CN101369994A - A method, device and system for implementing multicast group membership management protocol proxy - Google Patents

Abstract

The invention discloses a method for realizing multicast group member management protocol agent. One upstream stream interface and at least one downstream stream interface are set on the media gateway (MG), and the media gateway controller (MGC) maintains and synthesizes each downstream stream interface. The multicast group member database of the subscription status of multicast group members. The MG receives the report message of joining the multicast group or the message of leaving the multicast group from the downstream network at the downstream flow interface, and reports it to the MGC; The message of the multicast group updates the content in the multicast group member database; the MGC judges whether the multicast group member database has changed, and if so, instructs the MG to send a report message to the upstream network on the upstream flow interface or leave the multicast group group message. The invention also discloses another method for realizing the proxy of the multicast group member management protocol, as well as a system and a device for realizing the proxy of the multicast group member management protocol. The solution of the invention can make the MG have the agent function of the multicast group member management protocol.

Description

A method, device and system for implementing multicast group membership management protocol proxy

technical field

The invention relates to the field of multicast technology, in particular to a method, device and system for realizing multicast group member management protocol proxy.

Background technique

IP multicast (multicast) or multicast refers to sending data packets to a certain subset of nodes in the network in the IP network. This subset is called a multicast group (multicast group). The basic idea of IP multicast is that the source host only sends one copy of data, and the destination address in this data is the address of the multicast group; all destination hosts in the multicast group can receive the same data copy, and the multicast group Other hosts cannot receive it. A multicast group is identified by a class D IP address (224.0.0.0 to 239.255.255.255).

According to the scope of the protocol, the multicast protocol is divided into the host-router protocol, that is, the multicast group member management protocol; and the router-router protocol, mainly various multicast routing protocols. Multicast group membership management protocols include Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (Multicast Listener Discovery, MLD), etc.; multicast routing protocols are divided into intra-domain multicast routing protocols and inter-domain multicast routing protocols. kind.

Through the multicast group member management protocol, the multicast group membership information in the IP subnet (subnet) where its interface is located is established in the router. Specifically, this information is each multicast group, or further subdivided To filter on the multicast source address, whether there are active members in this IP subnet. The intra-domain multicast routing protocol uses certain multicast routing algorithms to construct a multicast distribution tree based on these multicast group membership information, and establishes multicast routing states in routers, and routers forward multicast packets based on these states. According to the inter-domain multicast routing policy configured in the network, the inter-domain multicast routing protocol publishes multicast-capable routing information and multicast source information among autonomous systems (ASs), so that multicast data can be distributed in domains. transfer between. The IGMP protocol is used for group member management in the IPV4 network, and the protocol MLD, which is similar in function and content to IGMP, is used in the IPV6 network. The following takes IGMP as an example to further introduce the multicast group membership management protocol.

The IGMP protocol runs between the host and the multicast router directly connected to the host. The function of IGMP is bidirectional: on the one hand, through the IGMP protocol, the host informs the multicast router that it wants to join and receive information about a specific multicast group; On the other hand, the multicast router periodically inquires whether the members of a known multicast group in the LAN are active through the IGMP protocol, that is, whether the network segment still has members belonging to a certain multicast group, and realizes that the connected network Group membership collection and maintenance. Through IGMP, the information recorded in the router is whether a certain multicast group has local members, rather than the corresponding relationship between the multicast group and the host.

So far, there are three versions of IGMP. IGMPv1 (RFC1112) defines the basic group member query and reporting process; IGMPv2 is defined by RFC2236, which adds a mechanism for group members to leave quickly on the basis of IGMPv1; the main function added in IGMPv3 (RFC3376) is that members can specify to receive or Specify not to receive packets from certain multicast sources, that is, add the function of filtering multicast source addresses. The following focuses on the principles of the IGMPv2 protocol.

When there are multiple multicast routers in the same network segment, IGMPv2 elects a unique querier through the querier election mechanism. The querier periodically sends general group query messages to query membership; the host sends report messages to respond to queries. The time when the host sends the report message is random. When it detects that other members in the same network segment send the same message, it suppresses its own response message. If a new host wants to join the multicast group, it does not need to wait for the query message from the querier, but actively sends a report message. When leaving a multicast group, the host sends a leaving group message; after receiving the leaving group message, the querier sends a specific group query message to determine whether all group members have left. A router that is a member of a group behaves like a normal host, responding to queries from other routers. Through the above mechanism, a table is established in the multicast router, which records which groups are members on the subnet corresponding to each interface of the router. When a router receives a data packet of a certain multicast group, it only forwards the data packet to the interfaces of the members of the multicast group. A host has joined a multicast group and must periodically send report messages to maintain its status. The multicast router starts the group membership interval (GroupMembership Interval) timer, and does not receive the report message that the host maintains the state before the timer expires, then deletes the membership of the group of the subnet. There are other multicast timers, such as: Query Interval timer, when the timer expires, a general query message is sent. Last Member Query Interval (Last Member Query Interval) timer, after receiving the message of leaving the group sent by the host, the querier sends a specific group query message to determine whether all group members have left, and starts the timer, every time It will be resent when it times out, and the number of sendings is determined by the LastMember Query Count. If the timer of the last query expires and no report message has been received from the group members of the group that has been left, the group member of the subnet will be deleted. Group membership. In addition, as a host, the Unsolicited Report Interval timer is also needed to control the time for the host to repeatedly send unsolicited report messages, and the Query Response Interval timer is used to control the time for the host to respond to query messages.

Multicast routing can be divided into two categories: Source Tree and Shared Tree. The source tree refers to a forwarding tree that uses the multicast source as the tree root and combines the shortest paths from the multicast source to each receiver. Since the source tree uses the shortest path from the multicast source to the receiver, it is also called the shortest path tree (shortest path tree, SPT). For a certain multicast group, the network needs to build a tree for any multicast source that sends packets to the group. The shared tree uses a router as the root of the routing tree. This router is called a rendezvous point (Rendezvous Point, RP), and combines the shortest paths from the RP to all receivers to form a forwarding tree. When using a shared tree, there is only one tree in the network corresponding to a certain group. All multicast sources and receivers use this tree to send and receive packets. The multicast source first sends data packets to the root of the tree, and then forwards the packets downward to all receivers. In multicast, a message is sent to a group of receivers identified by a logical address. After receiving the message, the router must determine the upstream (pointing to the multicast source) and downstream directions according to the source and destination addresses, and forward the message along the direction away from the multicast source. This process is called Reverse Path Forwarding (RPF).

The multicast routing protocol is more complicated than the multicast group member management protocol, so the requirements for equipment are relatively high. RFC4605 introduced the multicast group member management protocol proxy technology, specifically the IGMP/MLD proxy (proxy) technology. When the network topology is relatively simple, it is not necessary to run the multicast routing protocol, but to introduce the multicast group-based The proxy device of the member management protocol, which replicates and forwards the multicast data stream. That is to say, the proxy device learns the multicast group member information through the proxy multicast group member management protocol message, and forwards the multicast data stream according to the multicast group member information. Using the multicast group member management protocol proxy technology can save the cost of equipment and speed up deployment, and when the proxy device is deployed between the core network and the access network, the proxy device does not need to support the multicast routing protocol of the core network , and only need to send the multicast group member management protocol message to it, which enhances the versatility of the proxy device.

The realization principle of the IGMP/MLD proxy is: the host interface of the proxy device, also known as the upstream stream interface (Upstream Interface), points to the direction of the root node of the shared tree or the source tree. On this interface, run the IGMP host function. The proxy device maintains a multicast group membership database (Membership Database), and the records in the database are the merging (merge, or summary) of the multicast group membership information (membership information) of each downstream flow interface, which can also be said to be each Merge of the subscription status (subscription) of the multicast group of the downstream flow interface. See RFC4605 for the merging rules, and the format of each record is (multicast group address, filter condition, multicast source address list). The member database is equivalent to the sum of records of the multicast group member states of the proxy device as a host on the IP subnet where the upstream flow interface is located. When an IGMP query packet is received on the upstream flow interface, the proxy device queries the member database and sends an IGMP membership report on the host port. When the member database changes, it actively sends a leave or join multicast packet to the connected router. The IGMP/MLD agent also records the multicast subscription status on each downstream flow interface. The host interface receives the multicast data flow that matches the membership database record, and then forwards the multicast packet according to the multicast group membership status on each downstream flow interface. . The router interface of the proxy device, also known as the downstream interface (Downstream Interface), deviates from the root node and connects to the host. The proxy device runs the IGMP router function on this port, and performs group member registration, inquiry and deletion of users in the connected IP subnet. Realize receiving member report message and leaving multicast group request; sending query packet; forwarding the received multicast data packet to the downstream flow interface of the multicast group member with multicast data flow. The IGMP/MLD proxy must also be able to become a querier through election in the subnet where the downstream flow interface is located, so that it can become the only device that forwards multicast data streams in the subnet.

Media Gateway Controller (MGC) and Media Gateway (MG) are two key components in a packet network. The network architecture composed of MGC and MG is shown in Figure 1. The MGC is responsible for the call control function, the MG is responsible for the service bearer function, and the MGs interact through the Real-time Transport Protocol (RTP). The gateway control protocol is the main protocol for communication between MG and MGC. At present, H.248/MeGaCo and Media Gateway Control Protocol (MGCP) are widely used.

Taking the H.248 protocol as an example, various resources on the MG are abstractly expressed as Termination. Terminals are divided into physical terminals and ephemeral terminals. The former represents some semi-permanent physical entities, such as TDM channels, etc., and the latter represents some public resources released after temporary application, such as RTP streams. In addition, the Root terminal represents the MG as a whole. The combination between terminals is abstractly represented as a context (Context). A context can contain multiple terminals, so topology (Topology) is used to describe the relationship between terminals. For terminals that have not yet been associated with other terminals, they are contained by a special context called a Null context. Based on this abstract model, the connection of a call is actually an operation on the terminal and the context.

Since the MG currently does not have the ability to process IGMP/MLD protocol messages and multicast routing protocol messages, if there is a media gateway on the bearer path, the IGMP/MLD protocol message will be blocked by the media gateway.

Contents of the invention

In view of this, the embodiment of the present invention proposes a method for realizing the proxy of the multicast group member management protocol, so that the MG can have the function of the proxy of the multicast group member management protocol. The method sets an upstream stream interface and at least one downstream stream interface on the MG, and the MG maintains a multicast group member database that summarizes the multicast group member information of all downstream stream interfaces of the MG, and includes the following steps:

The MG receives the multicast group membership management protocol message from the downstream network at the downstream flow interface, and updates the contents of the multicast group membership database according to the multicast group membership management protocol message, and the MG judges the multicast group membership database Whether there is a change, if so, send a multicast group membership management protocol message to the upstream network on the upstream flow interface;

or,

The MG receives the query message on the upstream flow interface, searches the contents of the multicast group membership database according to the query message, and sends a report message to the upstream network through the upstream flow interface if a matching content is found.

The embodiment of the present invention also discloses another method for realizing multicast group member management protocol proxy. One upstream flow interface and at least one downstream flow interface are set on the MG, and the MG maintains and summarizes the multicast group member information of all downstream flow interfaces. The first multicast group member database, and includes the following steps:

The MG receives the multicast group membership management protocol message from the downstream network on the downstream flow interface, and reports it to the MGC;

The MGC updates the content in the second multicast group member database maintained on the MGC according to the multicast group member management protocol message, and judges whether the second multicast group member database changes, and if so, instructs the MG on the upstream flow interface Sending a multicast group member management protocol message upstream to the upstream network; or, the MGC sends an indication to the MG of accepting the multicast group member management protocol message, and the MG updates the first multicast group member database according to the indication, and judges that the Whether the above-mentioned first multicast group member database changes, if so, then send a multicast group member management protocol message to the upstream network on the upstream flow interface;

or,

After the MG receives the query message on the upstream flow interface, it reports to the MGC. The MGC searches the contents of the second multicast group member database according to the query message. If a matching content is found, it indicates that the MG is in the upstream The flow interface sends a report message to the upstream network; or, after receiving the query message on the upstream flow interface, the MG searches the contents of the first multicast group member database, and if a matching content is found, then sends a report to the upstream network information.

The embodiment of the present invention also discloses a method for realizing the proxy of the multicast group member management protocol. Source address binding.

Yet another method for realizing multicast group member management protocol proxy disclosed by the embodiment of the present invention, in the multicast group member management protocol proxy, configure the multicast group address and/or multicast data flow between the upstream network and the downstream network The mapping relationship of the source address; and includes the following steps:

receiving a multicast group membership management protocol message at a downstream stream interface;

According to the mapping relationship, modify the multicast group address and/or multicast data flow source address of the downstream network in the multicast group member management protocol message to the multicast group address and/or group address of the mapped upstream network broadcast data flow source address;

sending the modified multicast group membership management protocol message on an upstream stream interface;

Alternatively, include the following steps:

A multicast stream is received on the upstream stream interface;

According to the mapping relationship, modify the multicast group address of the upstream network and/or the source address of the multicast data flow in the multicast data flow to the multicast group address and/or multicast data flow of the mapped downstream network source address, and then send the multicast data flow on the downstream flow interface.

The embodiment of the invention also discloses a system for realizing multicast group member management protocol proxy, including MG and MGC,

An upstream flow interface and at least one downstream flow interface are configured on the MG, and a multicast group membership database summarizing the multicast group membership information of all downstream flow interfaces of the MG is maintained; according to the multicast group membership database, the The multicast group membership management protocol message received by the upstream stream interface is forwarded to the corresponding downstream stream interface, or a report message is sent to the upstream stream interface;

The MGC is used to send a setting or updating command to the MG to set or update configurations on the MG.

The embodiment of the present invention discloses an MG, which includes a device for realizing the proxy function of the multicast group member management protocol, and the device includes:

An interface configuration module, configured to configure the interface connecting the MG to the packet subnet as an upstream flow interface or a downstream flow interface;

A multicast group database module, configured to maintain the total multicast subscription status of all downstream stream interfaces of the MG;

The agent forwarding module is used to search the content in the multicast group database module according to the query message received at the upstream flow interface, and if the matching content is found, send a report message to the upstream network at the upstream flow interface; or , updating the content in the multicast group database module according to the multicast group member management protocol message received by the downstream flow interface, and judging whether the multicast group membership database has changed, and if so, sending to the upstream network on the upstream flow interface Send a multicast group membership management protocol message.

Another system for implementing multicast group member management protocol proxy disclosed in the embodiment of the present invention includes MG and MGC, the MG is configured with one upstream flow interface and at least one downstream flow interface, and the MG maintains and summarizes the group of all downstream flow interfaces. A first multicast group member database of broadcast group member information; the MG is used to receive a multicast group member management protocol message from a downstream network at a downstream flow interface, and report the multicast group member management protocol message to the MGC; The MG updates the first multicast group member database and/or sends a multicast group member management protocol message according to the instruction sent by the MGC; or, the MG is configured to report to the MGC after receiving the query message on the upstream stream interface, and send a report message to the upstream network at the upstream flow interface according to the instruction of the MGC;

The MGC maintains a second multicast group member database that summarizes the multicast group member information of all downstream flow interfaces; according to the multicast group member management protocol message reported by the MG and the content in the second multicast group member database Issue a corresponding instruction to the MG.

The embodiment of the present invention discloses an MGC, including:

A receiving module, configured to receive a multicast group member management protocol message reported by the MG;

The second multicast group database module is used to maintain the total multicast subscription status of all downstream stream interfaces of the MG; according to the multicast group member management protocol message received by the receiving module, the maintained multicast subscription status is carried out Update or search, and notify the multicast instruction issuing module of the update or search result;

The issuing module is configured to issue corresponding instructions to the MG according to the update or search results.

As can be seen from the above technical solutions, the present invention maintains the upstream stream interface and the downstream stream interface on the MG, and maintains a multicast group member database for recording multicast group member information. According to the multicast group member database, the Process or forward the multicast group membership management protocol message from the upstream flow interface or downstream flow interface, so that the MG realizes the function of the multicast group membership management protocol agent.

Description of drawings

Fig. 1 is a schematic diagram of networking of MG and MGC in the prior art;

Fig. 2 is a schematic diagram of an application scenario of the solution of the present invention;

FIG. 3 is a schematic diagram of another application scenario of the solution of the present invention;

Fig. 4 is the processing flowchart of realizing the proxy function in the direction from the downstream network to the upstream network according to the embodiment of the present invention;

Fig. 5 is the process flowchart of realizing the proxy function in the direction from the upstream network to the downstream network according to the embodiment of the present invention;

FIG. 6 is a schematic diagram of establishing a topological relationship according to an embodiment of the present invention;

Fig. 7 is a block diagram of the internal structure of the MG according to the embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further elaborated below in conjunction with the accompanying drawings.

The media gateway between IP networks can serve as an IGMP/MLD proxy entity, and a simple application scenario is shown in Figure 2. The border gateway MG between the IP network 1 and the IP network 2 acts as an IGMP/MLD agent, and maintains a multicast group member database summarizing the multicast group member information of all downstream flow interfaces of the MG in the MG. IP network 2 is the proxy network of MG. MG is elected as a querier in IP network 2, and can send query messages to IP network 2 and process IGMP/MLD report messages received from IP network 2 or leave the multicast group. message: MG acts as a host in IP network 1, receives report message or leave message from IP network 1, and updates the multicast group member database according to the report message or leave message, when the multicast group member database record changes It can send IGMP/MLD report messages and leave messages to IP network 1; respond to query messages sent by the querier in IP network 1 according to the contents of the multicast group member database.

There is a new multicast group member subscribing to multicast in G1IP network 2, and the host sends a report of joining multicast group G1. As a multicast queryer (querier) in IP network 2, MG receives the report, if the report message changes the member database records, it sends a report as a host in IP network 1, requesting to join the multicast group G1. The report is received by the multicast router in the IP network 1, and the information of joining the multicast group is forwarded to the root node of the multicast source tree or shared tree according to the existing multicast routing protocol. In Figure 2, if the multicast data source of the multicast group requested by the host on IP network 2 is in IP network 2, the MG may be able to directly receive the multicast data stream sent by the The multicast router obtains the multicast data flow. The MG forwards the multicast data flow to the IP network 2 according to the member database record and the multicast group member status on each downstream flow interface.

In addition, the multicast router receiving the MG report in IP network 1 may itself be an IGMP/MLD proxy, and the proxy acts as a multicast queryer (also a multicast router) in IP network 1 . The host in IP network 2 may itself be an IGMP/MLD proxy, and the proxy acts as a host supporting multicast in IP network 2 . In the above two cases, the IGMP/MLD proxies are actually connected in series, and one or more of the connected IGMP/MLD proxies may be MGs with the functions of the present invention.

IGMP/MLD proxies (see RFC4605) allow one upstream stream interface and one or more downstream stream interfaces. The upstream stream interface here can be for all multicast, and the same is true for most scenarios. However, if used in a slightly more complex network structure, an upstream interface may only be used for one or some multicast groups. However, for other one or some multicast groups, their upstream stream interfaces may be different. In more complicated cases, for the same multicast group, the upstream stream interface corresponding to the shared tree and the upstream stream interface of the source tree of different multicast sources may be different. If the IGMP/MLD proxy can obtain the multicast group, group If the relationship between the broadcast source address and the upstream flow interface is established, and the upstream flow interface is bound to the multicast group and/or the multicast source address, the IGMP report can be sent to the upstream flow interface corresponding to the multicast to which the report belongs. This is also an enhancement to the IGMP/MLD proxy function. As shown in Figure 3.

In addition, the IGMP/MLD proxy can also complete the proxy between IPv4 and IPv6 networks. To realize this function, it is necessary to perform mapping between IPv4 addresses and IPv6 addresses for the multicast group addresses and multicast source addresses of their respective networks. Even for IGMP/MLD proxies between IP networks of the same version, there are situations where the planning of the multicast group address and/or multicast source address is different between the upstream flow interface and the downstream flow interface. The IGMP/MLD proxy maintains The multicast group address mapping relationship and/or the multicast source address mapping relationship. And the mapping is implemented on the proxy IGMP/MLD protocol message and the multicast data flow. This is actually an enhancement of the IGMP/MLD proxy function.

Multiple downstream stream interfaces share the multicast data stream obtained by the upstream stream interface. The MG needs to maintain the multicast group membership database, and also maintain the multicast group membership status on each downstream flow interface, that is, maintain the multicast group membership information on each downstream flow interface. The multicast group membership status is also called multicast group subscription status in this document.

In fact, the above-mentioned MG needs the participation of the MGC to implement the IGMP/MLD proxy function. In the embodiment of the present invention, MG and MGC are used as the multicast group member management protocol proxy system, and the proxy system needs to realize the following three aspects of functions:

A. The attribute configuration function of the upstream flow interface and the downstream flow interface.

The upstream stream interface needs to be configured on the MG. A configured upstream flow interface may be applicable to all multicast groups and multicast source addresses, but may be bound to one or more specific multicast groups (may further include multicast source addresses). As shown in Figure 4. In addition, for each upstream flow interface, one or more or all allowable downstream flow interfaces other than itself may be configured. The MG does not process the request to join a multicast group from a non-downstream interface. If the MG has multiple interfaces on the same subnet it is connected to, only one of them is selected as the upstream flow interface or downstream flow interface.

This configuration can be updated by the MGC in real time.

B. Admission control and resource reservation.

The proxy system maintains relevant information about the multicast group address and/or multicast data flow source address that is allowed to be proxied for each downstream flow interface; this information includes the authority of the host that sends IGMP/MLD messages to the downstream flow interface, and the authority includes permission Which multicast groups to join, etc.; this information also includes the total service bandwidth of each downstream flow interface, the joined multicast groups, and/or the priority level of each multicast data flow source address. When the total bandwidth is insufficient, high-priority data streams are given priority. This function cannot be used in all IGMP versions. Early versions of IGMP stipulated that hosts can listen to report messages sent by other hosts and avoid sending repeated report messages.

C. Mapping between multicast group address and multicast data flow source address.

In some cases, the planning of the source address of the multicast data flow between the various IP networks connected to the MG is inconsistent. For example, as shown in Figure 2, the multicast data flow with the source address S2 in IP network The source address is mapped to S1, that is, after the media gateway receives the IGMP report requesting to join the multicast group G1 on IP network 2 and the source address of the multicast data flow is S2, when forwarding the IGMP report to IP network 1, it will send the The report message is transformed into an IGMP report requesting to join the multicast group G1, and the source address of the multicast data flow is S1. Or the multicast group address needs to be mapped, for example, the multicast group G2 in the IP network 2 is mapped to the multicast group G1 in the IP network 1 . Different IP networks connected to the MG may also run different protocols, for example, the group membership management protocol of the IPv4 network is IGMP, and the group membership management protocol of the IPv6 network is MLD. Its multicast group address and multicast source address obviously need to be mapped.

Therefore, the proxy system maintains multicast group address translation rules and/or multicast data flow source address translation rules between upstream and downstream flow interfaces. Establish a multicast group address mapping relationship and/or a multicast data flow source address mapping relationship between the IP network where the upstream flow interface is located and the IP network where the downstream flow interface is located.

The proxy system (including MG and MGC) learns the status of group members in each downstream network through the IGMP/MLD message from the IP network where the downstream flow interface is located (hereinafter referred to as the downstream network), and updates the member database. Send a report to the upstream flow interface when the database record changes or leave a multicast group membership management protocol message, and send a report message according to the membership database content when receiving a query message from the upstream interface. While performing the above work, admission control and mapping of multicast group addresses and/or multicast source addresses should also be performed.

According to the different functions of MG and MGC, the agent system is divided into the following two ways:

Method 1: Maintain the processing mechanism for IGMP/MLD on the MG, and maintain member database records according to the proxied IGMP/MLD messages. The configuration on the MG can also be set or updated by the MGC to the MG. The disadvantage of the purely static configuration scheme is that the update of the rules may not be real-time enough. If the user rights are modified, the multicast group address and multicast data flow source address mapping rules need to be updated, or the static configuration needs to be updated when the priority level of the multicast group changes, it is difficult to guarantee the real-time performance of the update, and many rules need to be updated. The MGC is generated using the information of the control layer or the service layer, so the MGC needs to have the function of setting or updating the configuration on the MG.

Method 2: Through interaction with the MGC, the IGMP/MLD message is processed under the control of the MGC, including the MG reporting the received IGMP/MLD message and/or the MGC instructing the MG to send the IGMP/MLD message. In the scenario where the MG acts as an IGMP/MLD proxy, the MGC instructs the MG to detect report query messages on the upstream stream interface, and instructs the MG to send report messages and leave multicast group messages. The MGC instructs the MG to detect report messages and leave multicast group messages on the downstream flow interface, and send query messages.

The above two methods can also be used in combination. For example, some functions can be automatically completed on the MG through mode one configuration, such as periodic query on the downstream interface, automatic response to the query message on the upstream flow interface, etc. Some configurations can also be updated through the MGC instruction, such as the synchronization between the MGC and the MG The status of multicast group members on the downstream stream interface, and some functions can be reported by the MGC and sent IGMP/MLD messages by the MGC controlling the MG through the second method.

The first embodiment of the agent system adopts the scheme of the above-mentioned mode 1, and there are many feasible specific schemes, only one of which is described here, and the principle of other schemes is similar.

Extensions to the H.248 protocol, including:

1. Define an H.248 package impp for MGC setting or updating rules.

The MG as an IGMP/MLD proxy is located at the junction of two or more IP networks.

Define properties in the immp package:

(1). Upstream interface name (usin), the data type is octstring, the default value is empty, and its value is the interface name of the upstream interface;

(2). Downstream interface name (downstream interface name, dsin), the data type is octstringlist, the default value is empty, and its value is the interface name list of available downstream interface, because there may be more than one downstream interface, so use list to represent.

The name of the upstream flow interface represents the IP network where the upstream flow interface connected to it is located, and the name of the downstream flow interface represents the IP network where the available downstream flow interface connected to it is located.

The above attribute definition method is applicable to all multicast groups by default, that is, all multicast groups proxied by the proxy system use the same upstream flow interface and downstream flow interface. If different multicast groups or different multicast data flow source addresses can use different upstream flow interfaces and downstream flow interfaces, for example: one interface is the upstream flow interface of multicast group G1, and the other interface is multicast group G2 or, one interface is a multicast upstream interface of multicast group G1 with a multicast source address of S1, and the other interface is a multicast upstream interface of multicast group G1 with a multicast source address of S2, Then the above two attribute definition methods need to be further enhanced, including the multicast group identifier and/or the source address of the multicast data flow, and the upstream stream interface and available List of downstream stream interfaces.

It is also possible not to limit the downstream flow interface, that is, allow all interfaces except the upstream flow interface to be downstream flow interfaces.

The above upstream flow interface name and downstream flow interface name parameters can be replaced by the identification attribute of the IP network connected to the interface, and this parameter can refer to the expression indicated by the IP field in H.248.41. Its function is the same as using the interface name. All subsequent references to interface names can be replaced by IP domain identifiers.

2. Define the admission and reserve (admission and reserve, aar) signal, which is used for the MGC to update the admission control and resource reservation related configurations to the MG.

The signal defines the following parameters:

(1). Interface name (interface name, in), the data type is octstring, the default value is empty, and its value is the interface name.

(2). Allowed multicast group (allowed group, ag), the data type is string, the default value is empty, and its value is the allowed multicast group address, which may be an IPV4 address or an IPV6 address.

(3). The rejected group (ag), the data type is string, the default value is empty, and its value is the rejected multicast group address, which can be an IPV4 address or an IPV6 address.

(4). The multicast group that allows users to join (user agreed group, uag), the data type is string, the default value is empty, and its value is the source address of the request message and the group that is allowed to join. Between the two contents, use separated by commas.

(5). The multicast group that the user refused to join (user refused group, urg), the data type is string, the default value is empty, and its value is the source address of the request message and the group that was refused to join. separated by commas.

(6). Multicast group priority (group class, gc), the data type is octstring, the default value is empty, and its value is the group address and the corresponding priority.

When the MGC sends this signal to the MG, it is used to indicate the allowed and denied multicast groups on a certain interface, the authority setting of this interface for a certain user, and the priority level of each multicast group on this interface.

3. Define the signal gasamap, which is used by the MGC to update the mapping relationship between the multicast group address and the source address of the multicast data flow to the MG.

The signal defines the following parameters:

(1). Interface name (interface name, in), the data type is octstring, the default value is empty, and its value is the interface name of the downstream flow interface.

(2). The mapping between downstream address and upstream address (downstream address to upstream address, datoua), the data type is string list, the default value is empty, and its value is the multicast group address on the downstream interface and its mapped upstream The multicast group address on the stream interface. The two items are separated by commas. Each line in the list represents a mapping relationship.

(3). The mapping between the downstream multicast source and the upstream multicast source (downstream source to upstream source, datoua), the data type is string list, the default value is empty, and its value is the multicast data flow source on the downstream interface The address and the source address of the multicast data stream on the upstream stream interface to which it is mapped are separated by commas. Each line in the list represents a mapping relationship.

When the MGC sends this signal to the MG, it is used to indicate the multicast group address and/or the source address of the multicast data flow on the IP network where a certain downstream flow interface is located and the multicast group address and/or the multicast group address and/or the IP network where the upstream flow interface is located Or the correspondence between the source addresses of multicast data streams.

Through the above signals and attributes, the MGC instructs the MG to set or update the processing rules for IGMP/MLD messages. These signals and attributes can be set on the ROOT terminal of the MG, and can also be set on the non-ROOT terminal. If it is created on a non-ROOT terminal, you can specify the interface through the parameter in described above when creating the terminal. After specifying the interface, the terminal is used to process (including sending and receiving, etc.) the interface specified when the terminal is created IGMP/MLD messages in the connected IP network.

In addition, the query mechanism on the downstream stream interface needs to be explained. If the downstream stream interface receives the message of quitting the multicast group, it needs to send a query message to determine whether there are other users of the multicast group on the downstream network. There is a periodic query mechanism on the downstream stream interface to avoid the loss of multicast group member management protocol messages in the IP network, or the hosts in the downstream network leave the network before sending out the exit multicast group message, resulting in multicast on the downstream stream interface. The subscription status of group users does not match that of the actual network. In addition, if a query message is received on the upstream flow interface, in addition to the mechanism of searching the member database, a query message can be sent to the downstream flow interface to update the membership database and the multicast group subscription status on the downstream flow interface in time.

The maintenance of the member database and the status of the multicast group members on each downstream interface is based on the status of each multicast timer in addition to the report message and leave message received on the downstream flow receiver. It has been received before and will not be repeated here.

In IGMP v2, there are report messages for joining a multicast group and leave messages for leaving a multicast group. In IGMP v3, the functions of report message and leave message are realized through report message. For example, in the report message, the source address filter condition is MODE_IS_INCLUDE, but the source address list is empty, which actually means leaving the multicast group. In this way, one report message of IGMP v3 can realize multiple report messages and leave messages of IGMP v2 function.

The second embodiment of the proxy system adopts the solution of the second mode above, that is, through the interaction between the MG and the MGC, the IGMP/MLD messages are processed under the control of the MGC.

In the second embodiment, the configuration or designation of the upstream flow interface and the downstream flow interface can still use the method of the first embodiment.

On the downstream stream interface, the MGC sets the H.248 event detection IGMP/MLD report message and/or the message of leaving the multicast group to the MG. The MGC instructs the MG to send an IGMP/MLD query message through a signal. The following uses the IGMP protocol as an example, and the implementation of the MLD protocol is similar.

The H.248 events include:

1. Event igmprl that processes IGMP protocol messages.

The event igmprl is used to detect IGMP membership report (Membership Report) messages and leave group (Leave Group) messages.

The event has the following parameters:

(1) Interface name (interface name), the data type is octstring list, the default value is empty, and its value is the interface name list of the downstream flow interface to detect the event.

If this event is set on the root terminal, this parameter can be used to indicate on which or which downstream stream interfaces to detect IGMP report messages and leave group messages. If the value of this attribute is empty, it means to perform detection on all downstream flow interfaces.

If the event is set on a temporary terminal and the terminal is assigned an interface, this parameter does not need to be set.

The event is reported with the following parameters:

(1) The parameter (interface name, in), the data type is octstring list, and its value is the interface name of the downstream flow interface where the event is detected.

If the event occurs on a temporary terminal and the terminal is assigned an interface, this parameter does not need to be reported.

(2) Protocol version (ver), the data type is integer, the default value is 3, and its value is the protocol version, 1, 2, and 3 represent IGMP versions 1, 2, and 3, respectively.

(3) Message type (type), the data type is integer, the default value is 1, and its value represents the message type. 1 represents the IGMP report message, and 2 represents the IGMP leave group message.

(4). Report content (r1), the data type is string list, the default value is empty, and the value represents the content of the report message. Each row in the list represents the report content for a group. For IGMP V1 and IGMP V2, the content of each line is the group address of a multicast group. For IGMP V3, it's a bit more complicated. The format of each line in the list is as follows:

Multicast group address, type, source address 1, source address 2, ...

Types include the following:

MODE_IS_INCLUDE 1

MODE_IS_EXCLUDE 2

CHANGE_TO_INCLUDE_MODE 3

CHANGE_TO_EXCLUDE_MODE 4

ALLOW_NEW_SOURCES 5

BLOCK_OLD_SOURCES 6

If a line in the string list of parameter r1 is "224.100.200.3,1,192.168.1.2,192.168.1.3"

It means to join the multicast group 224.100.200.3, the source address filter type is MODE_IS_INCLUDE, the source address list is 192.168.1.2 and 192.168.1.3, that is, it is required to join the multicast group 224.100.200.3, but the source address of the limited multicast data flow must be 192.168 .1.2 or 192.168.1.3.

(5) Leave group message (leave group, lg), data type is string list, default value is empty, its value represents the list of the multicast group that leaves, and each item in the list is a multicast group address.

On the downstream stream interface, the MG also sends IGMP/MLD query messages. The query message may be automatically sent periodically by the MG, or the MG may instruct the MG to send it periodically, or be sent after being triggered by other events on the upstream flow interface or the downstream flow interface. If the MGC instructs the MG to send IGMP/MLD query messages, the H.248 protocol needs to be extended. Or take IGMP as an example:

2. The event igmpre used for the MGC to instruct the MG to send an IGMP query message.

The event includes the following parameters:

(1). Interface name (interface name, in), the data type is octstring, the default value is empty, and its value is the interface name of the downstream flow interface. If this event is set on the root terminal, this parameter can be used to indicate on which downstream stream interface to send the IGMP query message. If the signal is sent on a non-ROOT terminal and the terminal is assigned an interface, this parameter does not need to be set.

(2). Version (ver), the data type is integer, the default value is 3, and its value is the protocol version. 1, 2, and 3 represent IGMP versions 1, 2, and 3, respectively.

(3). Waiting time (mrc), the data type is integer, the default value is empty, and the value represents the Max Resp Code field in the query message. Indicates the maximum time to wait for a response report.

(4). Multicast group address (ga), the data type is string, the default value is empty, and the value represents the multicast group address in the query message.

(5). Multicast source address list (sal), the data type is string list, the default value is empty, and the value represents the multicast source address list in the query message.

After receiving the igmpre signal from the MGC, the MG constructs and sends an IGMP query message according to the parameters in the signal.

On the upstream flow interface, the H.248 protocol also needs to be extended. The MGC instructs the MG to send IGMP/MLD report messages and messages about leaving the multicast group, and when receiving query messages from upstream routers, the MG reports to the MGC. This requires the MGC to maintain the multicast group member database so that it can generate a report message when it receives a query message.

Events extended on the upstream streaming interface include:

1. The signal mrl is used by the MGC to instruct the NGW to send an IGMP report message and a leave group message on the upstream flow interface.

This signal includes the following parameters:

(1). The parameter interface name (interface name, in), the data type is octstring, and its value is the interface name of the upstream flow interface.

If the signal is sent to the root terminal, this parameter can be used to indicate on which upstream stream interface to send the IGMP report message. If the signal is sent to a specially created temporary terminal and the terminal is created on the specified interface, then this parameter does not need to be set. If the MG has only one upstream stream interface for all multicast groups, this parameter does not need to be set.

(2). Version (ver), the data type is integer, the default value is 3, and its value is the protocol version. 1, 2, and 3 represent IGMP versions 1, 2, and 3, respectively.

(3). Message type (type), data type: integer, the default value is 1, and its value represents the message type. 1 represents the IGMP report message, and 2 represents the IGMP leave group message.

(4). Report content (r1), the data type is string list, the default value is empty, and the value represents the content of the report message. Each row in the list represents the report content for a group. For IGMP v1 and IGMP v2, the content of each line is the group address of a multicast group. For IGMP v3, it's a bit more complicated. The format of each line in the list is as follows:

Multicast group address, type, source address 1, source address 2, ...

Types include the following:

MODE_IS_INCLUDE 1

MODE_IS_EXCLUDE 2

CHANGE_TO_INCLUDE_MODE 3

CHANGE_TO_EXCLUDE_MODE 4

ALLOW_NEW_SOURCES 5

BLOCK_OLD_SOURCES 6

If a line in the string list of the parameter r1 is "224.100.200.3, 1, 192.168.1.2, 192.168.1.3", it means joining the multicast group 224.100.200.3, the source address filtering type is MODE_IS_INCLUDE, and the source address list is 192.168.1.2 and 192.168.1.3, that is, it is required to join the multicast group 224.100.200.3, but the source address of the limited multicast data flow must be 192.168.1.2 or 192.168.1.3.

(5). Leaving group message (lg), the data type is string list, the default value is empty, and its value represents the list of the leaving multicast group, and each item in the list is a multicast group address.

The report message and the leaving group message can also be sent through two different signal instructions. The previous method is to use the same signal to send, and use parameters to distinguish the message type.

2. Extend the H.248 event rq, through which the MG reports the IGMP query message received at the upstream stream interface.

The event has the following parameters:

(1). Interface name (interface name, in), the data type is octstring, and its value is the interface name of the upstream flow interface.

If the event is set to the root terminal, this parameter can be used to indicate on which upstream stream interface to detect IGMP query messages. If the signal is sent to a temporary terminal and the terminal is assigned an interface, this parameter does not need to be set. If the MG has only one upstream stream interface for all multicast groups, this parameter does not need to be set.

The event is reported with the following parameters:

(1). Interface name (interface name, in), the data type is octstring list, and its value is the interface name of the upstream flow interface that detected the event. If this event is set on a non-ROOT terminal and the terminal is assigned an interface, or there is only one upstream flow interface on the MG, this parameter does not need to be reported.

(2). Version (ver), data type: integer, default value is 3, its value is the protocol version, 1, 2, 3 represent IGMP version 1, 2 and 3 respectively.

(3). Waiting time (mrc), the data type is integer, the default value is empty, and the value represents the Max Resp Code field in the query message. Indicates the maximum time to wait for a response report.

(4). Multicast group address (ga), the data type is string, the default value is empty, and the value represents the multicast group address in the query message.

(5). Multicast source address (sal), the data type is string list, the default value is empty, and the value represents the list of multicast source addresses in the query message.

In addition, some parameters need to be extended to carry other fields in the query message.

The MGC learns the IGMP query message received by the MG through this event, and performs subsequent operations, such as sending a report message.

Through the above-mentioned extended H.248 package, the MGC can control the MG to implement the function of acting as a proxy for the multicast group member management protocol. On this basis, it is possible to further realize the admission control of multicast group members and the multicast resource reservation function; and the multicast group address mapping function between the IP network where the upstream stream interface is located and the IP network where the downstream stream interface is located And multicast data flow source address mapping function.

Taking the proxy system composed of MGC and MG for processing in mode 2 as an example, the processing flow for realizing the proxy function in the downstream network is shown in Figure 4, including the following steps:

Step 401: The MG receives an IGMP/MLD report message or a message of leaving a multicast group on a downstream flow interface, and reports the received message to the MGC.

Step 402: The MGC judges whether it is necessary to update the member database through the locally configured policy, user subscription information, resource status, and records recorded in the multicast group member database maintained on the MGC, and if so, proceed to step 403; otherwise, the MGC Issue a rejection instruction to the MG, and end this process.

There may be many situations in judging whether to update the multicast group member database, and specific examples are given below to illustrate. For a report message requesting to join a multicast group, if the multicast group required by the report message has been recorded in the multicast group member database, there is no need to update the database; otherwise, it needs to be updated, that is, the multicast group record to the database; for a message requesting to leave a multicast group, it is necessary to send a specific group query message on the downstream interface receiving the message to determine that the multicast group to be left by the message is in the MG Whether there are other users subscribing to the downstream stream interface, if yes, the database does not need to be updated, otherwise it needs to be updated, that is, the record of the multicast group is deleted from the database.

The local policy on the MGC may include configuring the downstream flow interface on the MGC to allow the multicast group address and/or the multicast data flow source address list, and/or configuring the downstream flow interface to prohibit the multicast group address and/or multicast data A list of stream source addresses. Then the judgment in this step may include the following sub-judgments:

402A. The MGC judges whether the multicast group address and/or the source address of the multicast data flow carried in the report message or the message of leaving the multicast group is within the allowed multicast group address and/or the source address of the multicast data flow. list, or whether it is not in the prohibited multicast group address and/or multicast data stream source address list, if yes, continue to execute other sub-judgments; otherwise, the MGC sends a rejection instruction to the MG.

The local strategy on the MGC may also include configuring the total bandwidth allowed on the downstream flow interface on the MGC, and the priority of each multicast group and/or source address of the multicast data flow; then the judgment may include the following sub-judgments :

402B. Judging whether the sum of the multicast bandwidth corresponding to the report message and the existing multicast bandwidth of the downstream stream interface is greater than the total bandwidth allowed for access, if not, continue to execute other sub-judgments; according to the The priority judgment of the multicast group and/or multicast data flow source address carried in the report message whether to allow the multicast corresponding to the report message, if so, continue to execute other sub-judgments; otherwise, send a rejection instruction to the MG.

Step 403: Update the multicast group member database on the MGC.

Step 404: The MGC issues an instruction to the MG to send a report message or leave a multicast group message to the upstream network on the upstream stream interface.

In the above process, when forwarding the message to the upstream flow interface, since the content of the report message or the message leaving the multicast group sent to the upstream flow interface can be indicated by the MGC in the signal parameters, the MGC can instruct the MG to complete the upstream network and downstream network The multicast group address mapping function and the multicast data flow source address mapping function, that is, the multicast group address and/or multicast data source address in the message according to the downstream network planning are mapped to the multicast group according to the upstream network planning address and/or multicast data source address.

The processing flow of the proxy system to realize the proxy function in the upstream network is shown in Figure 5, including the following steps:

Step 501: After receiving the query message on the upstream stream interface, the MG reports the query message to the MGC;

Step 502: The MGC searches the contents of the multicast group member database according to the query message. If there is a mapping relationship between the multicast group address and/or the multicast source address between the upstream network and the downstream network, the MGC also needs to search for the contents of the multicast group membership database. Considering that, for example, the addresses of both parties that need to be matched can be unified into the same network; if the matching content is found, then step 503 is executed;

Step 503: The MGC instructs the MG to send a report message to the upstream network on the upstream stream interface;

The processing flow according to the first mode can refer to the above-mentioned flow in Fig. 4 and Fig. 5, the difference is that the interaction between the MG and the MGC is omitted, and the processing on the MGC is transferred to the MG for completion.

According to the report message and leaving multicast group message received on the downstream flow interface, the MG can maintain the multicast group membership status on the downstream flow interface, but the MGC may reject the downstream network user's request to join the multicast group due to reasons such as user rights. If the subscription status of multicast group users on each downstream interface is maintained on the MG, and the request to join the multicast group reported by the user is rejected, the MGC needs to indicate to the MG to prevent the MG from mistakenly updating the multicast group on the downstream interface Subscription status. There are two ways to indicate:

1. When the MG reports the event and reports to the MGC that the user joins the multicast group, the MGC returns an error code in the response message, indicating that the user is not allowed to join;

2. The MGC indicates to reject the previously reported request to join the multicast group through a signal carried in another message.

There is another way to ensure that the MG maintains the correct subscription status of multicast group users on each downstream flow interface. The MGC can also obtain the multicast group subscription status on each downstream flow interface according to the received message of joining a multicast group and leaving a multicast group reported by the MG. After the policy control of the MGC, some multicast subscriptions may be rejected These rejected multicast subscription requests are not used to update the multicast group subscription status on the downstream stream interface, nor are they used to update the membership database. The MGC can also obtain the multicast group subscription status of the hosts in the downstream network through the information obtained in the signaling flow of the service layer or the application layer. When the subscription status of the multicast group on the downstream stream interface changes, the MGC can update the MG through an extended H.248 message. The updated information includes the multicast group joined on the interface, source address filter conditions, and source address list. The extension method is relatively simple and will not be described in detail here.

The MG maintains the subscription status of multicast group users on each downstream flow interface. The MG can further derive the records of the multicast group membership database based on these information. Then, when receiving the query message on the upstream flow interface, it can automatically answer , without reporting to the MGC, and waiting for an instruction from the MGC to respond. When the multicast group member database on the MG changes, it actively sends a report message or a leave multicast group message to the upstream flow interface.

If the MGC maintains the multicast group address mapping relationship and/or multicast data stream source address mapping relationship between the upstream network and the downstream network, the MGC can extend the H.248 protocol to The group address mapping relationship and/or the multicast data stream source address mapping relationship are also delivered to the MG, and the MG also needs to combine the mapping information to forward the multicast data stream according to the multicast group subscription status on each downstream interface. When forwarding the multicast data flow, if there is a mapping relationship between the multicast group address and/or the source address of the multicast data flow, the MG needs to modify the mapped address on the data flow according to the mapping relationship.

If the mapping relationship is relatively fixed, it can also be configured on the MG, and the MGC can update the configuration through an H.248 message.

The MG reports the received multicast group membership management protocol message to the MGC, which may generate a large number of message interactions. In fact, it can be optimized. For redundant messages, the MG does not need to report, for example, it will not affect the downstream flow interface. It may be considered unnecessary to report the message of multicast group member information on the Internet, because for this kind of message, the admission control result of the MGC will not affect the forwarding of the multicast data flow by the MG.

In addition, the mechanism for the MG to send query messages on the downstream flow interface may have several situations. If the downstream stream interface receives the message of quitting the multicast group, it needs to send a query message to determine whether there are other users of the multicast group on the downstream network. There can also be a periodic query mechanism on the downstream flow interface to avoid the loss of the multicast group member management protocol message in the IP network, or the host in the downstream network leaves the network before sending out the exit multicast group message, causing the downstream flow interface to fail. The subscription status of multicast group users does not match that of the actual network. In addition, if a query message is received on the upstream flow interface, in addition to the mechanism for searching the member database, a mechanism for querying the downstream flow can be added to update the member database and the multicast group subscription status on the downstream flow interface in time.

The two methods of configuration on the MG and MGC control described above are not mutually exclusive, but can be used together. For example, some functions can be configured automatically on the MG, and some configurations can be updated through the MGC instruction, and some functions can be reported by the MG under the control of the MGC and send IGMP/MLD messages through solution 2.

If the event defined in the present invention is not a permanent event, it needs to be set by the MGC to the MG. If it is a permanent event, the MG can automatically detect and report the event.

The method described above solves the related processing problems of the IGMP/MLD protocol on the upstream flow interface and the downstream flow interface. The MG also needs to process and forward related multicast data streams.

If the MGC sends the previously defined signals and events to the root terminal of the MG, after the MG receives the multicast data stream on the upstream flow interface, it will Broadcast subscription (subscription) status, and forward the multicast data flow to the downstream flow interface that needs to be forwarded. In addition, whether the MG serves as the querier of the downstream network is also a reference condition. If it is not a querier, it does not need to forward the multicast data flow. If it is necessary to map the multicast group address and/or source address of the multicast data flow between the IP network where the upstream flow interface is located and the IP network where the downstream flow interface is located, the purpose of the data flow should be modified accordingly when the data flow is forwarded Address (multicast group address) and/or source address of multicast data flow to conform to the mapping relationship.

As shown in Figure 6, if the MGC sends the above-defined signals and events to the temporary terminal of the designated interface on the MG, the terminal designated as the upstream flow interface is called the upstream flow interface terminal, and it will be designated as the downstream flow interface The terminal of is called the downstream stream interface terminal. These terminals can be placed in the same context, and the topological relationship is unidirectional from the upstream stream interface terminal to the downstream stream interface terminal.

According to the above scheme 1, the internal structure block diagram of MG is shown in Figure 7, including:

The interface configuration module 701 is configured to configure the interface connecting the MG to the packet subnet as an upstream flow interface or a downstream flow interface. The interface configuration module 701 may configure the interface connected to the packet subnet as an upstream flow interface bound to a specific multicast group address and/or multicast source address.

A multicast group database module 702, configured to store the total multicast subscription status of all downstream stream interfaces of the MG;

The proxy forwarding module 703 is configured to search the content in the multicast group database module 702 according to the query message received at the upstream flow interface, and if a matching content is found, send a report message to the upstream network at the upstream flow interface Or, update the content in the multicast group database module 702 according to the report message received by the downstream flow interface or the message leaving the multicast group, and judge whether the multicast group membership database changes, if so, in the upstream flow The interface sends report messages or leave multicast group messages to the upstream network.

The proxy forwarding module 703 may also include:

A subscription status recording unit, configured to record the multicast subscription status of each downstream stream interface of the MG;

The multicast data flow forwarding unit is used to find the corresponding downstream flow interface according to the content in the subscription status recording unit for the multicast data flow received by the MG upstream flow interface, and forward the multicast data flow to the downstream stream interface.

The access control module 704 is configured to configure a list of allowed multicast group addresses and/or multicast data flow source addresses on the downstream flow interface, or configure a list of forbidden multicast group addresses and/or multicast data flow source addresses on the downstream flow interface , according to the multicast group address and/or multicast data flow source address carried in the report message received by the downstream flow interface, determine whether to process the multicast group member management protocol message from the downstream flow interface, and if so, notify the The proxy forwarding module 703 performs corresponding processing.

The access control module 704 further includes:

The bandwidth control unit is used to configure the total bandwidth allowed to be accessed on the downstream flow interface, and judge whether the sum of the multicast bandwidth corresponding to the report message received by the downstream flow interface and the existing multicast bandwidth of the downstream flow interface is greater than the specified The total bandwidth allowed to be accessed, if not, then notify the agent forwarding module 703 to perform corresponding processing;

and / or,

A priority control unit, configured to configure the priority of each multicast group and/or multicast data flow source address, according to the priority of the multicast group and/or multicast data flow source address carried in the report message received by the downstream flow interface , to determine whether to notify the proxy forwarding module 703 to perform corresponding processing.

The address mapping module 705 is used to configure the mapping relationship between the multicast group address and/or the source address of the multicast data flow between the upstream network and the downstream network; and according to the configured mapping relationship, the multicast received by the downstream flow interface The multicast group address and/or multicast data flow source address in the group member management protocol message is modified to the multicast group address and/or multicast data flow source address of the upstream network; and the modified message is forwarded to the agent Module 703 forwards;

And/or, according to the mapping relationship, modify the multicast group address and/or multicast data flow source address in the multicast data flow received by the upstream flow interface to the multicast group address and/or multicast data flow of the downstream network source address of the data stream, and forward the modified multicast data stream to the agent forwarding module 703 for forwarding.

The configuration management module 706 is configured to set or update the configuration of the interface configuration module 701 , the access control module 704 or the address mapping module 705 according to a configuration or update command from the MGC.

The multicast group timer module 707 is used to maintain the multicast group timer, and according to the maintained multicast group timer, or the maintained multicast group timer and the multicast group members received by the proxy forwarding module 703 The management protocol message updates the contents of the multicast group membership database module 702 . The multicast group timer module 707 may maintain more than one timer, such as the aforementioned group membership interval timer, query interval timer, active report interval timer, and query response interval timer.

A query message sending module 708, configured to send a query message on a downstream stream interface when a preset trigger condition is met; the trigger condition includes:

The multicast group timer maintained in the multicast group timer 707 expires, specifically, the multicast timer can be a query interval timer or a query response interval timer;

And/or, a leave multicast group message is received on the downstream stream interface;

And/or, the proxy forwarding module 703 searches the content of the multicast group member database according to the query message received by the upstream stream interface, but no matching content can be found.

According to the above scheme two, the MGC in the embodiment of the present invention includes:

A receiving module, configured to receive a multicast group member management protocol message reported by the MG;

The second multicast group database module is used to maintain the total multicast subscription status of all downstream stream interfaces of the MG; according to the multicast group member management protocol message received by the receiving module, the maintained multicast subscription status is carried out Update or search, and notify the multicast instruction issuing module of the update or search result;

The issuing module is configured to issue corresponding instructions to the MG according to the update or search results.

Wherein, the second multicast group database module may also include a policy decision unit, which is used to update the group in the second multicast group member database module according to locally configured policies, user subscription information, resource status, or any combination of the above information. broadcast subscription status.

The MGC may further include an address mapping module configured to configure the mapping relationship between the multicast group address and/or the source address of the multicast data flow between the upstream network and the downstream network; and according to the configured mapping relationship, the MG The multicast group address and/or multicast data flow source address in the multicast group member management protocol message received by the reported downstream flow interface is modified to the multicast group address and/or multicast data flow source address of the upstream network, and Send the multicast group address and/or multicast data stream source address of the upstream network to the MG through the sending module.

The MLD protocol is similar to the IGMP protocol. IGMP report messages, leave group messages, and query messages are respectively related to MLD's Multicast Listener Report (Multicast Listener Report) message, Multicast Listener Done (Multicast Listener Done) message and multicast The listener query (Multicast ListenerQuery) message corresponds, and the content of the message is basically the same, the main difference is that the multicast group address and the source address are both IPV6 addresses, and the details of its implementation will not be described here.

The solution of the present invention expands the H.248 protocol to enable MG and MGC to form a multicast group member management protocol proxy system, configure upstream stream interfaces, downstream stream interfaces, and a multicast group member database, and enable MG to forward multicast messages and group members. broadcast data stream.

If the IGMP/MLD proxy is between IPv4 and IPv6 networks, running IGMP on one side and MLD on the other side, it will not work properly. If the configurations of the multicast group address and/or multicast source address on both sides of the IGMP/MLD proxy are inconsistent, mapping is required. For example, the request for the multicast group G1 on the downstream stream interface carries the multicast group address S1, and S1 is the address identifier in the downstream network address planning; on the upstream stream interface, the multicast group address must follow the upstream network The address plan of the multicast group is represented as S2 in the address plan of the upstream network, so S1 needs to be mapped to S2. The solution of the invention introduces address mapping, so that the IGMP/MLD agent can handle it correctly.

In addition, the solution of the present invention also introduces the admission control function, which filters the user's request to join the multicast group according to the user's authority, and the IGMP/MLD agent maintains the member database through the received multicast group member management protocol message, and for this purpose As the basis for sending multicast group member management protocol messages.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (37)

1. A method for realizing multicast group member management protocol agency, characterized in that, an upstream flow interface and at least one downstream flow interface are set on the media gateway MG, and MG maintains and summarizes the multicast of all downstream flow interfaces of the MG A multicast group member database of group member information, and includes the following steps: The MG receives the multicast group membership management protocol message from the downstream network at the downstream flow interface, and updates the contents of the multicast group membership database according to the multicast group membership management protocol message, and the MG judges the multicast group membership database Whether there is a change, if so, send a multicast group membership management protocol message to the upstream network on the upstream flow interface; or, The MG receives the query message on the upstream flow interface, searches the contents of the multicast group membership database according to the query message, and sends a report message to the upstream network through the upstream flow interface if a matching content is found. 2. The method according to claim 1, wherein the MG maintains the multicast group membership information on each downstream flow interface, the method further comprising: The MG receives the multicast data flow on the upstream flow interface, and forwards the multicast data flow to the corresponding downstream flow interface according to the multicast group member information on each downstream flow interface. 3. The method according to claim 1, wherein said setting an upstream stream interface and at least one downstream stream interface on the MG comprises: the set upstream stream interface and downstream stream interface are applicable to all multicast groups, Or bind to a specific multicast group and/or multicast source address. 4. method according to claim 1, is characterized in that, described multicast group membership management protocol message comprises Internet Group Management Protocol IGMP report message, and IGMP leaves multicast group message, and multicast listener finds the multicast of MLD Listener Report or MLD's Multicast Listener Complete message. 5. The method according to claim 1, characterized in that the method comprises: The MG periodically sends query messages on the downstream flow interface; Or, after receiving the leave multicast group message on the downstream flow interface, the MG sends a query message on the downstream flow interface; Alternatively, searching the content of the multicast group member database according to the query message, if no matching content is found, further includes: sending a query message on a downstream stream interface. 6. The method according to claim 1, wherein the downstream flow interface is configured on the MG to allow the multicast group address and/or the source address list of the multicast data flow, or the downstream flow interface prohibits the multicast group address and/or A list of multicast data flow source addresses; Then before updating the content in the multicast group member database according to the multicast group member management protocol message, it further includes: MG judging the multicast group address and /or multicast data stream source address, whether it is in the list of allowed multicast group addresses and/or multicast data stream source addresses, or whether it is not in the list of prohibited multicast group addresses and/or multicast data stream source addresses , if yes, perform the subsequent steps. 7. The method according to claim 1, characterized in that the total bandwidth allowed to be accessed on the downstream stream interface, and/or the priority of each multicast group and/or source address of the multicast data flow are configured on the MG; Then, before updating the content in the multicast group membership database according to the report message, it further includes: The MG judges whether the sum of the multicast bandwidth corresponding to the report message and the existing multicast bandwidth of the downstream flow interface is greater than the total bandwidth allowed for access, and if not, executes the subsequent steps; or, According to the priority of the multicast group and/or the source address of the multicast data stream carried in the report message, it is judged whether to allow the multicast corresponding to the report message, and if so, perform the subsequent steps. 8. The method according to claim 1, wherein the mapping relationship between the multicast group address and/or the source address of the multicast data flow between the upstream network and the downstream network is maintained on the MG; Then, before sending the multicast group member management protocol message to the upstream network on the upstream stream interface, it further includes: According to the mapping relationship, modify the multicast group address and/or multicast data flow source address of the downstream network in the multicast group member management protocol message to the multicast group address and/or multicast data flow of the upstream network source address. 9. The method according to claim 2, characterized in that, maintaining the mapping relationship between the multicast group address and/or the source address of the multicast data flow between the upstream network and the downstream network on the MG; Then the forwarding of the multicast data flow to the corresponding downstream flow interface includes: According to the mapping relationship, modify the multicast group address of the upstream network and/or the source address of the multicast data flow in the multicast data flow to the multicast group address and/or multicast data flow of the mapped downstream network source address, and then send the multicast data flow. 10. The method according to claim 8 or 9, wherein the address mapping relationship is conversion between addresses of the same IP version or mapping between addresses of different IP versions. 11. The method according to any one of claims 1 to 9, wherein the multicast group timer is maintained on the MG, and the updating of the contents in the multicast group member database comprises: according to the group The state of the multicast group timer, or the state of the multicast group timer and the multicast group member management protocol message update the contents of the multicast group member database. 12. The method according to any one of claims 1 to 9, characterized in that the method further comprises: the media gateway controller (MGC) sends a setting or updating command to the MG to set or update the configuration on the MG . 13. A method for realizing multicast group member management protocol proxy, characterized in that, an upstream stream interface and at least one downstream stream interface are set on the MG, and the MG maintains the first multicast group member information summarizing all downstream stream interfaces The multicast group member database, and includes the following steps: The MG receives the multicast group membership management protocol message from the downstream network on the downstream flow interface, and reports it to the MGC; The MGC updates the content in the second multicast group member database maintained on the MGC according to the multicast group member management protocol message, and judges whether the second multicast group member database changes, and if so, instructs the MG on the upstream flow interface Sending a multicast group member management protocol message upstream to the upstream network; or, the MGC sends an indication to the MG of accepting the multicast group member management protocol message, and the MG updates the first multicast group member database according to the indication, and judges that the Whether the above-mentioned first multicast group member database changes, if so, then send a multicast group member management protocol message to the upstream network on the upstream flow interface; or, After the MG receives the query message on the upstream flow interface, it reports to the MGC. The MGC searches the contents of the second multicast group member database according to the query message. If a matching content is found, it indicates that the MG is in the upstream The flow interface sends a report message to the upstream network; or, after receiving the query message on the upstream flow interface, the MG searches the contents of the first multicast group member database, and if a matching content is found, then sends a report to the upstream network information. 14. The method according to claim 13, wherein the MG maintains the multicast group membership information on each downstream flow interface, the method further comprising: The MG receives the multicast data flow on the upstream flow interface, and forwards the multicast data flow to the downstream flow interface according to the multicast group member information on each downstream flow interface. 15. The method according to claim 13, wherein the multicast group timer is maintained on the MG, and the MGC updates the second multicast group member maintained on the MGC according to the multicast group member management protocol message Content in the database further includes: The MG reports to the MGC that the multicast timer expires, and the MGC updates the content in the second multicast group member database according to the reported information; or, the MGC maintains the multicast timer, and the MGC further The status updates the content in the second multicast group membership database. 16. The method according to claim 13, the MG receives the multicast group member management protocol message from the downstream network at the downstream flow interface, and reports it to the MGC, wherein the MG only reports the message affecting the first multicast group member database The contents of the Multicast Group Membership Management Protocol message. 17. The method according to claim 13, characterized in that the MG receives the multicast group member management protocol message from the downstream network at the downstream flow interface, and reports it to the MGC, further comprising: the MGC according to the locally configured policy and user subscription information updating the content in the second multicast group member database, or indicating to the MG whether to accept the multicast group member management protocol message. 18. The method according to claim 13, further comprising: the MG periodically sends a query message on the downstream flow interface, or the MG sends a query message on the downstream flow interface according to the instruction of the MGC, or the MG receives a query message on the downstream flow interface. A query message is sent on the downstream stream interface after the message to leave the multicast group on the downstream stream interface. 19. The method according to claim 13, characterized in that, the mapping relationship between the multicast group address and/or the multicast data flow source address between the upstream network and the downstream network is maintained on the MGC or MG; Then the MG further includes: The MGC or MG modifies the multicast group address and/or multicast data flow source address in the multicast group member management protocol message to the multicast group address and/or multicast data flow of the upstream network according to the mapping relationship source address. 20. The method according to claim 14, wherein the mapping relationship between the multicast group address and/or the source address of the multicast data flow between the upstream network and the downstream network is maintained on the MG; Then the forwarding of the multicast data flow to the corresponding downstream flow interface includes: According to the mapping relationship, the MG modifies the multicast group address and/or multicast data flow source address in the multicast data flow to the multicast group address and/or multicast data flow source address of the downstream network, and then The MG sends the multicast data flow. 21. A method for implementing a multicast group member management protocol proxy, characterized in that the upstream flow interface of the multicast group member management protocol proxy is bound to a specific multicast group, or is bound to a specific multicast group and a multicast source address binding. 22. A method for implementing a multicast group member management protocol agent, characterized in that, in the multicast group member management protocol agent, configure the multicast group address and/or multicast data flow source between the upstream network and the downstream network The mapping relationship of the address; and includes the following steps: receiving a multicast group membership management protocol message at a downstream stream interface; According to the mapping relationship, modify the multicast group address and/or multicast data flow source address of the downstream network in the multicast group member management protocol message to the multicast group address and/or group address of the mapped upstream network broadcast data flow source address; sending the modified multicast group membership management protocol message on an upstream stream interface; Alternatively, include the following steps: A multicast stream is received on the upstream stream interface; According to the mapping relationship, modify the multicast group address of the upstream network and/or the source address of the multicast data flow in the multicast data flow to the multicast group address and/or multicast data flow of the mapped downstream network source address, and then send the multicast data flow on the downstream flow interface. 23. A system for implementing multicast group member management protocol agency, including MG and MGC, characterized in that, The MG maintains a multicast group membership database that summarizes the multicast group membership information of all downstream flow interfaces of the MG, configures one upstream flow interface and at least one downstream flow interface, and; according to the multicast group membership database, set The multicast group membership management protocol message received by the upstream stream interface is forwarded to the corresponding downstream stream interface, or a report message is sent to the upstream stream interface; The MGC is used to send a setting or updating command to the MG to set or update configurations on the MG. 24. The system according to claim 23, wherein the MG is further used to maintain the multicast group timer, according to the state of the multicast group timer, or the state of the multicast group timer and the downstream stream The multicast group membership management protocol message received by the interface updates the content of the multicast group membership database. 25. An MG, characterized in that it includes a device for implementing a multicast group membership management protocol proxy function, the device comprising: An interface configuration module, configured to configure the interface connecting the MG to the packet subnet as an upstream flow interface or a downstream flow interface; A multicast group database module, configured to maintain the total multicast subscription status of all downstream stream interfaces of the MG; The agent forwarding module is used to search the content in the multicast group database module according to the query message received at the upstream flow interface, and if the matching content is found, send a report message to the upstream network at the upstream flow interface; or , updating the content in the multicast group database module according to the multicast group member management protocol message received by the downstream flow interface, and judging whether the multicast group membership database has changed, and if so, sending to the upstream network on the upstream flow interface Send a multicast group membership management protocol message. 26. The MG according to claim 25, wherein the interface configuration module configures the interface connected to the packet subnet as an upstream flow interface bound to a specific multicast group address and/or multicast source address. 27. The MG according to claim 25, further comprising: The access control module is configured to configure a list of allowed multicast group addresses and/or multicast data flow source addresses on the downstream flow interface, or configure a list of forbidden multicast group addresses and/or multicast data flow source addresses on the downstream flow interface, According to the multicast group address and/or multicast data flow source address carried in the multicast group membership management protocol message received by the downstream flow interface, determine whether to process the multicast group membership management protocol message from the downstream flow interface, if so, Then notify the proxy forwarding module to perform corresponding processing. 28. The MG according to claim 27, wherein the access control module further comprises: The bandwidth control unit is used to configure the total bandwidth allowed to be accessed on the downstream flow interface, and judge whether the sum of the multicast bandwidth corresponding to the report message received by the downstream flow interface and the existing multicast bandwidth of the downstream flow interface is greater than the specified The total bandwidth of the above-mentioned allowed access, if not, then notify the agent forwarding module to carry out corresponding processing; and / or, A priority control unit, configured to configure the priority of each multicast group and/or multicast data flow source address, according to the priority of the multicast group and/or multicast data flow source address carried in the report message received by the downstream flow interface , judging whether to notify the proxy forwarding module to perform corresponding processing. 29. The MG according to claim 25, further comprising: a multicast group timer module, configured to maintain the multicast group timer, and according to the maintained multicast group timer, or the The maintained multicast group timer and the multicast group member management protocol message received by the agent forwarding module update the contents of the multicast group member database module. 30. The MG according to claim 29, wherein the MG further comprises: A query message sending module, configured to send a query message at a downstream stream interface when a preset trigger condition is met; the trigger condition includes: The timer maintained in the multicast group timer expires; A leave multicast group message is received on the downstream stream interface; Alternatively, the content of the multicast group member database is searched according to the query message received by the upstream stream interface, but no matching content can be found. 31. The MG according to any one of claims 25 to 30, wherein the proxy forwarding module further comprises: A subscription status recording unit, configured to record the multicast subscription status of each downstream stream interface of the MG; The multicast data flow forwarding unit is used to find the corresponding downstream flow interface according to the content in the subscription status recording unit for the multicast data flow received by the MG upstream flow interface, and forward the multicast data flow to the downstream stream interface. 32. The MG according to claim 35, further comprising: The address mapping module is used to configure the mapping relationship between the multicast group address and/or multicast data flow source address between the upstream network and the downstream network; and according to the configured mapping relationship, the multicast group received by the downstream flow interface The multicast group address and/or multicast data flow source address in the member management protocol message is modified to the multicast group address and/or multicast data flow source address of the upstream network, and the modified multicast group membership management protocol The message is sent to the proxy forwarding module; Or, according to the mapping relationship, modify the multicast group address and/or multicast data flow source address in the multicast data flow received by the upstream flow interface to the multicast group address and/or multicast data flow of the downstream network source address, and send the modified multicast data stream to the proxy forwarding module. 33. The MG according to any one of claims 25 to 30, characterized in that the MG further comprises: a configuration management module, configured to configure the interface module, access The configuration of the control module or the address mapping module is set or updated. 34. A system for implementing multicast group member management protocol proxy, including MG and MGC, characterized in that, the MG is configured with one upstream stream interface and at least one downstream stream interface, and the MG maintains and summarizes the multicast streams of all downstream stream interfaces The first multicast group member database of group member information; the MG is used to receive the multicast group member management protocol message from the downstream network at the downstream flow interface, and report the multicast group member management protocol message to the MGC; the MG Updating the first multicast group member database and/or sending a multicast group member management protocol message according to an instruction issued by the MGC; or, the MG is configured to report to the MGC after receiving the query message on the upstream stream interface, and sending a report message to the upstream network at the upstream flow interface according to the instruction of the MGC; The MGC maintains a second multicast group member database that summarizes the multicast group member information of all downstream flow interfaces; according to the multicast group member management protocol message reported by the MG and the content in the second multicast group member database Issue a corresponding instruction to the MG. 35. An MGC, characterized in that it comprises: A receiving module, configured to receive a multicast group member management protocol message reported by the MG; The second multicast group database module is used to maintain the total multicast subscription status of all downstream stream interfaces of the MG; according to the multicast group member management protocol message received by the receiving module, the maintained multicast subscription status is carried out Update or search, and notify the multicast instruction issuing module of the update or search result; The issuing module is configured to issue corresponding instructions to the MG according to the update or search results. 36. The MGC according to claim 35, wherein the second multicast group database module further comprises: A policy decision unit, configured to update the multicast subscription status in the second multicast group member database module according to locally configured policies, user subscription information, resource status or any combination of the above information. 37. The MGC according to claim 35 or 36, characterized in that the MGC further comprises an address mapping module configured to configure a multicast group address and/or a multicast data flow source between the upstream network and the downstream network Address mapping relationship; and according to the configured mapping relationship, modify the multicast group address and/or multicast data flow source address in the multicast group member management protocol message received by the downstream flow interface reported by the MG to the upstream network address The multicast group address and/or the source address of the multicast data stream, and send the multicast group address and/or the source address of the multicast data stream of the upstream network to the MG through the sending module.

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