CN102792709A - Method and device for mobile multicast - Google Patents

Abstract

The invention provides a method and equipment for mobile multicast. The method includes receiving a request for reassociation from a mobile terminal; when the mobile terminal is using a multicast service, and the current access point providing services for the mobile terminal and the target access point to which the mobile terminal is to be reassociated are in the same robust When the security network is associated with the network, generate a multicast context information block as an information packet describing the multicast service of the mobile terminal; and send the multicast context information block to the target access point, so that the multicast service of the mobile terminal can Switch to the target access point. Through the technical solution proposed by the embodiment of the present invention, the mobile multicast service can be supported in the wireless local area network.

Description

Method and device for mobile multicasting Technical field

The present invention relates to the field of multicast, and in particular, to a method and equipment for mobile multicast. Background technique

With the rapid popularization of WiFi terminal devices, WiFi networks develop rapidly. Especially in China, for example, telecom operators are planning or have built numerous WiFi hotspots and hot spots in many cities to provide a certain degree of WiFi coverage and provide network access services to WiFi subscribers. For Chinese telecom operators, building a large-scale WiFi/WLAN network has become a basic strategy for them. After the network infrastructure is built, the most important and urgent next step is to provide users with rich and diverse value-added services on these large-scale WiFi/WLAN networks, so as to attract more WiFi users.

Telecom operators have good experience and foundation in transmitting IPTV services on traditional wired networks. Through WiFi networks, traditional IPTV services can be pushed to WiFi user equipment, so WiFi-based mobile IPTV has become the killer application of WiFi. However, when pushing the traditional IPTV service from the wired network to the wireless WiFi users, there are some technical problems. Multicast is the basic mechanism for implementing IPTV. However, from the beginning of design, multicast has not considered the support for user mobility. When the multicast-based IPTV service is projected to the WiFi device of the mobile user, a series of problems will be encountered.

Therefore, it is necessary to design a mobile multicast solution for the WiFi network, especially the operator's WiFi network, especially considering the combination of the existing IEEE 802.11 mobile support mechanism.

Considering the feasibility and practicability of the mobile multicast solution, there are various problems in the various mobile multicast solutions proposed so far for the actual network requirements of the large-scale WiFi/WLAN network.

1. There are many researches on mobile multicast and wireless multicast, however, there are many problems in the schemes of these researches. The main drawback is that these mobile multicast mechanisms are dependent on Mobile-IPv6 (ΜΙΡν6) and Mobile-IPv4 (MIPv4). Second, some other research focuses more on multicast routing. Among these schemes, Mobile Multicast and Mobile IP The tight coupling requirements of (MIP) and specific routing mechanisms greatly limit the application of mobile multicast in actual network environments. When actually deploying mobile IPTV, it is found that the current solution cannot meet the actual needs of WiFi networks. The simplest example Yes, MIP-based mobile multicast mechanisms usually do not work if mobile multicast does not involve layer 3 IP address changes. Therefore, for mobile multicast mechanisms, scalability and practical Actuality is a must.

2. Kai-Wen Cheng et al. (.Design and Analysis of Cooperative Mobile Multicast Protocol (CMMP) for Intermittent Network Connectivity, IEEE Transactions on Wireless Communications, Vol.8, No. 6, 2009. ) designed a mobile multicast protocol. However, this protocol requires a complex theory of cooperative communication between wireless channels and network elements, which is still in the theoretical research stage and lacks feasibility in actual network deployment.

3. In the IEEE 802.11 protocol suite, IEEE 802.1k and IEEE 802.11f are two mechanisms that support mobile terminals (MS) to switch between WiFi access points. However, IEEE 802.11r and IEEE 802.11f do not support mobile multicast, which hinders the practical deployment of these IEEE 802.11 protocols.

Therefore, there is a need for a method and equipment for mobile multicast, so that mobile multicast services can be supported in a wireless local area network. Contents of the invention

The embodiment of the present invention proposes a method and equipment for mobile multicast to support mobile multicast services in a wireless local area network.

According to one aspect of the present invention, a method for mobile multicast is proposed, including: receiving a request for reassociation from a mobile terminal; when the mobile terminal is using a multicast service and is providing services for the mobile terminal When the current access point of the mobile terminal and the target access point to which the mobile terminal will re-associate are in the same robust security network association network, generate a multicast as an information packet describing the multicast service of the mobile terminal a context information block; and sending the multicast context information block to the target access point, so that the multicast service of the mobile terminal can be switched to the target access point.

According to another aspect of the present invention, a mobile multicast method is proposed, including: receiving a multicast context information block from a current access point that is providing services for the mobile terminal, and the multicast context information block is for An information group describing the multicast service of the mobile terminal; judging whether there is a multicast group where the mobile terminal is located according to the extracted information, if not, sending an Internet Group Management Protocol (IGMP) join message to the multicast agent and performing a multicast operation according to the feedback result of the multicast agent, so as to switch the multicast service of the mobile terminal to the target access point.

According to yet another aspect of the present invention, a method for joining a multicast group is proposed, including: receiving an IGMP join message from a target access point to which the mobile terminal will re-associate; according to the IGMP join message, for the The target access point creates the multicast group where the mobile terminal is located, and feeds back the creation result to the target access point, so that the target access point can switch the multicast service of the mobile terminal to the target Access Point.

According to yet another aspect of the present invention, a multicast context transmission method is proposed, including: generating an information packet describing a multicast service being provided for a mobile terminal; sending the information packet to a other access points than the service access point, so that the multicast service can be seamlessly provided by the other access point.

According to yet another aspect of the present invention, an access point is proposed, including: an access point transceiver unit, configured to receive a mobile terminal's request for reassociation; an association determination unit: configured to determine whether the mobile terminal is using a group whether the current access point providing service for the mobile terminal and the target access point to which the mobile terminal will re-associate are in the same robust security network associated network; and a multicast context information block generation unit , used to generate a multicast context information block as an information packet describing the multicast service of the mobile terminal when the judgment results are all yes, and transmit the information to the target through the access point transceiver unit The access point sends the multicast context information block, so that the multicast service of the mobile terminal can be switched to the target access point.

According to another aspect of the present invention, an access point is proposed, including; an access point transceiver unit, configured to receive a multicast context information block from a current access point that is providing services for the mobile terminal, the The multicast context information block is an information packet describing the multicast service of the mobile terminal; the information extraction unit is configured to extract information related to the multicast service from the multicast context information block, and according to the extracted information Judging whether there is a multicast group where the mobile terminal is located, if not, sending an Internet Group Management Protocol (IGMP) join message to the multicast agent through the access point transceiver unit; and the multicast operation unit: used to: Based on the feedback result of the multicast agent, perform a multicast operation to switch the multicast service of the mobile terminal to the target access point.

According to another aspect of the present invention, a multicast proxy is proposed, including: a proxy transceiver unit, configured to receive an IGMP join message from a target access point to which the mobile terminal will re-associate; a multicast creation unit, configured to the IGMP join message, create the multicast group where the mobile terminal is located for the target access point, and feed back the creation result to the target access point, so that the target access point can send the mobile terminal's The multicast service is switched to the target access point.

According to yet another aspect of the present invention, a system for mobile multicast is proposed, including the above two access points, the above multicast proxy, and a mobile terminal. Through the technical solution proposed by the embodiments of the present invention, the mobile multicast service can be supported in the wireless local area network, especially, it is possible to switch the mobile multicast service through the IEEE 802.11r and IEEE 802.11f communication protocols. Description of drawings

According to the following description in conjunction with the accompanying drawings, the advantages of the present invention will become easy to understand, wherein - Fig. 1 shows a schematic diagram of a system for mobile multicast according to an embodiment of the present invention;

FIG. 2 shows a structural block diagram of an access point device according to an embodiment of the present invention;

Fig. 3 shows a flowchart of a mobile multicast method according to an embodiment of the present invention. specific embodiment

Preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings, and unnecessary details and functions for the present invention are omitted in the description process to prevent confusion to the understanding of the present invention.

Protocols in the IEEE 802.11 protocol suite IEEE 802.11r and 802.11f are two protocols that enable WiFi/WLAN users to move and switch quickly. However, the current IEEE 802.111 and 802.11f do not support mobile multicast, which hinders the actual deployment of the IEEE 802.11 protocol. An exemplary description will be given below for the IEEE 802.11 protocol. However, it should be realized that the following technical solutions can also be used for other protocols, such as the Control and Configuration of Wireless Access Points (CAPWAP) protocol.

In an embodiment of the present invention, a system for mobile multicast is proposed. As shown in FIG. 1, the system includes two access point devices (AP), a multicast proxy, and a mobile terminal (MS ). Persons skilled in the art should know that FIG. 1 is only a schematic system diagram illustrating an embodiment of the present invention. In an actual deployed system, there may be multiple APs, multiple multicast agents, and multiple MSs, and the structure of the system may also be Can be more complicated. In the following description, it is assumed that API is the current AP that is providing services for the MS, and AP2 is the target AP to which the MS will re-associate.

An access point device (AP) is also proposed. As shown in FIG. 2, the AP includes an AP transceiver unit 210, which is used to receive a request from the MS for re-association. The association judging unit 220 is configured to judge whether the MS requesting re-association is using the multicast service and whether the current AP and the target AP are in the same Robust Security Network Association (RSNA) network. The MCB generation unit 230 is configured to generate a multicast context information block (MCB, multicast context block) when the judgment results of the association judgment unit are all yes. The information grouping described by the multicast service.

The AP also includes an information extraction unit 240, configured to extract information related to the multicast service from the MCB (that is, IPTV/multicast information in the MCB) when the AP is the target AP to which the MS will re-associate. , and according to the information, detect whether the AP already has the multicast group where the MS is located, if not, send an IGMP join message to the multicast agent of the network through the AP transceiver unit 210 to join the MS contained in the MCB The multicast group to which it belongs.

The AP also includes a multicast operation unit 250, which is used to perform multicast operations, such as joining the multicast group where the MS belongs.

The AP also includes an association operation unit 260, configured to re-associate the MS with the AP under the condition that the AP is the target AP to which the MS will re-associate, so that the multicast service is provided to the MS through the AP.

A multicast proxy is also provided. As shown in FIG. 3, the multicast proxy includes a proxy transceiver unit 310 for receiving a message (for example, an IGMP multicast join message) sent by a target AP to which the MS will re-associate. The multicast creating unit 320 is configured to add the MS to the multicast group in advance according to the received message, that is, create the multicast group where the MS is located for the target AP.

Although the AP and the multicast agent in the embodiment of the present invention are described above in the form of separate functional modules, each component shown in FIG. 2 and FIG. 3 can be implemented by multiple devices in practical applications. Each component can also be integrated in a chip or a device in practical applications. The AP and multicast proxy may include any elements and devices used for other purposes. It is also possible to use different components in the above-described AP at different stages of the multicast service, or place different components in different devices. For example, if the AP is the current AP that is providing services for the MS, the used It is the association judgment unit 220 and the MCB generation unit 230, and if the AP is the target AP, the information extraction unit 240, the multicast operation unit 250 and the association operation unit 260 are used. Therefore, different devices may only include the required components.

Referring to the mobile multicast method shown in FIG. 4, the above-mentioned AP and multicast agent will be described in detail.

Fig. 4 is a flowchart of a mobile multicast method according to an embodiment of the present invention.

In step 410, the AP transceiving unit 210 of the API (gp, current serving AP of the MS) receives a request for re-association from the MS. In step 420, the API association judging unit 220 judges: ① whether the MS is currently using the multicast service and ② whether the API and the target AP2 (that is, the target AP to which the MS will re-associate) are in the same RSNA network.

Judgment ① in step 420 means that if a handover occurs in the future, for example, when the MS is handed over from API to AP2, the IPTV/multicast service of the MS will also be seamlessly handed over from API to AP2.

If one of the above two judgments is not established, the process proceeds to step 480, and the MS is directly re-associated with AP2.

If the above two judgments are all true, the process proceeds to step 430, and the MCB generation unit 230 in the API generates an MCB, and sends it to AP2 through the AP transceiver unit 210.

Taking the IEEE 802.11 r/f protocol as an example, the MCB can be defined to describe and include the multicast information of the MS. An example of defining an MCB is shown below:

MCB <

MS's MAC address

Join the IP address of the multicast group;,

QoS parameters of IPTV channel;

Security parameters, etc.;

>

In this example, the MCB includes the MAC address of the MS, the IP address to join the multicast group, and the QoS parameters of the IPTV channel. However, it should be emphasized that the size and content of the MCB are not fixed, and in other examples, the MCB can be dynamically expanded according to actual needs to include more multicast information and/or IPTV parameters.

However, if the content of the MCB only includes the MAC address of the MS, it means that the MS does not use any IPTV/multicast, so such an MCB is invalid.

Returning now to FIG. 4, in step 440, the AP transceiver unit 210 of AP2 receives the MCB sent by the API, and the information extraction unit 240 extracts information related to the multicast service contained in the MCB (SP, IPTV/multicast information) .

In step 450, the information extraction unit 240 of AP2 detects whether AP2 already has a multicast group where the MS is located according to the information. If not, then in step 400, the AP transceiver unit 210 sends a standard IGMP join message to the multicast proxy of the network, so as to join the multicast group where the MS contained in the MCB is located.

The multicast creation unit 320 in the multicast proxy creates a multicast group where the MS is located for the target AP (ie, AP2), and feeds back the result to AP2. The multicast group creation here can be performed according to the multicast group creation process in the specific protocol, and no further elaboration will be made here.

In step 470, the multicast operation unit 250 in AP2 performs multicast operations according to the feedback result from the multicast agent, where the multicast operations include conventional multicast operations such as joining a multicast group and registering. The feedback result here can be a standard message in the multicast business process.

In step 480, the association operation unit 260 in AP2 re-associates the MS from the API to AP2, so that the IPTV/multicast service can continue to be provided for the MS through AP2.

The mobile multicast method of the present invention is described below by taking IEEE 802.1 lr and IEEE 802.1 If as examples. example one

According to IEEE 802.1 lr, an MCB can be created in a Resource Information Memory (RIC) embedded in an IEEE 802.11 message. The specific method may be to extend the RIC to carry the MCB delivered by the resource request message. In the RSNA of IEEE 802.11, the resource request and the resource response are exchanged after the pairwise temporary key (PTK) is established, and the resource request and the resource response are protected by the integrity check of the message to ensure the security of the MCB. The IEEE 802.11r frame structure after MCB extension is as follows:

Table 1 Extended IEEE 802.1 lr frame structure

The structure of the IEEE802.Ur fast BSS transformation information element is shown in Table 2:

Table 2. Fast BSS transformation information elements

Meta ID Length MS MAC Service Multicast Group 1PTV Parameters Security Parameters

58 Addresses IP Milk Channel QoS Number It can be seen that in the embodiment of the present invention, the frame structure of IEEE 802.11 is extended, two information elements of "resource information memory-data" and "resource information memory-MCB" are added, and the "fast BSS conversion information element "has been modified so that the MCB is carried in the IEEE 802.11 message.

Example 2

A Multicast Context Block (MCB) can be created in the IAPP-MOVE message of IEEE 802.1 If. The Inter Access Point Protocol (IAPP) supports the transfer of MS content information between peer APs. The two IAPP messages (IAPP MOVE-notify and IAPP-MOVE.indicatkm) can carry content information, and can carry MCB in the extended content block of the MOVE-response packet. The MCB must be visible in the IAPP MOVE-response packet indicating the MS's current multicast service.

When receiving IAPP MOVE-notify and IAPP-MOVE.indication, the multicast operation unit of the API

250 will generate the IAPP MOVE-response including all the multicast content information created by the API:

IAPP-MOVE. response {

MAC address,

serial number,

AP address,

Multicast Context Information Block

state

}

After receiving the service primitive (primitive), the API will involve forwarding all relevant content of the re-associated MS to the peer IAPP entity of AP2 (after the handover is completed), wherein AP2 sends the IAPP MOVE The -response packet is associated with the MS, after which the API may discard any multicast content addressed to the MS identified by the MAC address parameter.

It should be appreciated that the technology provided by the embodiments of the present invention is not only applicable to IEEE 802.1 l r/f, but also applicable to other systems that can implement mobile multicast, for example, when using Control and Configuration of Wireless Access Points (CAPWAP) protocol, only need to provide the access controller (AC) with components with the same function as the components used by the AP in the above technical solution, and use messages similar to the messages used in the above technical solution, the implementation of the present invention can be realized The technical solution disclosed in the example.

Those skilled in the art should easily recognize that different steps of the above method can be implemented by programming a computer. Here, some embodiments also include machine-readable or computer-readable program storage devices (eg, digital word data storage medium) and encoded machine-executable or computer-executable program instructions, wherein the instructions execute some or all of the steps of the above method. For example, program storage devices may be digital memories, magnetic storage media (such as a magnetic disks and magnetic tapes), hardware, or optically readable digital data storage media. Embodiments also include programmed computers to perform said steps of the methods described above.

The description and drawings merely illustrate the principles of the invention. Therefore, it should be appreciated that those skilled in the art can suggest different structures. Although these different structures are not explicitly described or shown here, they embody the principle of the present invention and are included within its spirit and scope. Furthermore, all examples mentioned herein are expressly intended primarily for teaching purposes only to assist the reader in understanding the principles of the invention as well as the ideas contributed by the inventors to advance the art, and should be construed as non-references to these specifically mentioned examples. and conditional restrictions. In addition, all statements referring to the principles, aspects and embodiments of the present invention and their specific examples herein include their equivalents.

The above description is only used to implement the embodiments of the present invention, and those skilled in the art should understand that any modification or partial replacement without departing from the scope of the present invention should belong to the scope defined by the claims of the present invention. Therefore, The protection scope of the present invention should be based on the protection scope of the claims.

Claims (11)

Rights request 1. A method for mobile multicast, comprising: Receiving a request from the mobile terminal to re-associate; When the mobile terminal is using the multicast service, and the current access point providing services for the mobile terminal and the target access point to which the mobile terminal will re-associate are in the same robust security network association network , generating a multicast context information block as an information packet describing the multicast service of the mobile terminal; and sending the multicast context information block to the target access point, so that the multicast service of the mobile terminal can be switched to the target access point. 2. The method according to claim 1, further comprising: The content of the MCB is dynamically expanded according to the needs of the implementation. 3. The method according to claim 1 or 2, wherein sending the multicast context information block to the target access point comprises: Sending the multicast context information block to the target access point through an extension of the IEEE 802.11 frame structure; or sending the multicast context information block to the target access point in an access network interior protocol (IAPP) message. 4. A method for mobile multicast, comprising: Receive a multicast context information block from a current access point that is providing services for the mobile terminal, where the multicast context information block is an information packet describing the multicast service of the mobile terminal; judging whether there is a multicast group where the mobile terminal is located according to the extracted information, and if not, sending an Internet Group Management Protocol (IGMP) join message to the multicast agent; and Performing a multicast operation according to the feedback result of the multicast agent, so as to switch the multicast service of the mobile terminal to the target access point. 5. The method according to claim 4, further comprising: After the multicast service of the mobile terminal is switched to the target access point, the reassociation of the mobile terminal to the target access point is completed. 6. A method of joining a multicast group, comprising: receiving an IGMP join message from a target access point to which the mobile terminal is to re-associate; According to the IGMP join message, create the multicast group where the mobile terminal is located for the target access point, and feed back the creation result to the target access point, so that the target access point can add the mobile terminal The multicast service of the terminal is switched to the target access point. 7. A method for transmitting a multicast context, comprising: generating an information packet describing a multicast service being provided for a mobile terminal; sending the information packet to other access points except the access point providing the multicast service, so that the multicast service can be seamlessly handed over to be provided by the other access point. 8. An access point, comprising: An access point transceiver unit, configured to receive a request for reassociation from the mobile terminal; Association judging unit: used to judge whether the mobile terminal is using the multicast service and whether the current access point that is providing services for the mobile terminal and the target access point to which the mobile terminal will re-associate are in the same location In the associated network of the stick security network; and a multicast context information block generation unit, configured to generate a multicast context information block as an information packet describing the multicast service of the mobile terminal according to the positive judgment result of the association judgment unit, and sending the multicast context information block to the target access point through the access point transceiving unit, so that the multicast service of the mobile terminal can be switched to the target access point. 9. The access point according to claim 8, wherein, the current access point and the target access point are access points used in the IEEE 802.11 protocol suite or wireless access point control and configuration protocols access controller. 10. An access point, comprising: An access point transceiver unit, configured to receive a multicast context information block from the current access point that is providing services for the mobile terminal, the multicast context information block describes the multicast service of the mobile terminal information grouping; an information extraction unit, configured to extract information related to the multicast service from the multicast context information block, and judge whether there is a multicast group where the mobile terminal is located according to the extracted information, and if not, through the interface The entry point transceiver unit sends an Internet Group Management Protocol (IGMP) join message to the multicast agent; and the multicast operation unit: is used to perform a multicast operation according to the feedback result of the multicast agent so as to broadcast the multicast of the mobile terminal The service is switched to the target access point. 11. The access point according to claim 10, further comprising: a re-association unit, configured to re-associate the mobile terminal with the target access point after switching the multicast service of the mobile terminal to the target access point, so as to serve the The mobile terminal continues to provide multicast services. 12. The access point according to claim 10 or 11, wherein the current access point and the target access point are access points or wireless access point control and configuration used in the IEEE 802.11 protocol suite The access controller in the protocol. 13. A multicast agent, comprising: an agent transceiver unit, configured to receive an IGMP join message from a target access point to which the mobile terminal will re-associate; a multicast creation unit, configured to create, for the target access point, the multicast group in which the mobile terminal is located according to the IGMP join message, and feed back a creation result to the target access point, so that the target access point The access point can switch the multicast service of the mobile terminal to the target access point. 14. A system for mobile multicast, comprising the access point according to claim 8 or 9, the access point according to any one of claims 10 to 12, the access point according to claim 13 Multicast agent and mobile terminal