FR3116975A1 - Method for notifying a change of an address of an access point - Google Patents

Abstract

The invention relates to a method for notifying at least one terminal of a change of at least one address of a network access point, said at least one terminal being connected to said access point, said method being implemented by a notification device and characterized in that it comprises: - a step of receiving a message comprising at least a first address of said access point; - a step of obtaining at least a second address; and when said at least one second address does not correspond to said at least one first address, - a step of notifying said at least one terminal of said change of at least one address of said access point. Figure for abstract: Figure 3

Description

Method for notifying a change of an address of an access point

1. Field of the invention

The invention relates to the field of telecommunications and more particularly to telecommunications using the IP (Internet Protocol) protocol.

2. Prior Art

The IP protocol is very widely used as a communication protocol by all types of computer applications such as Internet (Web) applications, telephony / video telephony, electronic messaging, TV services, banking applications, etc.

To use these applications/services, a user most often uses TCP/IP terminals connected to a network access point such as a home (fixed) or mobile gateway. In a known manner, the terminals/equipment connected to the local area network (LAN) of the fixed/mobile access point are assigned a private IPV4 or IPV6 IP address by a DHCP (Dynamic Host Configuration Protocol) server integrated into the access point. The access point obtains, from a network equipment of the telecommunications operator, thanks to an integrated DHCP or PPP (Point-to-Point Protocol) client, a public IP address. Note that the access point can also obtain a private IP address when a CGN (Carrier Grade NAT) function is used. When a LAN terminal wishes to communicate with equipment located outside the local network, for example with a service platform of the telecommunications operator, the fixed/mobile access point which uses the IPV4 protocol must implement an NAPT (Network Address Port Translation) function which makes it possible to replace the source IP address of the terminal with the public/WAN (Wide Area Network) IP address of the access point. The NAPT table also contains the destination IP address, destination port, transport protocol (User Datagram Protocol (UDP), Transmission Control Protocol (TCP), Stream Control Transport Protocol (SCTP), etc.). Thus, the service platform only directly interacts with the access point via its WAN interface. Responses to requests from terminals located in the local network of the access point are intercepted and routed by the latter to the destination terminal according to the data present in the NAPT table.

Some terminals that run applications such as VoIP applications (telephony, videotelephony), SMSoIP (Short Message Service over Internet Protocol), RCS (Rich Communication Services), messaging, mobile notification (Apple Push Notification System (APNS) / Firebase Google ) must be able to receive incoming messages (calls, messages, etc.) from service platforms. However, telecommunications operators generally allocate dynamic IP addresses to the WAN interfaces of access points with predetermined lifetimes. This improves the security aspects but also optimizes the number of public IP addresses used at a given time by customers. When the public IP address of the access point changes, it is possible that the terminals connected to the local network no longer receive incoming messages if the service platforms have not been aware of this change. For the service to be effective/available again, it is necessary either to wait for the periodic and predetermined renewal of the sending of a message by the LAN terminal to the service platform (for example, services using the SIP protocol rely on SIP REGISTER messages), or the detection by the terminal of a TCP session break which will trigger the sending of a registration message by the terminal to the service platform. Once the message has been received by the service platform, it will then know the new public IP address of the access point thanks to the information contained in the message.

In addition to this temporary unavailability involving a partial or total degradation of the service(s), this breach may also result in potential retransmissions of messages involving an increase in network traffic and the generation of error messages which may trigger alarms at network monitoring.

3. Disclosure of Invention

The invention improves the state of the art and proposes for this purpose a method for notifying at least one terminal of a change of at least one address of a network access point, said at least a terminal being connected to said access point, said method being implemented by a notification device and characterized in that it comprises:

- a step of receiving a message comprising at least a first address of said access point;

- a step of obtaining at least a second address;

and when said at least one second address does not correspond to said at least one first address,

- a step of sending at least one notification to said at least one terminal of said change of at least one address of said access point.

This mode of implementation makes it possible to notify a terminal connected to the access point of a change of address of the access point. Concretely, the method receives a message comprising an address of the access point, such as for example an IP address, and compares it with a second address obtained. The second address is for example obtained from a memory space of the device executing the method and may correspond to an address of the access point received previously (before the reception step). When the address received and the address obtained are not identical then a notification is sent to one or more terminals connected to the access point. Advantageously, the terminal(s) and more specifically the applications they run will then be able to notify the service platform(s) very quickly that their address, that is to say the address of the access point, has changed. and be reachable again.

By network access point, we mean equipment that allows a physical connection to a wired or radio network such as a home gateway, a router, a modem, a smartphone (connection sharing mode), etc.

Address means a sequence of characters and/or binary data used to identify a terminal or one of its electronic modules such as a server, a home gateway, a smartphone (in English “smart phone”), a computer , a connected object, a network card or interface or any other terminal connected to a network. An address is for example an IP V4 address, an IP V6 address, an IPV6 prefix, an FQDN (for Fully Qualified Domain Name in English) or a URI (for Uniform Resource Identifier in English).

According to a particular embodiment of the invention, a method as described above is characterized in that the transmission step is preceded by a step of obtaining at least one address of said at least a terminal.

This embodiment makes it possible, for example, to notify all or part of the terminals connected to the local network of the access point of the change of address of the access point. Obtaining the address or addresses of the terminals to be notified can for example be done according to the data present in an ARP table (for Address Resolution Protocol in English) of the access point, data present in an NAPT table (for Network Address and Port Translation in English) of the access point, of the data present in an IP routing table, of the terminals having a DHCP lease still active at the level of the DHCP server of the access point or even according to the service or services required by the terminals. The services are for example determined thanks to the destination and/or source port numbers (for example 5060 for the SIP protocol) used by the terminals/applications at the access point.

According to a particular embodiment of the invention, a method as described above is characterized in that the sending step is preceded by a step of registering said at least one terminal.

This embodiment makes it possible to notify one or more terminals, for example, according to a list listing the terminals which have previously registered/subscribed to the method in order to be notified of a change of address of the access point.

According to a particular embodiment of the invention, a method as described above is characterized in that said message is received from a DHCP or PPP or PCO (for Protocol Configuration Options) or DNS (for Domain Name Service in English) of said access point.

This mode of implementation makes it possible to obtain the new address of the access point as soon as it has been allocated and transmitted by the telecommunications operator to the DHCP or PPP or PCO or DNS client of the access point.

According to a particular embodiment of the invention, a method as described above is characterized in that the notification corresponds to an application IP packet.

This mode of implementation makes it possible to notify the terminal or terminals via an existing communication protocol of the IP type. The application IP packet is for example a message of the SIP NOTIFY type in “unsolicited” mode. Thus, the use of such a protocol does not involve any software and/or hardware modification of terminals or access points. Note that the mode can also be a "solicited" mode after the terminal(s) have sent a subscription message of the SIP SUBSCRIBE type to the access point's IP address change notification service.

According to a particular embodiment of the invention, a method as described above is characterized in that the notification corresponds to an ICMP request (for Internet Control Message Protocol in English).

This mode of implementation makes it possible to notify the terminal(s) via the native ICMP communication protocol, a protocol systematically present in all TCP/IP stacks, which allows access points to send error or supervision messages . The access point address change information can, for example, be contained in the data (optional and of variable length) of the ICMP payload. Thus, the use of such a protocol does not involve any software and/or hardware modification of terminals or access points.

According to a particular embodiment of the invention, a method as described above is characterized in that the notification corresponds to a DHCP request.

This mode of implementation makes it possible to notify the terminal(s) connected to the local network of the access point via the DHCP communication protocol. The notification can for example be a DHCP Release request which will involve restarting the DHCP attachment process of the terminals with the access point's DHCP server. Once the DHCP attach process is complete, endpoints notify the applications they are running. The applications then perform the same processing that they usually apply when they are started. In particular, they re-register at the service platforms and inform them of the new address assigned to the access point.

According to a particular embodiment of the invention, a method as described above is characterized in that the notification corresponds to a broadcast type request.

This mode of implementation makes it possible to notify all the terminals present in the local network of the access point. The data is broadcast via a broadcast address (broadcast) for example predetermined or previously obtained by the method.

According to a particular embodiment of the invention, a method as described above is characterized in that the notification corresponds to a unicast type request.

This mode of implementation makes it possible to individually notify terminals present in the local network of the access point.

According to a particular embodiment of the invention, a method as described above is characterized in that the notification corresponds to a request of the multicast type.

This mode of implementation makes it possible to notify a subset of the terminals present in the local network of the access point.

The invention also relates to a device for notifying at least one terminal of a change of at least one address of a network access point, said at least one terminal being connected to said access point, said device being characterized in that it comprises:

- a module for receiving a message comprising at least a first address of said access point;

- a module for obtaining at least a second address;

- a module for transmitting at least one notification, intended for said at least one terminal, of said change of at least one address of said access point.

The term module can correspond to a software component as well as to a hardware component or a set of hardware and software components, a software component itself corresponding to one or more computer programs or subroutines or more generally to any element of a program able to implement a function or a set of functions as described for the modules concerned. In the same way, a hardware component corresponds to any element of a hardware (or hardware) assembly capable of implementing a function or a set of functions for the module concerned (integrated circuit, smart card, memory card, etc. .).

The invention also relates to a computer program comprising instructions for implementing the above method according to any one of the particular embodiments described above, when said program is executed by a processor. The method can be implemented in various ways, in particular in wired form or in software form. This program may use any programming language, and be in the form of source code, object code, or intermediate code between source code and object code, such as in partially compiled form, or in any other desirable form.

The invention also relates to a recording medium or information medium readable by a computer, and comprising instructions of a computer program as mentioned above. The recording media mentioned above can be any entity or device capable of storing the program. For example, the medium may comprise a storage means, such as a ROM, for example a CD ROM or a microelectronic circuit ROM, or even a magnetic recording means, for example a hard disk. On the other hand, the recording media may correspond to a transmissible medium such as an electrical or optical signal, which may be conveyed via an electrical or optical cable, by radio or by other means. The programs according to the invention can in particular be downloaded from an Internet-type network.

Alternatively, the recording media may correspond to an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in the execution of the method in question.

This notification device and this computer program have characteristics and advantages similar to those previously described in relation to the notification method.

4. List of Figures

Other characteristics and advantages of the invention will appear more clearly on reading the following description of particular embodiments, given by way of simple illustrative and non-limiting examples, and the appended drawings, among which:

There presents an example of an implementation environment according to a particular embodiment of the invention,

There represents the hardware architecture of a notification device implementing the invention according to a particular embodiment,

There presents in the form of a flowchart the main steps of a notification method according to a particular embodiment.

5. Description of an embodiment of the invention

There illustrates an example of an environment for implementing the invention according to a particular embodiment of the invention. The environment represented in comprises terminals 100a, 100b, 100c connected to a network access point 101 via for example a wired and/or wireless connection. The terminals 100a, 100b, 100c can be any type of terminal making it possible to establish communication sessions such as telephone, videophone, instant messaging, SMSoIP sessions, data sessions, etc. These terminals can for example correspond to a mobile telephone, a fixed telephone, a smartphone (smart telephone in English), a tablet, a connected television, a connected object or a personal computer.

In the example described in support of the , the access point 101 is a home gateway connected to an access network 100 which can be a mobile access network of the GSM, EDGE, 3G, 3G+, 4G, 5G, WiFi type… or an access network landline type ADSL, Fiber, VDSL, Cable, WiMax, WiFi, etc. This environment also comprises a network equipment 102 of the telecommunications operator capable of allocating an IP address to the network access point 101. This network equipment 102 is for example for a fixed access network, a BAS server (Broadband Access Server ) / BRAS (Broadband Remote Access Server) / MSAN (Multi Services Access Network) implementing a PPPoE (point-to-point protocol over Ethernet) / PPPoA (point-to-point protocol over ATM) function or a router such as a BNG (Broadband Network Gateway) device implementing a DHCP function. In the case of a mobile access network, the equipment 102 can correspond to a GGSN (Gateway GPRS Support Node), PGW (Packet GateWay) or SMF (Session Management Function)/UPF (User Plane Function) equipment implementing a DHCP server function. The access network 100 is interconnected directly or indirectly via a collection network to the IP core network of the telecommunications operator (not shown). This IP core network is then interconnected to other IP networks such as the public Internet IP network, corporate extranet IP networks, or to service platforms made available by the telecommunications operator itself. same (VoIP telephone service platform, TV/VOD connected on their own IP network) or made available by third parties.

There represents the hardware architecture of a notification device D in accordance with the invention. In the embodiment described here, this device has the hardware architecture of a computer. It notably comprises a processor PROC, a random access memory MV, a read only memory MEM and a non-volatile flash memory MF. Such means are known per se and are not described in more detail here. The read only memory constitutes a recording medium in accordance with the invention, readable by the processor PROC and on which is recorded here a computer program PG in accordance with the invention, this program comprising instructions for implementing the steps of the notification method as described previously, when the program is executed by the processor PROC.

On initialization, the code instructions of the computer program PG are for example loaded into a memory before being executed by the processor PROC. The processor PROC of the processing unit UT notably implements the steps of the notification method according to any one of the particular embodiments described in relation to the , according to the instructions of the computer program PG.

The device D also comprises a module RECV able to receive a message comprising an address such as an IP address of the access point 101.

According to a particular embodiment of the invention, the message received by the RECV module comes from a DHCP server of the network equipment 102.

According to a particular embodiment of the invention, the message received by the RECV module comes from a DHCP client of the access point.

The device D can further comprise a comparison module COMP capable of comparing the IP address received by the module RECV with another IP address obtained by the module OBT. Obtaining the IP address is for example carried out from a digital storage space such as a database, a file or a memory.

According to a particular embodiment of the invention, the device comprises a database configured to store data such as the history of the IP addresses received by the RECV module.

Moreover, in the case where the comparison is negative, the device D comprises an SND module able to send a notification indicating that the access point has changed its IP address to one or more terminals connected to the point of access via its local network.

According to a particular embodiment of the invention, the RECV and SND modules are one and the same communication module.

There illustrates in the form of a flowchart the main steps of a notification method according to a particular embodiment. There consists of a terminal T capable of transmitting and receiving requests to and from the device D which executes the notification method. The device D is a module of the access point PA. The access point PA also comprises a DHCP client (DHCP-C) capable of receiving, from network equipment operated by the telecommunications operator (102), the public IP address(es) assigned to the access point. The access point further comprises a BDD module capable of storing the IP addresses of the terminals connected to the local area network of the access point. This BDD module is for example a memory space, a database, an ARP table, an NAPT table or a DCHP lease table.

There also consists of an application server/service platform SA capable of providing a service to the terminal T such as a telephony/videophone/messaging/etc. service. In this example the access point PA is a home gateway configured to use a dynamic public IP address.

During a step E10, the DHCP-C module will obtain a public IP address from the access point. This obtaining can be done when a reconnection of the access point to the network of the telecommunications operator is necessary. The reconnection is for example linked to a loss of connection of the access point following a degradation of the signal leading to transmission errors, to a desynchronization of the signal or even when the telecommunications operator voluntarily interrupts the PPP/DHCP sessions, by example, for reasons of maintenance, security, optimization of the number of IP addresses used at a given time by its customers, etc. When reconnecting, a public IP address is assigned by the operator to the PA access point. The assigned public IP address may be different from the previous one. In such a case, this poses a problem of continuity of service for all the services executed at the level of the terminal T which operate with messages in "push" mode (or incoming), that is to say at the initiative of the SA application server. Indeed, when using the IPV4 protocol, the only known IP address of the application server SA to reach the terminal T is that of the access point PA. When a message is transmitted by the service platform SA to the terminal T, the access point PA which is cut off from the messages exchanged, transmits the message to the correct terminal T thanks to the data stored in the NAPT table of the point PA access. If the public IP address of the access point PA changes, then the terminal T can no longer be reached by the service platform SA until the terminal T itself sends a request to the platform. form of SA services. When this request is received by the service platform SA, the latter obtains in the request the new public IP address of the access point, thus making it possible to rejoin the terminal T. The new public IP address of the access point access is for example obtained via the source IP address of the IP packet transporting the request or else via a field of the application protocol of the request such as for example the “Received” parameter of the SIP Via header for the SIP protocol.

During step E10, a message comprising the public IP address obtained from the access point is sent by the DHCP-C module to the device D.

According to a particular embodiment of the invention, the message can also include additional data, such as for example the cause of the reconnection, the date and/or the time, an identifier of the network interface of the access point , etc.

At step E20 the device D receives the message and retrieves the public IP address of the access point. The device D then compares the IP address received with an IP address obtained from, for example, a digital storage space (not shown) such as a database, a file or a memory. The IP address obtained is for example the last IP address received following the previous disconnection (before step E20) stored, for example, by the device D in the digital storage space. The comparison allows the device to ensure that there has been a change of public IP address at the access point.

According to a particular embodiment of the invention, during step E20 the device will also receive additional data from the DHCP-C module such as, for example, the cause of the reconnection, the date and/or time, an identifier the network interface of the access point that obtained the public IP address, etc. The device D can then store this data in the storage space for statistical purposes.

According to a particular embodiment of the invention, the digital storage space is included in the device D.

If the result of the comparison determines that there has indeed been a change of public IP address at the access point, then the device sends a notification to the terminal T (E23). The notification is then received by the terminal T during step E40.

According to a particular embodiment of the invention, the notification corresponds to an ICMP request which includes, in its payload data, information concerning the change of public IP address of the access point PA. When the terminal receives the notification, the TCP/IP stack sends this information back to one or more service applications running on the terminal. The information is then interpreted by the service application(s) in order to immediately restart a registration procedure at the level of the service platform(s).

According to a particular embodiment of the invention, the notification corresponds to an IP request comprising an application packet making it possible to inform the terminal T of the change of public IP address of the access point PA. The request is for example a message of the SIP NOTIFY type in “unsolicited” mode, that is to say having an implicit subscription to the notification service. The request can also be a SIP NOTIFY type message in “solicited” mode when the terminal T explicitly subscribes to the notification service by sending SIP SUBSCRIBE subscription messages beforehand and on a regular basis to the device D.

According to a particular embodiment of the invention, the notification corresponds to a DHCP request. The notification can for example be a DHCP Release request which will involve restarting the DHCP attachment process of the terminals with the access point's DHCP server. Once the DHCP attachment process is complete, the terminals inform the applications they are running of the access point's IP address change.

After receipt of the notification by the terminal T (E40), the latter sends a request (E41) to the service platform SA, which will allow the terminal T to be reachable again by the platform. form of SA services. Indeed, the latter will obtain the new public IP address of the access point from the request.

According to a particular embodiment of the invention, the notification sent by the device D in step E23 is a notification broadcast to all the terminals connected to the local network via a so-called broadcast request. This embodiment makes it possible to widely disseminate the information and to be sure that all the terminals obtain the information of the change of public IP address of the access point PA.

According to a particular embodiment of the invention, the notification sent by the device D in step E23 is a notification broadcast to a single terminal connected to the local network via a so-called unicast request. This mode of implementation makes it possible to target the terminal(s) to be notified of the change of public IP address of the access point PA.

According to a particular embodiment of the invention, the notification sent by the device D in step E23 is a notification broadcast to a subset of the terminals connected to the local network via a so-called multicast request. This mode of implementation makes it possible to notify certain terminals of the change of public IP address of the access point PA according, for example, to broadcasting rules interpreted by the device D.

According to a particular embodiment of the invention, the device D can obtain from a digital storage space (BDD) the addresses (IP and/or Mac) of the terminals to be notified via a request sent at E21 and a response received at E22 . The digital storage space (BDD) receives the request at E30 then sends a response to the device D at E31. The digital storage space (BDD) is for example a database, a file, a memory location or more precisely an NAPT table, an ARP table, an IP routing table or a DCHP lease table or a DNS table or DNS-cache.

According to a particular embodiment of the invention, the addresses of the terminals to be notified received in E22 can comprise one or more terminal addresses entered beforehand by the device D in the digital storage space BDD, following requests received in coming from one or more terminals present in the local area network of the access point and explicitly asking to be notified of the change of public IP address of the access point PA. The request can, for example, be made via the sending by the terminal of an ICMP packet including a dedicated “payload” of subscription to the notification of change of address of the access point intended for the device D and/or a dedicated address of the access point at the LAN level. Alternatively, the subscription to the notification of change of address of the access point by the terminal can be done via a SIP SUBSCRIBE message using a new "Event Package" dedicated to the notification service.

According to a particular embodiment of the invention, the device D can comprise the digital storage space BDD.

According to a particular embodiment of the invention, if the access point is assigned a private IP address by the network equipment and if the application server SA is accessible from another network (Internet, etc.), a CGN (Carrier Grade NAT) function is implemented in the network. This CGN feature provides a large-scale NAT feature whose purpose is to limit the number of public V4 IP addresses used by a telecommunications operator. In addition, this function also allows to manage tunneling mechanisms, for example, when an IPV4 packet is encapsulated in an IPV6 packet or is aimed and versa.

According to a particular embodiment of the invention, the protocol used by the terminals, the access point PA and the application server(s) is an IPV6 protocol. When the access point is assigned a new IPV6 address (that is to say a prefix) by a network equipment of the telecommunications operator (102), the terminals present in the local network of the access point are then notified by the device D, for example via ICMP packets, and take this new IPV6 prefix into account to auto-generate their own IP address (concatenation of their MAC address for example). Then, the terminals inform the service application(s) they are running so that they restart their registration cycle with the application server(s) SA. In this case, the application server SA only knows the address of the IPV6 terminal (address derived from the IPV6 prefix assigned to the access point) which is obtained via the message registering the terminal with the application server SA .

According to a particular embodiment of the invention, the device D is a terminal connected to the local network of the access point PA.

It goes without saying that the embodiment which has been described above has been given purely as an indication and in no way limiting, and that many modifications can be easily made by those skilled in the art without departing from the scope. of the invention.

Claims (12)

Method for notifying at least one terminal (T) of a change of at least one address of a network access point (PA), said at least one terminal being connected to said access point, said method being implemented by a notification device (D) and characterized in that it comprises:
- a step of receiving (E20) a message comprising at least a first address of said access point;
- a step of obtaining (E20) at least one second address;
and when said at least one second address does not correspond to said at least one first address,
- a step of sending (E23) at least one notification to said at least one terminal of said change of at least one address of said access point. Method according to claim 1, in which the transmission step is preceded by a step of obtaining (E22) at least one address of said at least one terminal. Method according to claim 1, in which the sending step is preceded by a step of registering said at least one terminal. A method according to claim 1 wherein said message is received from a DHCP or PPP or PCO or DNS client of said access point. Method according to Claim 1, in which the notification corresponds to an application IP packet. A method according to claim 1 wherein the notification corresponds to an ICMP request. A method according to claim 1 wherein the notification corresponds to a DHCP request. Method according to Claim 1, in which the notification corresponds to a request of the broadcast type. Method according to Claim 1, in which the notification corresponds to a request of the unicast type. Method according to Claim 1, in which the notification corresponds to a request of the multicast type. Device for notifying at least one terminal (T) of a change of at least one address of a network access point (PA), said at least one terminal being connected to said access point, said device being characterized in that it comprises:
- A reception module (RECV) of a message comprising at least a first address of said access point;
- a module for obtaining (OBT) at least a second address;
- a transmission module (SND) of at least one notification, intended for said at least one terminal, of said change of at least one address of said access point. Computer program comprising instructions for implementing the method according to any one of Claims 1 to 10, when the program is executed by a processor.