (C) the message and to determine whether the message is addressed to a public identity which is assigned thereto. The invention is applicable to IP terminals managed in accordance with SIP or H323 protocol.

Full Text	METHOD AND GATEWAY FOR CONNECTING IP COMMUNICATION ENTITES VIA A RESIDENTIAL GATEWAY The invention relates to a method and a system for linking SIP terminals, or terminals that are able to implement a call setup protocol, for example the SIP protocol (for Session Initiation Protocol), to residential gateways. From the outset, it will be noted that the expression "residential gateway" is understood to refer to a client gateway, that is to say a gateway situated user side, in contradistinction to an item of network equipment situated in the network under the control of the operator. It may, by way of nonlimiting examples, be a gateway for domestic use within a residence or a gateway for professional use within a company. In a general way, it is a gateway for client use. Numerous offers of telephone facilities over the IP network are, at the present time, based on domestic installations composed of a residential gateway linking one or more mono or multimedia terminals, such as visiophone analog telephones, personal computers, digital televisions for example. The aforesaid residential gateways are also referred, to as intelligent residential gateways, since they make it possible, in fact, to link various categories of networks. The present invention is aimed more particularly at the functionalities of residential gateways intended for real time electronic communication services, such as VoIP telephony (voice over IP) , video-telephony for example. The aforesaid residential gateways communicate with the operator's network by virtue of a call control protocol whose objective is the creation of a VoIP type communication context between two IP terminations. The objective of the aforesaid SIP protocol defined by the IETF (Internet Engineering Task Force) is to allow setup, modification and termination of multimedia sessions in an IP network or within the framework of architectures for controlling networks based on IP transport. The role of residential gateways in exchanges of SIP signaling depends on the type of terminal linked up: when the terminal linked up is not an IP terminal such as an analog, RNIS, Bluetooth, DECT or other terminal, the gateway plays the role of SIP termination by performing the translation between the SIP signaling exchanged with the network and the signaling exchanged with the terminal. This situation corresponds to the case of the "VEG" VoIP Embedded Gateway function represented in Figure la, this type of terminal being referred to as a non-IP terminal in the present patent application; - when the terminal linked up is of IP type, any SIP terminal, the residential gateway behaves as a simple router and steers the SIP messages to the terminal or terminals concerned. The latter then play the role of termination for the SIP protocol. Current residential gateways may operate according to two operative modes making it possible to manage multiline connection, such as represented in Figure la. The SIP protocol comprises a registration phase, termed the REGISTER phase, the object of which is the creation, in the network, of an association between the public identity of a user, on the basis of which the latter can be contacted, telephone number or SIP Universal Resource Identifier URI, and the network address or addresses of the terminals enabling the network to contact them. The aforesaid association is stored in a location database. The first operative mode represented in Figure lb, consists in declaring each terminal, separately in relation to the network, situated or not situated behind the same residential gateway, even when these terminals share one and the same public identity. The network then acts as if the declared terminals were not hosted by the same residential gateway. In this multiline operative mode during the registration phase, each declared terminal announces its network address, IP address + port pair, and its public identity, telephone number. The corresponding association is stored in a database so as to be interrogated by a specific item of equipment, such as an SIP proxy, handling the trunking of the incoming calls to their final destination(s). Each terminal has a priori a different network address from the others, independently of the fact that it does or does not share its public identity with another terminal. Within the framework of the aforesaid operative mode, one and the same public identity thus points to several network addresses. With each incoming call to a given public number, on receipt of a call setup message, the SIP proxy forwards this message to each of the SIP destinations through interrogation of the database. In this automatic call distribution system referred to as "forking", the residential gateway merely routes the incoming IP packets, as would a simple IP router. A second operative mode, represented in Figure lc, consists in incorporating into the residential gateway an application package processing allowing the gateway to offer the network a single physical interface by handling the final trunking of the incoming calls to the appropriate SIP destination or destinations, that is to say the terminals. During the registration phase, the residential gateway sends registration messages for the account of the terminals that it links. Several modes of implementation are conceivable, depending on whether the terminals send or do not send any registration messages. Under the first assumption, the residential gateway intercepts the "REGISTER" registration messages sent by the SIP terminals and modifies them so as to appear as the single SIP destination for the whole set of numbers attached to the terminals that it connects. Furthermore, the residential gateway stores in an internal database the correspondence between the public identity allocated to the terminal and the associated network address. Under the second assumption, the residential gateway determines on the basis of configuration data the associations between network addresses of the terminals and corresponding allocated public identities, then sends one or more "REGISTER" registration messages on the basis of these associations, here again passing itself off as the single SIP destination to be contacted. On receipt by its internal SIP processing logic of an "INVITE" call setup message, the residential gateway determines the public identity targeted by the call, by inspecting the header of the SIP message "To", then interrogates its internal database, so as to retrieve the SIP terminal or terminals concerned so as to forward the "INVITE" call setup message to them. The first and second operative modes of the prior art exhibit the drawbacks hereinafter. The solution according to the first operative mode according to the "forking" technique requires the storage at each instant by the network of the linkup topology information for all the residential gateways. In addition to the aforesaid storage, this operative mode leads to the generation of more signaling than is necessary. Specifically, the operations of registering/de-registering the terminals lead systematically to exchanges of registration messages. Moreover, during an incoming call, a call setup request must be sent to each of the terminals. The network must then take on board the cancellation of the transactions with no response by the targeted terminal. The solution according to the second operative mode, palliative processing incorporated into the gateway, exhibits the drawback of adding non-trivial appliccition procedures to the residential gateway, as well as an internal mini-database. This solution therefore appears to be prejudicial to the performance of the residential gateway. The subject of the present invention is to remedy the drawbacks of the aforesaid prior art solutions. A subject of the present invention is the implementation of a method and of a residential gateway that may suit all the linkup configurations and terminals behind a residential gateway, in particular, a public identity per terminal, a public identity shared by several terminals, several public identities attached to the same terminal. Another subject of the present invention is furthermore the implementation of a method and of a residential gateway not requiring any incorporation of application into the residential gateway, the latter not having to be aware of the correspondence between the tesrminals that it links up and their associated public identities, so as to reduce to a situation comparable to the mode of network handling via "forking". Another subject of the present invention is also the implementation of a method and of a residential gateway in which the management of the terminal association or terminal address and public identity is also no longer performed by the network, which, in particular, does not have to be aware of the number of terminals associated with a public identity and of their respective network address (addresses), the network having to be aware only of the correspondence between the public identity or identities and the network address of the residential gateway, so as to reduce to a situation comparable with the operative mode with SIP application package processing incorporated into the gateway. This exhibits the advantage of not complicating the processing of the incoming calls destined for a number corresponding to several terminals situated behind one and the same residential gateway. Specifically, in such linkup configurations, a single call setup request is sent to the gateway, rather than one per terminal corresponding to the requested number. In particular, a subject of the present invention is the implementation of a residential gateway operating mechanism making it possible to process complex linkup configurations, in particular suited to the linking up of terminals sharing one and the same call number, a residential gateway in accordance with the subject of the invention being dubbed "multi-line" when, linking up several terminals, one and the same public identity is associated with them, a telephone number corresponding to a particular case of public identity. Another subject of the present invention is, finally, the implementation of a method and of a residential gateway operating with a call control signaling protocol based on an IP technology, in particular, the SIP protocol defined by RFC 3261, the H.323 protocol or ultimately any other call control protocol of the same type. Another subject of the present invention is also the implementation of a method and of a residential gateway that may be implemented not only for SIP terminals, but also for any termination point of SIP type internal to the residential gateway, in fact representing an interface to a non-IP terminal, the processings necessary for such a transition being performed by the corresponding VEG module internal to the residential gateway. The method for linking to an IP network, by way of a residential gateway, a plurality of IP communication entities to which are allocated respective public identities and which are able to implement a call control protocol, said IP communication entities, internal or external to the gateway, being connected to the latter, which is the subject of the invention, is noteworthy in that it comprises a prior step of registering the respective public identities of said IP communication entities, each entity public identity being associated during registration with a network address of the gateway, in such a way that a message according to the call control protocol and addressed to said public identity is transmitted to the gateway. In the event of reception by the gateway of a message according to the call control protocol, a step of transferring said message from the gateway to all the connected entities, and after receipt of the message by a connected entity, a step of filtering of the message by said entity, in the course of which the entity determines whether the message is addressed to the public identity allocated to it. The method which is the subject of the invention is furthermore noteworthy in that, in the case of a message according to the SIP protocol, the step of filtering the message is carried out on the basis of the content of one at least of the fields of the group comprising the field identifying the recipient of the message and the field defining the unit handling the processing of the message. The residential gateway for linking to an IP network a plurality of IP communication entities that are able to implement a call control protocol, this residential gateway connected to the IP network having available an IP network address, which is the subject of the invention, is noteworthy in that it comprises at least one module for transferring to all the IP communication entities connected to it messages according to the call control protocol, that are received by said gateway and addressed to a public identity associated with one at least of the IP communication entities connected to the gateway. The IP communication entity to which a public identity, which is the subject of the invention, is allocated, is noteworthy in that it includes at least one message filtering module designed to determine whether a message received is addressed to the public identity allocated thereto. The IP communication entity, is furthermore noteworthy in that it is able to be integrated into a residential gateway and that it comprises means for communicating with a non-IP external communication terminal. The IP communication entity, which is the subject of the invention is finally noteworthy in that the message filtering module is designed, on receipt of a message, to analyze at least one of the fields of the group comprising a field identifying the recipient of the message and a field defining the entity handling the processing of the message, said fields being contained in the message received. The method, the residential gateway and the communication entity IP, which are the subjects of the present invention, find application to the management of the linking up of IP terminals and non-IP terminals having a public identity and triggering a call control protocol, such as domestic terminals or of a mono or multimedia local network for analog telephones, visiophones, PC personal computers, digital televisions or others that can have one and the same public identity. They will be better understood on reading the description and observing the drawings hereinafter in which, in addition to Figures la with lc relating to the prior art: - Figure 2a represents, by way of illustration, a flowchart of the essential steps for implementing the method which is the subject of the present invention; - Figure 2b represents by way of illustration a flowchart according to a nonlimiting preferential mode for implementing the step of transferring the residential gateway to all the IP communication entities on the basis of the residential gateway; - Figure 2c represents, by way of illustration, an exemplary implementation of the method for linking IP communication entities to an IP network for an installation comprising a residential gateway connected to an SIP proxy and to two IP communication entities as well as to a non-IP terminal, such as a fixed telephone handset connected to an internal IP communication entity integrated into the residential gateway, in accordance with the subject of the present invention. The method for linking to an IP network IP communication entities that are able to implement a call control protocol, by way of a local gateway, which is the subject of the invention, will now be described in a detailed manner. The IP communication entities are internal or external to the local gateway. In the particular, nonlimiting, example of the description, the call control protocol is the SIP protocol and the local gateway is a residential gateway, situated in a user's residence. In the particular example described for the implementation of the method which is the subject of the invention, we consider: - the residential gateway, denoted Pz, z denoting the IP address of the residential gateway, - two IP communication entities consisting of IP terminals, external to the gateway Pz and connected to the latter, and denoted Ex,pu where x denotes the IP address of the IP entity considered and pu the public identity associated with the IP entity considered, - an IP communication entity consisting of a VEG (for VoIP Embedded Gateway) module, internal to the gateway Pz and connected to the latter, and denoted Ey,pu where y denotes the IP address of the entity considered and pu the public identity associated with the IP entity considered. Of course, the invention can be applied to any other system of this type comprising at least one residential gateway and a plurality of IP communication entities, internal or external to the gateway and connected to the latter. As will be observed in Figure 2a, the linkup method which is the subject of the invention consists, in a step A, in registering the public identity of each connected communication entity, this public identity being associated with the network address z of the gateway Pz during registration. In Figure 2a, this operation is denoted: registration {{pu}tpu, z} The aforesaid registration is performed in such a way that any message according to the call control protocol designated hereinafter, message denoted M(pu), be it a call setup request or any other message transmitted according to the call control protocol, to this public identity pu is addressed to the residential gateway Pz. Step A, following the reception of this message M(pu) by the residential gateway, is followed by a step B of transferring the message M(pu) to all the IP communication entities, internal Ex,pu or external Ey,pu to the gateway Pz and connected to the latter, from the residential gateway Pz. In step B of Figure 2a, the transfer operation is denoted: Transfer M(pu) - Ex,pu; Ey,pu. The aforesaid transfer operation B allows each of the IP communication entities internal EPx,pu or external EPy,Pu to the gateway Pz to thereafter filter the message M(pu), so as to determine whether or not this message is addressed to a public identity allocated to it. In a general way, it is considered that the linkup process;, in accordance with the linkup method which is the subject of the invention, consists at least of steps A, B, described with Figure 2a. However, this linkup process for executing the linkup method which is the subject of the invention is then followed at the level of each IP communication entity EX/PU, Ey,pu by a filtering process in step C represented in the aforesaid Figure 2a. As will be observed in Figure 2a, for a message M(pu) each internal or external IP communication entity can undertake, in a step Co, a verification by comparing the public identity called in the message M(pu) with its own public identity allocated to it. This step is represented in step Co of Figure 2a by the test relation: pu = pu,x; pu,y ? Through the aforesaid test, it is understood that each internal or external IP communication entity that is a recipient of the message M(pu) undertakes an identification in the aforesaid step C0. On a negative response to the test of the aforesaid step Co, the internal or external IP communication entity considered in step C2 ignores the message. Conversely on a positive response to the test of step C0, that is to say in the event of identity between the public identity called in the message received and the public identity allocated to the internal or external IP communication entity considered, step C0 is followed by a step C1 of processing the aforesaid message M(pu). In a specific manner, it is indicated that the process for filtering the messages received, these messages having been transmitted according to the SIP protocol, consists in determining, for each message received by an IP communication entity, whether the message: is addressed to the public identity allocated to this IP communication entity either on the basis of the field identifying the recipient of the message, that is to say the field denoted by field "To" according to the SIP protocol, or on the basis of the field defining the unit handling the processing of the message, that is to say on the basis of the field denoted "REQUEST URI" according to the SIP protocol. When the internal or external IP communication entity EX/PU Ey,pu is recognized to be a recipient for example of a request, the latter performs the processing associated with the reception of the aforesaid request, this processing being able to consist for example in the fact of ringing on receipt of a call setup request, the ring occurring either at the level of the IP communication entity, or conversely at the level of the non-IP terminal when the latter is linked to an internal IP communication entity associated with it. Otherwise, as is represented in Figure 2a, the call setup request M(pu) is then ignored. More specifically, the transfer step B of Figure 2a, is executed by transferring the message M(pu) over the IP network to each of the external IP communication entities connected on the basis of the residential gateway Pz. Conversely, in the case where the gateway comprises and integrates internal IP communication entities to which non-IP terminals are linked, the residential gateway Pz forwards the aforesaid messages M(pu) to each of the corresponding internal modules VEG, as if it were in fact an IP terminal. The IP communication entity invoked then processes the message M(pu) in the same way as would an IP terminal. A more detailed description of the transmission operation B of Figure 2a will be now given in conjunction with Figure 2b, this transmission operation being performed at the level of the residential gateway Pz. In a general manner, it is indicated, by way of nonlimiting example, that the registration operation A can be performed by the network, this operation being described subsequently in the description. Under these conditions, the registration proper of the whole set of public identities denoted {{pu}tPu, z} associated with the network address z of the residential gateway Pz is available at the level of the aforesaid performed registration. More specifically, during the transmission of a call setup request M(pu), this request is transmitted by way of an item of network equipment ER formed by an SIP proxy when the SIP protocol is implemented, this item of network equipment ER being associated, inter alia with the gateway Pz and making it possible to manage this gateway Pz. With reference to Figure 2b, the item of network equipment ER proceeds on receipt of the message M(pu) to the recovery of the network address z of the residential gateway Pz by identifying the public identity called pu, on the basis of the registration previously mentioned, in sub-step B0 of Figure 2b. The item of network equipment ER then proceeds in sub-step B1 to the transmission to the residential gateway Pz of the message M(pu) at the address z which was recovered in the previous step B0. On receipt of the message M(pu) by the residential gateway Pz, the latter, in sub-step B2/ undertakes the transfer of the message M(pu) to the whole set of IP communication entities internal or external to the platform Pz and connected to the latter. A more detailed description of the operative mode of the linkup method, which is the subject of the invention, will be now given in conjunction with Figure 2c in a nonlimiting specific domestic configuration given solely by way of example. The initial domestic configuration represented in Figure 2c is considered in particular, in which the gateway Pz whose IP network address is z = "1.1.1.4" links two terminals associated with one and the same public identity consisting of a telephone number + 33 14 52 94 814. The first terminal, terminal of non-IP type, is represented by an internal VEG module, constituting an internal IP communication entity having an IP address y = "10.1.1.1". The second terminal of IP communication entity type external to the gateway Pz and linked to the latter has a network address x = "10.1.1.2". As furthermore represented in Figure 2c, the gateway Pz also links a third terminal, of external IP communication entity type, whose public identity is different + 33 14 52 96 496 and having a network address x = "10.1.1.3". In accordance with a noteworthy aspect of the method which is the subject of the invention, step A consisting in performing the registration can advantageously include the creation of a location database DB of the association between the set of first and second aforesaid public identities and of the IP address of the residential gateway Pz. In Figure 2c it is understood that the aforesaid registration comprises the public identities + 33 14 52 94 814 and + 33 14 52 96 496 referred to as numbers associated with the target, that is to say with the IP address of the residential gateway z = "1.1.1.4". For the implementation of the aforesaid registration several operative modes can be performed. The aforesaid registration can, for example, be configured by default in the location database DB upon the user's subscription to the telephone service. This registration can also be dynamic according to the mechanism defined by the standard RFC32 61 of the SIP protocol (for Session Initiation Protocol). Under this assumption each terminal transmits a "REGISTER" request to the network, the contact address contained in these request messages corresponding to the contact address of the residential gateway. In the example given in conjunction with Figure 2c, during a call phase for example, the item of network equipment ER responsible for the residential gateway Pz receives a message constituting a request to set up a call M(pu) destined for a public identity, the number + 33 14 52 94 814 previously described. The item of network equipment ER formed by the SIP proxy recovers from the location database DB the network address z associated with this public identity and retransmits the call setup message to this address z. The residential gateway Pz receiving this message forwards it immediately to the internal or external IP communication SIP entities that it links. The IP terminals and the IP termination then examine the SIP field "To" of this request, that is to say the field containing the public identity of the requested terminal, so as to determine whether this request is or is not intended for them. The two SIP external or internal IP communication entities responding to the number + 33 14 52 94 814 then deduce from this analysis that the request is intended for them and ring, while the IP communication entity associated with the number + 33 14 52 96 496 ignores the aforesaid request message. The rest of the call setup is performed as defined in the standard RFC3261. The chronology of the messages transmitted between the network entity ER formed by the SIP proxy, the residential gateway Pz and each of the IP communication entities represented in Figure 2c is as follows: 1: INVITE; To + 33 14 52 94 814 2: DB Interrogation 3: INVITE; 1.1.1.4; To + 33 14 52 94 814 4a: Redirection; 1.1.1.4; + 33 14 52 94 814 to VEG 4b: INVITE; 1.1.1.4; To + 33 14 52 94 814 to 10.1.1.2 4c: INVITE; 1.1.1.4; To + 33 14 52 96 496 to 10.1.1.3 A more detailed description of a residential gateway for linking to the IP network a plurality of internal or external IP communication entities that are able to implement a call control protocol, this residential gateway connected to the IP network having an IP address, in accordance with the subject of the present invention, will be now given in conjunction with Figure 2c. As represented in Figure 2c, the residential gateway Pz includes at least one transfer module denoted TM with the function of forwarding to all the IP communication entities, internal or external to the gateway Pz and connected to the latter, the messages received by the gateway Pz, and addressed to at least one among the plurality of public identities respectively associated with these connected IP communication entities. It is indicated that the aforesaid transfer module TM can consist of a software module making it possible to simply ensure the redirection of the message M(pu) to any internal IP communication entity, such as a VEG module associated with a non-IP terminal, as previously described in conjunction with Figure 2c, or, conversely, the transmission by network, that is to say by transmission of an "INVITE" message within the framework of the SIP protocol to any external IP communication entity connected to the aforesaid residential gateway Pz. These "INVITE" messages are messages 4b and 4c of the figure previously mentioned in the description. The external respectively internal IP communication entity having a public identity and an IP address, in accordance with the subject of the present invention, is noteworthy in that each of these latter includes a module FM for filtering the messages M(pu) received, whose function is to determine, for each message received, whether this message is addressed to the public identity allocated to the IP communication entity considered. This filtering module can consist of a software module installed directly in the IP communication entity considered and in particular in the VEG module integrated into the residential gateway Pz. When the filtering module FM is integrated into the VEG module, that is to say into the IP communication entity internal to the gateway Pz, this IP communication entity advantageously comprises a module for communicating with a non-IP terminal external to the gateway Pz. The role of this communication module is to ensure connection of the VEG module, internal to the gateway Pz, to the non-IP terminal, external to the gateway Pz, as well as communication between the VEG module and the non-IP terminal. As previously mentioned within the framework of the description of the method which is the subject of the invention, it is indicated that the filtering module FM executes an evaluation either of the field identifying the recipient of the message, or of the field defining the unit handling the processing of this message. As mentioned previously in the description, it is either the field "To" of the SIP messages or conversely the field defining the unit handling the processing for example the field comprising the network address "10.1.1.1" of the internal IP communication entity consisting of the VEG module integrated into the gateway Pz represented in Figure 2c, for the non-IP terminal associated with it. The invention also covers a computer program for a residential gateway comprising instructions able to control the transferring, by the gateway, of a message according to a call control protocol received by the gateway, to all the IP communication entities connected to it, when the program is executed by the gateway. This program can be stored in or transmitted by a data medium. The latter can be a hardware storage medium, for example a CD-ROM, a magnetic diskette or a hard disk, or else a transmissible medium such as an electrical, optical or radio signal. It is of course understood that the corresponding program product is then stored either by downloading or in any other way at the residential gateway Pz level and in particular in the transfer module TM represented in Figure 2c. The invention also covers a computer program for an IP communication entity, such as previously described, to which a public identity is allocated, comprising instructions for executing a filtering of the messages according to a call control protocol received by said entity so as to determine whether these messages are addressed to the public identity of said entity, when the program is executed by the IP communication entity. This program can be stored in or transmitted by a data medium. The latter can be a hardware storage medium, for example a CD-ROM, a magnetic diskette or a hard disk, or else a transmissible medium such as an electrical, optical or radio signal. In the preceding description, the messages are transmitted to the residential gateway according to the SIP protocol. The invention also applies to the transmission of messages according to the H323 protocol or according to any other call control protocol designed to be implemented by IP communication entities, connected to the IP network but each comprising a public identity which is allocated to them, and distinguishing between the concept of public identity and that of network address. To go back to the particular example of the H323 protocol, this protocol also envisages a registration phase making it possible to register in the network the correspondence between a user's public identity and the network address of his location point in the network. It therefore suffices to register, during this registration phase and via messages defined by the H323 protocol, the correspondence between the network address, in this instance the IP address, of the residential gateway and the respective public identities associated with the IP communication entities that it links. The role of the residential gateway is then to forward all the messages, in particular the SETUP call setup requests as defined by the H323 protocol, that it receives to all the H323 entities that it links. In the same way as in the case of the SIP protocol, each entity H323 is left to handle the operation of filtering the messages received so as to determine, for each message received, whether or not it is intended for the entity considered. CLAIMS 1. A method for linking to an IP network, by way of a residential gateway, a plurality of IP communication entities to which are allocated respective public identities and which are able to implement a call control protocol, said IP communication entities, internal or external to the gateway, being connected to the latter, characterized in that it comprises: - a prior step of registering the respective public identities of said IP communication entities, each entity public identity being associated during registration with a network address of the gateway, in such a way that a message according to the call control protocol and addressed to said public identity is transmitted to the gateway; - in the event of the receipt by the gateway of a message according to the call control protocol, a step of transferring said message from the gateway to all the connected entities; and - after receipt of the message by a connected entity, a step of filtering of the message by said entity, in the course of which the entity determines whether the message is addressed to the public identity allocated to it. 2. The method as claimed in claim 1, in which the call control protocol is one of the protocols of the group comprising the SIP protocol and the H323 protocol. 3. The method as claimed in claim 2, in which, in the case of a message according to the SIP protocol, the step of filtering the message is carried out on the basis of the content of one at least of the fields of the group comprising the field identifying the recipient of the message and the field defining the unit handling the processing of the message. 4. The method as claimed in one of claims 1 to 3, in which, in the case where during the filtering step, the IP communication entity determines that the message received is addressed to the public identity allocated to it, said entity executes a processing associated with the message. 5. The method as claimed in one of claims 1 to 4, in which, in the course of the prior registration step, the respective public identities of the connected entities and the network address of the associated gateway are registered in a location database, accessible to an item of routing network equipment associated with the gateway. 6. The method as claimed in claim 5, in which, in the event of reception by the item of routing network equipment of a message to set up a call according to the call control protocol, addressed to one of the entities registered in association with the network address of the gateway, the item of routing network equipment recovers from said database the network address of the gateway, on the basis of the public identity to which the message is addressed, then transmits the message to the gateway at said recovered network address. 7. A residential gateway for linking to an IP network a plurality of IP communication entities that are able to implement a call control protocol, the gateway connected to the IP network having available a network address, characterized in that it comprises a module for transferring to all the IP communication entities connected to it messages according to the call control protocol, that are received by said gateway and addressed to a public identity associated with one at least of the IP communication entities connected to the gateway. 8. An IP communication entity, to which a public identity is allocated, characterized in that it comprises a message filtering module, designed to determine whether a message received is addressed to the public identity allocated thereto. 9. The IP communication entity, as claimed in claim 8, characterized in that it is able to be integrated into a residential gateway and that it comprises means for communicating with a non-IP external communication terminal. 10. The IP communication entity, as claimed in one of claims 8 and 9, in which the message filtering module is designed, on receipt of a message, to analyze at least one of the fields of the group comprising a field identifying the recipient of the message and a field defining the entity handling the processing of the message, said fields being contained in the message received. 11. A computer program for a residential gateway, characterized in that it comprises instructions designed to control the transferring by the gateway of a message according to a call control protocol, received by said gateway, to all the IP communication entities connected to the gateway, when it is executed by the latter. 12. A computer program for an IP communication entity, to which a public identity is allocated, characterized in that it comprises instructions designed to control the filtering of a message according to a call control protocol, received by said entity, so as to determine whether said message receivec is addressed to the public identity which is allocated to the entity, when said program is executed by the latter. The invention concerns a method for connection to IP communication entities (Expu,EyPu) via a residential gateway (Pz). It consists in registering (A) the public identity (pu) of each connected terminal associated with the network address (z) of the residential gateway, so that any message should be addressed to said residential gateway (Pz) and in transferring (B) said message to all the IP communication entities connected to the residential gateway (Pz) thus permitting each of the latter to filter (C) the message and to determine whether the message is addressed to a public identity which is assigned thereto. The invention is applicable to IP terminals managed in accordance with SIP or H323 protocol.

Full Text

METHOD AND GATEWAY FOR CONNECTING IP COMMUNICATION
ENTITES VIA A RESIDENTIAL GATEWAY
The invention relates to a method and a system for
linking SIP terminals, or terminals that are able to
implement a call setup protocol, for example the SIP
protocol (for Session Initiation Protocol), to
residential gateways.
From the outset, it will be noted that the
expression "residential gateway" is understood to refer
to a client gateway, that is to say a gateway situated
user side, in contradistinction to an item of network
equipment situated in the network under the control of
the operator. It may, by way of nonlimiting examples,
be a gateway for domestic use within a residence or a
gateway for professional use within a company. In a
general way, it is a gateway for client use.
Numerous offers of telephone facilities over the
IP network are, at the present time, based on domestic
installations composed of a residential gateway linking
one or more mono or multimedia terminals, such as
visiophone analog telephones, personal computers,
digital televisions for example.
The aforesaid residential gateways are also
referred, to as intelligent residential gateways, since
they make it possible, in fact, to link various
categories of networks.
The present invention is aimed more particularly
at the functionalities of residential gateways intended
for real time electronic communication services, such
as VoIP telephony (voice over IP) , video-telephony for
example.
The aforesaid residential gateways communicate
with the operator's network by virtue of a call control
protocol whose objective is the creation of a VoIP type
communication context between two IP terminations. The
objective of the aforesaid SIP protocol defined by the
IETF (Internet Engineering Task Force) is to allow

setup, modification and termination of multimedia
sessions in an IP network or within the framework of
architectures for controlling networks based on IP
transport.
The role of residential gateways in exchanges of
SIP signaling depends on the type of terminal linked
up:
when the terminal linked up is not an IP
terminal such as an analog, RNIS, Bluetooth, DECT or
other terminal, the gateway plays the role of SIP
termination by performing the translation between the
SIP signaling exchanged with the network and the
signaling exchanged with the terminal. This situation
corresponds to the case of the "VEG" VoIP Embedded
Gateway function represented in Figure la, this type of
terminal being referred to as a non-IP terminal in the
present patent application;
- when the terminal linked up is of IP type, any
SIP terminal, the residential gateway behaves as a
simple router and steers the SIP messages to the
terminal or terminals concerned. The latter then play
the role of termination for the SIP protocol.
Current residential gateways may operate according
to two operative modes making it possible to manage
multiline connection, such as represented in Figure la.
The SIP protocol comprises a registration phase,
termed the REGISTER phase, the object of which is the
creation, in the network, of an association between the
public identity of a user, on the basis of which the
latter can be contacted, telephone number or SIP
Universal Resource Identifier URI, and the network
address or addresses of the terminals enabling the
network to contact them. The aforesaid association is
stored in a location database.
The first operative mode represented in Figure lb,
consists in declaring each terminal, separately in
relation to the network, situated or not situated
behind the same residential gateway, even when these

terminals share one and the same public identity. The
network then acts as if the declared terminals were not
hosted by the same residential gateway.
In this multiline operative mode during the
registration phase, each declared terminal announces
its network address, IP address + port pair, and its
public identity, telephone number. The corresponding
association is stored in a database so as to be
interrogated by a specific item of equipment, such as
an SIP proxy, handling the trunking of the incoming
calls to their final destination(s).
Each terminal has a priori a different network
address from the others, independently of the fact that
it does or does not share its public identity with
another terminal.
Within the framework of the aforesaid operative
mode, one and the same public identity thus points to
several network addresses. With each incoming call to a
given public number, on receipt of a call setup
message, the SIP proxy forwards this message to each of
the SIP destinations through interrogation of the
database. In this automatic call distribution system
referred to as "forking", the residential gateway
merely routes the incoming IP packets, as would a
simple IP router.
A second operative mode, represented in Figure lc,
consists in incorporating into the residential gateway
an application package processing allowing the gateway
to offer the network a single physical interface by
handling the final trunking of the incoming calls to
the appropriate SIP destination or destinations, that
is to say the terminals.
During the registration phase, the residential
gateway sends registration messages for the account of
the terminals that it links.
Several modes of implementation are conceivable,
depending on whether the terminals send or do not send
any registration messages.

Under the first assumption, the residential
gateway intercepts the "REGISTER" registration messages
sent by the SIP terminals and modifies them so as to
appear as the single SIP destination for the whole set
of numbers attached to the terminals that it connects.
Furthermore, the residential gateway stores in an
internal database the correspondence between the public
identity allocated to the terminal and the associated
network address.
Under the second assumption, the residential
gateway determines on the basis of configuration data
the associations between network addresses of the
terminals and corresponding allocated public
identities, then sends one or more "REGISTER"
registration messages on the basis of these
associations, here again passing itself off as the
single SIP destination to be contacted. On receipt by
its internal SIP processing logic of an "INVITE" call
setup message, the residential gateway determines the
public identity targeted by the call, by inspecting the
header of the SIP message "To", then interrogates its
internal database, so as to retrieve the SIP terminal
or terminals concerned so as to forward the "INVITE"
call setup message to them.
The first and second operative modes of the prior
art exhibit the drawbacks hereinafter.
The solution according to the first operative mode
according to the "forking" technique requires the
storage at each instant by the network of the linkup
topology information for all the residential gateways.
In addition to the aforesaid storage, this operative
mode leads to the generation of more signaling than is
necessary. Specifically, the operations of
registering/de-registering the terminals lead
systematically to exchanges of registration messages.
Moreover, during an incoming call, a call setup request
must be sent to each of the terminals. The network must

then take on board the cancellation of the transactions
with no response by the targeted terminal.
The solution according to the second operative
mode, palliative processing incorporated into the
gateway, exhibits the drawback of adding non-trivial
appliccition procedures to the residential gateway, as
well as an internal mini-database. This solution
therefore appears to be prejudicial to the performance
of the residential gateway.
The subject of the present invention is to remedy
the drawbacks of the aforesaid prior art solutions.
A subject of the present invention is the
implementation of a method and of a residential gateway
that may suit all the linkup configurations and
terminals behind a residential gateway, in particular,
a public identity per terminal, a public identity
shared by several terminals, several public identities
attached to the same terminal.
Another subject of the present invention is
furthermore the implementation of a method and of a
residential gateway not requiring any incorporation of
application into the residential gateway, the latter
not having to be aware of the correspondence between
the tesrminals that it links up and their associated
public identities, so as to reduce to a situation
comparable to the mode of network handling via
"forking".
Another subject of the present invention is also
the implementation of a method and of a residential
gateway in which the management of the terminal
association or terminal address and public identity is
also no longer performed by the network, which, in
particular, does not have to be aware of the number of
terminals associated with a public identity and of
their respective network address (addresses), the
network having to be aware only of the correspondence
between the public identity or identities and the
network address of the residential gateway, so as to

reduce to a situation comparable with the operative
mode with SIP application package processing
incorporated into the gateway. This exhibits the
advantage of not complicating the processing of the
incoming calls destined for a number corresponding to
several terminals situated behind one and the same
residential gateway.
Specifically, in such linkup configurations, a
single call setup request is sent to the gateway,
rather than one per terminal corresponding to the
requested number.
In particular, a subject of the present invention
is the implementation of a residential gateway
operating mechanism making it possible to process
complex linkup configurations, in particular suited to
the linking up of terminals sharing one and the same
call number, a residential gateway in accordance with
the subject of the invention being dubbed "multi-line"
when, linking up several terminals, one and the same
public identity is associated with them, a telephone
number corresponding to a particular case of public
identity.
Another subject of the present invention is,
finally, the implementation of a method and of a
residential gateway operating with a call control
signaling protocol based on an IP technology, in
particular, the SIP protocol defined by RFC 3261, the
H.323 protocol or ultimately any other call control
protocol of the same type.
Another subject of the present invention is also
the implementation of a method and of a residential
gateway that may be implemented not only for SIP
terminals, but also for any termination point of SIP
type internal to the residential gateway, in fact
representing an interface to a non-IP terminal, the
processings necessary for such a transition being
performed by the corresponding VEG module internal to
the residential gateway.

The method for linking to an IP network, by way of
a residential gateway, a plurality of IP communication
entities to which are allocated respective public
identities and which are able to implement a call
control protocol, said IP communication entities,
internal or external to the gateway, being connected to
the latter, which is the subject of the invention, is
noteworthy in that it comprises a prior step of
registering the respective public identities of said IP
communication entities, each entity public identity
being associated during registration with a network
address of the gateway, in such a way that a message
according to the call control protocol and addressed to
said public identity is transmitted to the gateway.
In the event of reception by the gateway of a
message according to the call control protocol, a step
of transferring said message from the gateway to all
the connected entities, and after receipt of the
message by a connected entity, a step of filtering of
the message by said entity, in the course of which the
entity determines whether the message is addressed to
the public identity allocated to it.
The method which is the subject of the invention
is furthermore noteworthy in that, in the case of a
message according to the SIP protocol, the step of
filtering the message is carried out on the basis of
the content of one at least of the fields of the group
comprising the field identifying the recipient of the
message and the field defining the unit handling the
processing of the message.
The residential gateway for linking to an IP
network a plurality of IP communication entities that
are able to implement a call control protocol, this
residential gateway connected to the IP network having
available an IP network address, which is the subject
of the invention, is noteworthy in that it comprises at
least one module for transferring to all the IP
communication entities connected to it messages

according to the call control protocol, that are
received by said gateway and addressed to a public
identity associated with one at least of the IP
communication entities connected to the gateway.
The IP communication entity to which a public
identity, which is the subject of the invention, is
allocated, is noteworthy in that it includes at least
one message filtering module designed to determine
whether a message received is addressed to the public
identity allocated thereto.
The IP communication entity, is furthermore
noteworthy in that it is able to be integrated into a
residential gateway and that it comprises means for
communicating with a non-IP external communication
terminal.
The IP communication entity, which is the subject
of the invention is finally noteworthy in that the
message filtering module is designed, on receipt of a
message, to analyze at least one of the fields of the
group comprising a field identifying the recipient of
the message and a field defining the entity handling
the processing of the message, said fields being
contained in the message received.
The method, the residential gateway and the
communication entity IP, which are the subjects of the
present invention, find application to the management
of the linking up of IP terminals and non-IP terminals
having a public identity and triggering a call control
protocol, such as domestic terminals or of a mono or
multimedia local network for analog telephones,
visiophones, PC personal computers, digital televisions
or others that can have one and the same public
identity.
They will be better understood on reading the
description and observing the drawings hereinafter in
which, in addition to Figures la with lc relating to
the prior art:

- Figure 2a represents, by way of illustration, a
flowchart of the essential steps for implementing the
method which is the subject of the present invention;
- Figure 2b represents by way of illustration a
flowchart according to a nonlimiting preferential mode
for implementing the step of transferring the
residential gateway to all the IP communication
entities on the basis of the residential gateway;
- Figure 2c represents, by way of illustration, an
exemplary implementation of the method for linking IP
communication entities to an IP network for an
installation comprising a residential gateway connected
to an SIP proxy and to two IP communication entities as
well as to a non-IP terminal, such as a fixed telephone
handset connected to an internal IP communication
entity integrated into the residential gateway, in
accordance with the subject of the present invention.
The method for linking to an IP network IP
communication entities that are able to implement a
call control protocol, by way of a local gateway, which
is the subject of the invention, will now be described
in a detailed manner. The IP communication entities are
internal or external to the local gateway. In the
particular, nonlimiting, example of the description,
the call control protocol is the SIP protocol and the
local gateway is a residential gateway, situated in a
user's residence.
In the particular example described for the
implementation of the method which is the subject of
the invention, we consider:
- the residential gateway, denoted Pz, z denoting
the IP address of the residential gateway,
- two IP communication entities consisting of IP
terminals, external to the gateway Pz and connected to
the latter, and denoted Ex,pu where x denotes the IP
address of the IP entity considered and pu the public
identity associated with the IP entity considered,

- an IP communication entity consisting of a VEG
(for VoIP Embedded Gateway) module, internal to the
gateway Pz and connected to the latter, and denoted Ey,pu
where y denotes the IP address of the entity considered
and pu the public identity associated with the IP
entity considered.
Of course, the invention can be applied to any
other system of this type comprising at least one
residential gateway and a plurality of IP communication
entities, internal or external to the gateway and
connected to the latter.
As will be observed in Figure 2a, the linkup
method which is the subject of the invention consists,
in a step A, in registering the public identity of each
connected communication entity, this public identity
being associated with the network address z of the
gateway Pz during registration.
In Figure 2a, this operation is denoted:
registration {{pu}tpu, z}
The aforesaid registration is performed in such a
way that any message according to the call control
protocol designated hereinafter, message denoted M(pu),
be it a call setup request or any other message
transmitted according to the call control protocol, to
this public identity pu is addressed to the residential
gateway Pz.
Step A, following the reception of this message
M(pu) by the residential gateway, is followed by a step
B of transferring the message M(pu) to all the IP
communication entities, internal Ex,pu or external Ey,pu
to the gateway Pz and connected to the latter, from the
residential gateway Pz.
In step B of Figure 2a, the transfer operation is
denoted:
Transfer M(pu) - Ex,pu; Ey,pu.
The aforesaid transfer operation B allows each of
the IP communication entities internal EPx,pu or external
EPy,Pu to the gateway Pz to thereafter filter the message

M(pu), so as to determine whether or not this message
is addressed to a public identity allocated to it.
In a general way, it is considered that the linkup
process;, in accordance with the linkup method which is
the subject of the invention, consists at least of
steps A, B, described with Figure 2a.
However, this linkup process for executing the
linkup method which is the subject of the invention is
then followed at the level of each IP communication
entity EX/PU, Ey,pu by a filtering process in step C
represented in the aforesaid Figure 2a.
As will be observed in Figure 2a, for a message
M(pu) each internal or external IP communication entity
can undertake, in a step Co, a verification by comparing
the public identity called in the message M(pu) with
its own public identity allocated to it.
This step is represented in step Co of Figure 2a by
the test relation:
pu = pu,x; pu,y ?
Through the aforesaid test, it is understood that
each internal or external IP communication entity that
is a recipient of the message M(pu) undertakes an
identification in the aforesaid step C0.
On a negative response to the test of the
aforesaid step Co, the internal or external IP
communication entity considered in step C2 ignores the
message.
Conversely on a positive response to the test of
step C0, that is to say in the event of identity between
the public identity called in the message received and
the public identity allocated to the internal or
external IP communication entity considered, step C0 is
followed by a step C1 of processing the aforesaid
message M(pu). In a specific manner, it is indicated
that the process for filtering the messages received,
these messages having been transmitted according to the
SIP protocol, consists in determining, for each message
received by an IP communication entity, whether the

message: is addressed to the public identity allocated
to this IP communication entity either on the basis of
the field identifying the recipient of the message,
that is to say the field denoted by field "To"
according to the SIP protocol, or on the basis of the
field defining the unit handling the processing of the
message, that is to say on the basis of the field
denoted "REQUEST URI" according to the SIP protocol.
When the internal or external IP communication
entity EX/PU Ey,pu is recognized to be a recipient for
example of a request, the latter performs the
processing associated with the reception of the
aforesaid request, this processing being able to
consist for example in the fact of ringing on receipt
of a call setup request, the ring occurring either at
the level of the IP communication entity, or conversely
at the level of the non-IP terminal when the latter is
linked to an internal IP communication entity
associated with it.
Otherwise, as is represented in Figure 2a, the
call setup request M(pu) is then ignored.
More specifically, the transfer step B of Figure
2a, is executed by transferring the message M(pu) over
the IP network to each of the external IP communication
entities connected on the basis of the residential
gateway Pz.
Conversely, in the case where the gateway
comprises and integrates internal IP communication
entities to which non-IP terminals are linked, the
residential gateway Pz forwards the aforesaid messages
M(pu) to each of the corresponding internal modules
VEG, as if it were in fact an IP terminal. The IP
communication entity invoked then processes the message
M(pu) in the same way as would an IP terminal.
A more detailed description of the transmission
operation B of Figure 2a will be now given in
conjunction with Figure 2b, this transmission operation

being performed at the level of the residential gateway
Pz.
In a general manner, it is indicated, by way of
nonlimiting example, that the registration operation A
can be performed by the network, this operation being
described subsequently in the description.
Under these conditions, the registration proper of
the whole set of public identities denoted {{pu}tPu, z}
associated with the network address z of the
residential gateway Pz is available at the level of the
aforesaid performed registration.
More specifically, during the transmission of a
call setup request M(pu), this request is transmitted
by way of an item of network equipment ER formed by an
SIP proxy when the SIP protocol is implemented, this
item of network equipment ER being associated, inter
alia with the gateway Pz and making it possible to
manage this gateway Pz.
With reference to Figure 2b, the item of network
equipment ER proceeds on receipt of the message M(pu)
to the recovery of the network address z of the
residential gateway Pz by identifying the public
identity called pu, on the basis of the registration
previously mentioned, in sub-step B0 of Figure 2b.
The item of network equipment ER then proceeds in
sub-step B1 to the transmission to the residential
gateway Pz of the message M(pu) at the address z which
was recovered in the previous step B0.
On receipt of the message M(pu) by the residential
gateway Pz, the latter, in sub-step B2/ undertakes the
transfer of the message M(pu) to the whole set of IP
communication entities internal or external to the
platform Pz and connected to the latter.
A more detailed description of the operative mode
of the linkup method, which is the subject of the
invention, will be now given in conjunction with Figure
2c in a nonlimiting specific domestic configuration
given solely by way of example.

The initial domestic configuration represented in
Figure 2c is considered in particular, in which the
gateway Pz whose IP network address is z = "1.1.1.4"
links two terminals associated with one and the same
public identity consisting of a telephone number + 33
14 52 94 814.
The first terminal, terminal of non-IP type, is
represented by an internal VEG module, constituting an
internal IP communication entity having an IP address y
= "10.1.1.1".
The second terminal of IP communication entity
type external to the gateway Pz and linked to the latter
has a network address x = "10.1.1.2".
As furthermore represented in Figure 2c, the
gateway Pz also links a third terminal, of external IP
communication entity type, whose public identity is
different + 33 14 52 96 496 and having a network
address x = "10.1.1.3".
In accordance with a noteworthy aspect of the
method which is the subject of the invention, step A
consisting in performing the registration can
advantageously include the creation of a location
database DB of the association between the set of first
and second aforesaid public identities and of the IP
address of the residential gateway Pz.
In Figure 2c it is understood that the aforesaid
registration comprises the public identities + 33 14 52
94 814 and + 33 14 52 96 496 referred to as numbers
associated with the target, that is to say with the IP
address of the residential gateway z = "1.1.1.4".
For the implementation of the aforesaid
registration several operative modes can be performed.
The aforesaid registration can, for example, be
configured by default in the location database DB upon
the user's subscription to the telephone service.
This registration can also be dynamic according to
the mechanism defined by the standard RFC32 61 of the
SIP protocol (for Session Initiation Protocol). Under

this assumption each terminal transmits a "REGISTER"
request to the network, the contact address contained
in these request messages corresponding to the contact
address of the residential gateway.
In the example given in conjunction with Figure
2c, during a call phase for example, the item of
network equipment ER responsible for the residential
gateway Pz receives a message constituting a request to
set up a call M(pu) destined for a public identity, the
number + 33 14 52 94 814 previously described. The item
of network equipment ER formed by the SIP proxy
recovers from the location database DB the network
address z associated with this public identity and
retransmits the call setup message to this address z.
The residential gateway Pz receiving this message
forwards it immediately to the internal or external IP
communication SIP entities that it links.
The IP terminals and the IP termination then
examine the SIP field "To" of this request, that is to
say the field containing the public identity of the
requested terminal, so as to determine whether this
request is or is not intended for them.
The two SIP external or internal IP communication
entities responding to the number + 33 14 52 94 814
then deduce from this analysis that the request is
intended for them and ring, while the IP communication
entity associated with the number + 33 14 52 96 496
ignores the aforesaid request message.
The rest of the call setup is performed as defined
in the standard RFC3261.
The chronology of the messages transmitted between
the network entity ER formed by the SIP proxy, the
residential gateway Pz and each of the IP communication
entities represented in Figure 2c is as follows:
1: INVITE; To + 33 14 52 94 814
2: DB Interrogation
3: INVITE; 1.1.1.4; To + 33 14 52 94 814
4a: Redirection; 1.1.1.4; + 33 14 52 94 814 to VEG

4b: INVITE; 1.1.1.4; To + 33 14 52 94 814 to
10.1.1.2
4c: INVITE; 1.1.1.4; To + 33 14 52 96 496 to
10.1.1.3
A more detailed description of a residential
gateway for linking to the IP network a plurality of
internal or external IP communication entities that are
able to implement a call control protocol, this
residential gateway connected to the IP network having
an IP address, in accordance with the subject of the
present invention, will be now given in conjunction
with Figure 2c.
As represented in Figure 2c, the residential
gateway Pz includes at least one transfer module denoted
TM with the function of forwarding to all the IP
communication entities, internal or external to the
gateway Pz and connected to the latter, the messages
received by the gateway Pz, and addressed to at least
one among the plurality of public identities
respectively associated with these connected IP
communication entities.
It is indicated that the aforesaid transfer module
TM can consist of a software module making it possible
to simply ensure the redirection of the message M(pu)
to any internal IP communication entity, such as a VEG
module associated with a non-IP terminal, as previously
described in conjunction with Figure 2c, or,
conversely, the transmission by network, that is to say
by transmission of an "INVITE" message within the
framework of the SIP protocol to any external IP
communication entity connected to the aforesaid
residential gateway Pz. These "INVITE" messages are
messages 4b and 4c of the figure previously mentioned
in the description.
The external respectively internal IP
communication entity having a public identity and an IP
address, in accordance with the subject of the present
invention, is noteworthy in that each of these latter

includes a module FM for filtering the messages M(pu)
received, whose function is to determine, for each
message received, whether this message is addressed to
the public identity allocated to the IP communication
entity considered.
This filtering module can consist of a software
module installed directly in the IP communication
entity considered and in particular in the VEG module
integrated into the residential gateway Pz.
When the filtering module FM is integrated into
the VEG module, that is to say into the IP
communication entity internal to the gateway Pz, this IP
communication entity advantageously comprises a module
for communicating with a non-IP terminal external to
the gateway Pz. The role of this communication module is
to ensure connection of the VEG module, internal to the
gateway Pz, to the non-IP terminal, external to the
gateway Pz, as well as communication between the VEG
module and the non-IP terminal.
As previously mentioned within the framework of
the description of the method which is the subject of
the invention, it is indicated that the filtering
module FM executes an evaluation either of the field
identifying the recipient of the message, or of the
field defining the unit handling the processing of this
message.
As mentioned previously in the description, it is
either the field "To" of the SIP messages or conversely
the field defining the unit handling the processing for
example the field comprising the network address
"10.1.1.1" of the internal IP communication entity
consisting of the VEG module integrated into the
gateway Pz represented in Figure 2c, for the non-IP
terminal associated with it.
The invention also covers a computer program for a
residential gateway comprising instructions able to
control the transferring, by the gateway, of a message
according to a call control protocol received by the

gateway, to all the IP communication entities connected
to it, when the program is executed by the gateway.
This program can be stored in or transmitted by a data
medium. The latter can be a hardware storage medium,
for example a CD-ROM, a magnetic diskette or a hard
disk, or else a transmissible medium such as an
electrical, optical or radio signal.
It is of course understood that the corresponding
program product is then stored either by downloading or
in any other way at the residential gateway Pz level and
in particular in the transfer module TM represented in
Figure 2c.
The invention also covers a computer program for
an IP communication entity, such as previously
described, to which a public identity is allocated,
comprising instructions for executing a filtering of
the messages according to a call control protocol
received by said entity so as to determine whether
these messages are addressed to the public identity of
said entity, when the program is executed by the IP
communication entity. This program can be stored in or
transmitted by a data medium. The latter can be a
hardware storage medium, for example a CD-ROM, a
magnetic diskette or a hard disk, or else a
transmissible medium such as an electrical, optical or
radio signal.
In the preceding description, the messages are
transmitted to the residential gateway according to the
SIP protocol. The invention also applies to the
transmission of messages according to the H323 protocol
or according to any other call control protocol
designed to be implemented by IP communication
entities, connected to the IP network but each
comprising a public identity which is allocated to
them, and distinguishing between the concept of public
identity and that of network address. To go back to the
particular example of the H323 protocol, this protocol
also envisages a registration phase making it possible

to register in the network the correspondence between a
user's public identity and the network address of his
location point in the network. It therefore suffices to
register, during this registration phase and via
messages defined by the H323 protocol, the
correspondence between the network address, in this
instance the IP address, of the residential gateway and
the respective public identities associated with the IP
communication entities that it links. The role of the
residential gateway is then to forward all the
messages, in particular the SETUP call setup requests
as defined by the H323 protocol, that it receives to
all the H323 entities that it links. In the same way as
in the case of the SIP protocol, each entity H323 is
left to handle the operation of filtering the messages
received so as to determine, for each message received,
whether or not it is intended for the entity
considered.

CLAIMS
1. A method for linking to an IP network, by way
of a residential gateway, a plurality of IP
communication entities to which are allocated
respective public identities and which are able to
implement a call control protocol, said IP
communication entities, internal or external to the
gateway, being connected to the latter, characterized
in that it comprises:
- a prior step of registering the respective public
identities of said IP communication entities, each
entity public identity being associated during
registration with a network address of the gateway, in
such a way that a message according to the call control
protocol and addressed to said public identity is
transmitted to the gateway;
- in the event of the receipt by the gateway of a
message according to the call control protocol, a step
of transferring said message from the gateway to all
the connected entities; and
- after receipt of the message by a connected entity, a
step of filtering of the message by said entity, in the
course of which the entity determines whether the
message is addressed to the public identity allocated
to it.
2. The method as claimed in claim 1, in which the
call control protocol is one of the protocols of the
group comprising the SIP protocol and the H323
protocol.
3. The method as claimed in claim 2, in which, in
the case of a message according to the SIP protocol,
the step of filtering the message is carried out on the
basis of the content of one at least of the fields of
the group comprising the field identifying the
recipient of the message and the field defining the
unit handling the processing of the message.

4. The method as claimed in one of claims 1 to 3,
in which, in the case where during the filtering step,
the IP communication entity determines that the message
received is addressed to the public identity allocated
to it, said entity executes a processing associated
with the message.
5. The method as claimed in one of claims 1 to 4,
in which, in the course of the prior registration step,
the respective public identities of the connected
entities and the network address of the associated
gateway are registered in a location database,
accessible to an item of routing network equipment
associated with the gateway.
6. The method as claimed in claim 5, in which, in
the event of reception by the item of routing network
equipment of a message to set up a call according to
the call control protocol, addressed to one of the
entities registered in association with the network
address of the gateway, the item of routing network
equipment recovers from said database the network
address of the gateway, on the basis of the public
identity to which the message is addressed, then
transmits the message to the gateway at said recovered
network address.

7. A residential gateway for linking to an IP
network a plurality of IP communication entities that
are able to implement a call control protocol, the
gateway connected to the IP network having available a
network address, characterized in that it comprises a
module for transferring to all the IP communication
entities connected to it messages according to the call
control protocol, that are received by said gateway and
addressed to a public identity associated with one at
least of the IP communication entities connected to the
gateway.
8. An IP communication entity, to which a public
identity is allocated, characterized in that it
comprises a message filtering module, designed to

determine whether a message received is addressed to
the public identity allocated thereto.
9. The IP communication entity, as claimed in
claim 8, characterized in that it is able to be
integrated into a residential gateway and that it
comprises means for communicating with a non-IP
external communication terminal.
10. The IP communication entity, as claimed in one
of claims 8 and 9, in which the message filtering
module is designed, on receipt of a message, to analyze
at least one of the fields of the group comprising a
field identifying the recipient of the message and a
field defining the entity handling the processing of
the message, said fields being contained in the message
received.
11. A computer program for a residential gateway,
characterized in that it comprises instructions
designed to control the transferring by the gateway of
a message according to a call control protocol,
received by said gateway, to all the IP communication
entities connected to the gateway, when it is executed
by the latter.
12. A computer program for an IP communication
entity, to which a public identity is allocated,
characterized in that it comprises instructions
designed to control the filtering of a message
according to a call control protocol, received by said
entity, so as to determine whether said message
receivec is addressed to the public identity which is
allocated to the entity, when said program is executed
by the latter.

The invention concerns a method for connection to IP
communication entities (Expu,EyPu) via a residential
gateway (Pz). It consists in registering (A) the public
identity (pu) of each connected terminal associated with the
network address (z) of the residential gateway, so that any message
should be addressed to said residential gateway (Pz)
and in transferring (B) said message to all the IP communication
entities connected to the residential gateway (Pz) thus
permitting each of the latter to filter (C) the message
and to determine whether the message is addressed to a
public identity which is assigned thereto. The invention is
applicable to IP terminals managed in accordance
with SIP or H323 protocol.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=Uy6O3MiERZGyqKVOza6j/Q==&loc=wDBSZCsAt7zoiVrqcFJsRw==

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Patent Number

272341

Indian Patent Application Number

2550/KOLNP/2008

PG Journal Number

14/2016

Publication Date

01-Apr-2016

Grant Date

30-Mar-2016

Date of Filing

23-Jun-2008

Name of Patentee

ORANGE

Applicant Address

78 RUE OLIVIER DE SERRES, F-75015 PARIS, FRANCE

Inventors:

#	Inventor's Name	Inventor's Address
1	PROUVOST, SEBASTIEN	11 BIS RUE ERNEST RENAN, F-92130 ISSY LES MOULINEAUX
2	CHATRAS, BRUNO	37 RUE CLAUDE DECAEN F-75012 PARIS
3	GARCIN, SEBASTIEN	20 RUE JEAN-BAPTISTE POTIN, F-92130 ISSY LES MOULINEAUX

PCT International Classification Number

H04L 29/06

PCT International Application Number

PCT/FR2006/002835

PCT International Filing date

2006-12-21

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	0513291	2005-12-23	France