WO2009039788A1

WO2009039788A1 - A method and apparatus of realizing multicast transmission

Info

Publication number: WO2009039788A1
Application number: PCT/CN2008/072449
Authority: WO
Inventors: Jianping Wu; Mingwei Xu; Yong Cui; Yuntao Zhou; Hui Liu; Wei Cao
Original assignee: Huawei Technologies Co., Ltd.; Tsinghua University
Priority date: 2007-09-20
Filing date: 2008-09-22
Publication date: 2009-04-02
Also published as: CN101394342B; CN101394342A

Abstract

A method and apparatus of realizing multicast transmission, and the method includes: when receiving multicast data needing to be transmitted across a network, the ingress PE determines the egress PEs matched with the multicast data according to the multicast address of the multicast data and the matching relationship between the multicast address and the corresponding egress PEs settled in the ingress PE; the said ingress PE encapsulates the multicast data respectively using each determined egress PE's address, and sends each encapsulated multicast data to the said each determined egress PE respectively in form of unicast through mid-transmission network. With the provided method and apparatus, in case of mid-transmission network not supporting multicast protocol, the multicast transmission using transitional multicast technology can be reached, it is not necessary for the great number of routers in the mid-transmission network to support multicast protocol, and the cost of realizing is reduced.

Description

Method and apparatus for realizing multicast transmission This application claims priority to Chinese Patent Application entitled "Method and Apparatus for Implementing Multicast Transmission", filed on September 20, 2007, by the Chinese Patent Office, Application No. 200710154643. The entire contents of this application are incorporated herein by reference.

Technical field

The present invention relates to the field of network communication technologies, and in particular, to a method and apparatus for implementing multicast transmission. Background technique

Currently, with the increasing number of network communication users, the traditional fourth-generation Internet Protocol (IPv4) network has been unable to provide sufficient address space for users to use, based on the sixth generation Internet Protocol (IPv6). The next generation network of Internet Protocol version 6 ) is rapidly evolving. However, since IPv4 networks already have considerable connectivity, and most of the current applications are designed and used in IPv4 networks, IPv4 networks will inevitably exist for a long time in the future. As a result, traditional IPv4 networks are currently formed. The transition phase of the next generation of IPv6 networks is gradually merging. In this transitional phase, with the gradual establishment of the IPv6 network as the backbone network and the gradual abandonment of the IPv4 network, there will be some cases where the IPv4 networks are not connected to each other and need to be interconnected through the intermediate IPv6 transmission network. Of course, correspondingly Some IPv6 networks are disconnected from each other and need to be interconnected through an intermediate IPv4 transport network. This will appear: Protocol (I-IP, Intra Network Internet Protocol) used as an intermediate transport network connecting multiple peripheral client networks and protocols used by peripheral customer networks (E-IP, Extra Network Internet Protocol) Different, that is, there will be a case where the I-IP is IPv4 and the E-IP is IPv6, or the I-IP is IPv6 and the E-IP is IPv4. The protocols used in the intermediate transport network and the peripheral customer network are different from each other, which may cause different peripheral customer networks to communicate with each other through the intermediate transport network.

In order to solve the problems that may occur in the above transition phase, the prior art proposes a multicast translation technology based on address translation. The basic idea of the technology is: at the Provider Edge router (PE), E The IP multicast control packet and the multicast data packet are respectively translated into an I-IP multicast control packet and a multicast data packet, where the PE is an edge router between the intermediate transport network and the peripheral client network; Then, the PE transmits the translated I-IP multicast packet to the I-IP network, and when the packet reaches the egress PE, the packet is restored to the corresponding E-IP multicast packet, and Will The text continues to be transmitted in the E-IP network. By transmitting the translated I-IP multicast message in the I-IP network, E-IP multicast data can be established on the transport network provider router (P, Provider router) of the I-IP network. The I-IP multicast tree of the transport service. An E-IP multicast tree corresponds to an I-IP multicast tree in the I-IP network. These two multicast trees are essentially different representations of the multicast tree in different protocols. The translation adopts a pre-agreed unified format, so that each PE can be identified, so that mutual negotiation between the PEs is not required.

The above translation process is described in detail below. For example, when the protocol running on the intermediate transport network is IPv6 and the protocol running on the peripheral client network is IPv4, the format of the translation is as shown in FIG. 1 , where the IPv6 prefix is a specific IPv6 address prefix, so that the PE receives the IPv6 prefix. After the address, it can be handed over to the corresponding restore module for processing. The specific address prefix can be obtained through address allocation or internally configured by an Internet Service Provider (ISP). The translation and restoration process is as follows:

Translation: The part of the destination network address in the IPv4 unicast or multicast routing table, in the form a.b.c.d/M, where M is the bit length of the mask. According to the 4over6 address mapping, it can be transformed into a pseudo IPv6 address: 4over6prefix: a.b.c.d /len+M. 4over6prefix/len is a pseudo-IPv6 address-specific prefix with a length of len. The pseudo-IPv6 address-specific prefix can be obtained through address allocation, or can be allocated and managed by an ISP, so that all PEs can be identified without negotiation.

Restore: The 4over6 border router uses the pseudo IPv6 address prefix 4over6prefix/len to prefix match the destination address. If the prefix within the len prefix length is the same, then the IPv6 route is determined to be a pseudo IPv6 route, and then the inverse transform of the 4over6 route conversion is performed. Perform a route restore.

Although the above multicast transition technology can realize the network communication of the peripheral customer network through the intermediate transmission network under the condition that the I-IP and the E-IP are different, the technology can only be applied to the case where the intermediate transmission network supports the unicast data transmission. If you need to carry out multicast transmission through the intermediate transmission network, all routers including PE and a large number of P routers in the intermediate transmission network need to support the multicast protocol. In practical applications, it is often due to funds, manpower, technology, etc. For the reason, the intermediate P router in the intermediate transmission network does not support the multicast protocol, so that the multicast transition technology cannot be applied if the intermediate transmission network does not support the multicast protocol, thereby causing I-IP and E- When the IP is different, the peripheral customer network cannot be multicasted through the intermediate transmission network.

In addition, in the above prior art, in order to be different in the case where I-IP and E-IP are different, The network of the customer network is transmitted through the intermediate transmission network, and translation of different network protocols is required. When the E-IP protocol type is IPv4 and the I-IP protocol type is IPv6, the IPv4 address of the E-IP is translated into I-IP. The IPv6 address is relatively easy. Since the IPv6 address has 128 bits, the translation can be combined with a 32-bit IPv4 address and a 96-bit specific IPv6 prefix to form a 128-bit pseudo IPv6 address. However, when the E-IP protocol type is IPv6. When the I-IP protocol type is IPv4, the IPv4 address is 128 bits and the IPv4 address is 32 bits. Unless a complex inter-PE address negotiation mechanism is added, or a specific domain is added to the protocol, the 128-bit IPv6 address cannot be obtained. Translated into a 32-bit IPv4 address, which makes the technical solution more complicated to implement. In addition, since translation and restoration need to follow pre-established rules, and the routing of I-IP multicast control messages obtained by E-IP translation in the I-IP network needs to add an additional addressing mechanism, I - The intermediate P router of the IP transport network also needs to support this addressing mechanism accordingly, which also brings great difficulty in implementing the above-mentioned prior art implementation.

Summary of the invention

It is an object of embodiments of the present invention to provide a method and apparatus for implementing multicast transmission so that multicast transmission can be implemented using a multicast transition technique even if the intermediate transmission network does not support a multicast protocol.

In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:

A method for implementing multicast transmission, the method comprising:

When the multicast data received by the ingress Provider edge router PE needs to be transmitted across the transport network, the corresponding relationship between the multicast address of the multicast data and the multicast address established on the ingress PE and the corresponding egress PE Determining, respectively, respective egress PEs that match the multicast data;

Encapsulating the multicast data by using the determined addresses of the egress PEs, and transmitting the encapsulated multicast data to the determined egress PEs through the intermediate transport network in a unicast manner .

An apparatus for implementing multicast transmission, the apparatus comprising: a peripheral client network processing module, an intermediate transmission network processing module, and an intermediate transmission network transmission module, wherein:

The peripheral client network processing module is configured to: when determining that the received multicast data needs to be transmitted across the intermediate transmission network, send the multicast data to the intermediate transmission network processing module;

The intermediate transmission network processing module is configured to: establish, according to the multicast address of the multicast data, and establish Corresponding relationship between the multicast address and the egress PE, determining each egress PE that matches the multicast data, and encapsulating the multicast data by using the determined address of each egress PE; The intermediate transmission network transmission module is configured to: send each multicast data encapsulated by the intermediate transmission network processing module to the determined outlet PEs through the intermediate transmission network in a unicast manner.

It can be seen that, in the embodiment of the present invention, the multicast address established by the ingress PE and the corresponding egress are

The corresponding relationship between the PEs and the corresponding outgoing PEs that need to be sent to the multicast data that is currently sent, and the multicast data is encapsulated according to the determined egress PE, and the encapsulated multicast data is separately unicasted. The mode is sent to the egress PE, so that when the intermediate transmission network does not support the multicast protocol, the multicast transition technology can also be used to implement multicast transmission, and in the specific implementation process, only the intermediate transmission network needs to be located. The PE router at the edge of the peripheral customer network supports the multicast mechanism. It does not require a large number of P routers in the middle of the intermediate transmission network to support the multicast protocol, which makes the solution easier to implement and can reduce the implementation cost.

In addition, in the implementation process of the embodiment of the present invention, the translation of the different network protocol addresses is not required, and the implementation of the embodiment of the present invention is further simplified, thereby facilitating the rapid promotion of the multicast service. DRAWINGS

1 is a translated format used in the translation of different network protocols in the prior art; FIG. 2 is a flowchart of a method according to an embodiment of the present invention;

FIG. 3 is a flowchart of establishing a correspondence between the multicast address and a corresponding egress PE on an ingress PE according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of deleting the multicast address and corresponding exit on an ingress PE according to an embodiment of the present invention.

Flowchart of the correspondence of PEs;

FIG. 5 is a schematic diagram of an apparatus according to an embodiment of the present invention.

detailed description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Referring to FIG. 2, in an embodiment of the present invention, implementing multicast transmission includes the following steps:

Step 201: The ingress service provider edge router (PE) receives the multicast data; and determines whether the received multicast data needs to be transmitted across the network. If necessary, step 202 is performed; otherwise, the multicast data is transmitted in the network.

Step 202: The ingress PE is based on the multicast address of the multicast data, and on itself Corresponding relationship between the established multicast address and the corresponding egress PE, and determining each egress PE that matches the multicast data;

Step 203: The ingress PE separately encapsulates the multicast data by using the determined addresses of the egress PEs, and sends the encapsulated multicast data to the office through the intermediate transmission network in a unicast manner. The respective outlet PEs are determined.

In a preferred embodiment of the present invention, after receiving the multicast data, each of the egress PEs may further decapsulate the encapsulated multicast data, and further perform the decapsulated multicast data. Forward until the data transfer is completed.

The ingress PE uses a multicast forwarding entry to store and maintain the correspondence between the multicast address and each egress PE. For the convenience of description, in the following embodiments, the multicast forwarding item is taken as an example to provide an embodiment of the present invention. The method is described; of course, in other embodiments of the present invention, other manners may be used to save and maintain the correspondence between the multicast address and the egress PE set, without affecting the implementation of the present invention.

For the sake of clarity, the following is a description of how to establish and delete the correspondence between the multicast address and the egress PE on the ingress PE for the client of the peripheral client network to join the multicast group and exit the multicast group. In detail, the ingress and egress are both for the flow of multicast data transmission, and not for the "3⁄4" flow direction when establishing and maintaining the correspondence.

(―) The client of the peripheral client network joins the multicast group:

Referring to FIG. 3, in an embodiment of the present invention, when a client of a peripheral client network joins a multicast group, establishing a correspondence between the multicast address and the corresponding egress PE on the ingress PE includes the following steps:

Step 301: A client client that requests to join the multicast group, and sends a request in the E-IP format to the egress PE that is directly connected to the peer network through the peripheral client network. The join packet carries the group. Broadcast address, the multicast address includes the address of the multicast source in the multicast group to which the client is to join, and the address of the multicast group to which the client wants to join; for convenience of presentation, the join(s, g) indicates a join message, where s represents an address of the multicast source, and g represents an address of the multicast group;

Step 302: The egress PE determines, according to the unicast routing table, that the address s of the multicast source is located in an E-IP network connected to an ingress PE at the other end of the intermediate transmission network, and the join (s, g) encapsulate the I-IP address with the egress PE, and pass the encapsulated packet through the intermediate transmission network in unicast mode. Sending to the inlet PE of the other end;

Step 303: The ingress PE receives the encapsulated join(s, g) packet, decapsulates the packet, and performs the following processing according to the multicast address (s, g) in the packet:

If the correspondence between the multicast address ( s, g ) in the join (s, g) and the corresponding egress PE is already existing, the information about the egress PE obtained after decapsulation is added to the multicast address and Corresponding relationship between the egress PE and the multicast address corresponding to the multicast group client is established in the corresponding relationship of the egress PE; when the multicast forwarding entry is used to save the correspondence, the foregoing processing is: If it is determined that the multicast forwarding entry entry((s, g), {PE}) corresponding to the multicast address (s, g) in the join(s, g) already exists, the packet is decapsulated. The I-IP address of the egress PE is added to the PE set {PE} of the forwarding entry;

If there is no corresponding relationship between the multicast address ( s, g ) in the join (s, g) and the corresponding egress PE, the corresponding relationship is established on the ingress PE; When the corresponding relationship is saved, the foregoing processing is: if there is no multicast forwarding entry corresponding to the multicast address (s, g) in the join (s, g), then A multicast forwarding entry ((s, g), {PE}) corresponding to the multicast address (s, g) is established on the ingress PE, and the I-IP address in the multicast forwarding entry PE set {PE} is set. Initialized to the I-IP address of the egress PE.

Further, when the client of the peripheral client network joins the multicast group, the embodiment of the present invention may further include the following steps:

The ingress PE forwards the join(s, g) message to the next hop client edge (CE) router, and the CE router further completes the registration process of the client joining the multicast group.

(2) The client of the peripheral customer network exits the multicast group:

Referring to FIG. 4, in an embodiment of the present invention, in the case that the client of the peripheral client network requests to exit the multicast group, the corresponding relationship between deleting the multicast address and the corresponding egress PE on the ingress PE includes the following steps:

Step 401: The peripheral client network client requesting to leave the multicast group sends a request quit message in the E-IP format to the egress PE directly connected to the multicast client network; the packet also carries the join text. Similar to the multicast address, the request is logged out as quit(s, g);

Step 402: The egress PE determines, according to the unicast routing table, that the address s of the multicast source is located in an E-IP network connected to the ingress PE of the other end of the intermediate transmission network, and the quit(s, g) Encapsulating the I-IP address of the egress PE, and sending the encapsulated packet to the ingress PE of the other end through the intermediate transmission network in a unicast manner;

Step 403: The ingress PE receives the encapsulated quit(s, g) packet, decapsulates the packet, and performs the following processing according to the multicast address (s, g) in the packet:

The mapping between the multicast address corresponding to the multicast address (s, g) in the quit (s, g) and the egress PE is obtained, and the information of the egress PE obtained by decapsulation is in the corresponding relationship. Delete. When a multicast forwarding entry is used to save the corresponding relationship, the above processing is:

The multicast forwarding entry entry((s, g), {PE}) corresponding to the multicast address (s, g) in the quit(s, g) is obtained, and the egress PE obtained after decapsulation is obtained. The I-IP address is deleted from the PE set {PE} of the forwarding entry, thereby deleting the correspondence between the egress PE and the multicast address corresponding to the request to exit the multicast group client; further, if collecting from the PE After the I-IP address of the egress PE is deleted, the PE set is an empty set, and the multicast forwarding entry ((s, g), {PE}) may be further deleted to save the storage space of the PE.

In addition, in the actual application, the correspondence between the multicast address and the corresponding egress PE can be maintained in different manners. The following is an example of saving the corresponding relationship by using a multicast forwarding entry, and three types of maintaining the corresponding relationship. Ways to explain:

method one:

Each multicast address ( s, g ) corresponds to a multicast forwarding entry ((s, g), {PE}). At this time, any egress PE will not receive data that is not its own, but You need to maintain more multicast forwarding entries on the ingress PE.

Method 2:

Some multicast addresses with common characteristics share an aggregated multicast forwarding entry entry((*, g*), {PE}). When multiple multicast addresses share the same aggregated multicast forwarding entry, instead of maintaining an entry ((s, g), {PE}) for each (s, g), the aggregation technology is used. A plurality of different (s, g) identical features share an entry, thereby reducing the number of multicast forwarding items that the PE router needs to maintain, and reducing the burden on the router. The common features of the multiple multicast addresses may be: the prefixes of the g addresses are the same, the prefixes of the s addresses are the same, and of course, other common features may not be affected, and the implementation of the present invention is not affected.

In this case, in the foregoing step 202, the ingress PE is multicast according to the multicast data. Address (s, g), determining an aggregate multicast forwarding entry ((*, g*), {PE}) corresponding to the multicast address, and determining each PE in the forwarding item PE set {PE} as The egress PE that matches the multicast data; the egress PE of the multicast group corresponding to the multicast address (s, g) may be sent to the other multicast address (s, g,) the multicast data of the egress PE of the corresponding multicast group, wherein the (s, g,) and (s, g) have the same feature, sharing the same entry ((*, g*), {PE}), so the different egress PEs added to the groups (s, g) and (s, g,) can receive all the data about (*, g*), and the egress PE receives the multicast data according to The PIM forwarding table of the E-IP determines whether the received multicast data is redundant data, and if so, discards the multicast data.

Similarly, if the multicast forwarding entry is maintained in this manner, when the mapping between the multicast address and the corresponding egress PE is established and deleted, the ingress PE is based on the multicast in the join packet or the quit packet. The address (s, g) determines an aggregated multicast forwarding entry corresponding to the address, and completes the step of establishing and deleting the corresponding relationship in the aggregated multicast forwarding entry.

Method three:

In this mode, all multicast addresses share a multicast forwarding entry ((*, *), {PE}). At this time, the intermediate transport network using I-IP is equivalent to a local area network (LAN), and the ingress PE needs The multicast data is encapsulated and sent to all PEs in entry((*,*),{PE}) in unicast mode.

In this way, the ingress PE only needs to maintain an entry((*,*),{PE}) forwarding entry. The specific maintenance mode can be as follows: Use the Border Gateway Protocol (BGP) message instead of the join message to maintain the entry ((*,*),{PE}) entry, ie: The ingress PE will all known BGP neighbors. The PE is added to the {PE} set. After receiving the multicast data, the ingress PE sends the multicast data to all BGP neighbor PEs in unicast mode.

This method is suitable for the case where the number of PEs in the I-IP transmission network is not large, and the burden on the PE can be effectively alleviated.

Hereinafter, the device provided by the embodiment of the present invention will be described in detail.

Referring to FIG. 5, the apparatus for implementing multicast transmission provided in the embodiment of the present invention includes: a peripheral client network processing module 502, an intermediate transport network processing module 503, and an intermediate transport network transmission module 504, and the apparatus may further include: a peripheral client. The network transmission module 501 and the multicast forwarding correspondence storage module 505, wherein:

The multicast forwarding correspondence storage module 505 is configured to store a correspondence between the established multicast address and the egress PE; The peripheral client network transmission module 501 is configured to: receive the multicast data sent by the client network client, and send the multicast data to the peripheral client network processing module 502;

The peripheral client network processing module 502 is configured to: when determining that the received multicast data needs to be transmitted across the intermediate transmission network by querying the multicast routing table, sending the multicast data to the intermediate transmission network processing module 503;

The intermediate transmission network processing module 503 is configured to: determine, according to the multicast address of the multicast data, and the correspondence between the multicast address and the egress PE stored in the multicast forwarding correspondence storage module 505, Each of the egress data PEs that match the multicast data, and the multicast data are encapsulated by using the determined addresses of the egress PEs;

The intermediate transmission network transmission module 504 is configured to: send each multicast data encapsulated by the intermediate transmission network processing module 503 to the determined outlet PEs through the intermediate transmission network in a unicast manner.

In the preferred embodiment of the present invention, in order to enable the establishment and deletion of the correspondence in the multicast forwarding correspondence storage module 505, the apparatus further includes a multicast transition control module 506. At this time, the intermediate transmission network transmission module 504 is also used to:

Receiving a request to join or request to exit the packet transmitted through the intermediate transport network, and transmitting the message to the intermediate transport network processing module 503;

The intermediate transmission network processing module 503 is further configured to: decapsulate the encapsulated request or request to exit the packet, and send the decapsulated packet to the peripheral client network processing module 502 for processing; the peripheral client The network processing module 502 is further configured to: after receiving the request for decapsulation to join or request to quit the message, notify the multicast transition control module 506 to perform processing;

The multicast transition control module 506 is configured to: add or request to exit the multicast address carried in the packet according to the request, and update the correspondence between the multicast address stored in the multicast forwarding correspondence storage module 505 and the egress PE relationship.

In the above description, the apparatus for implementing multicast transmission corresponds to the ingress PE as described above, and when the apparatus is used as an egress PE, the intermediate transmission network processing module 503 may further be used to access the intermediate transmission network. The encapsulated multicast data received by the transmission module 504 is decapsulated, and the decapsulated multicast data is sent to the peripheral client network processing module 502;

The peripheral client network processing module 502 receives the received information through the peripheral client network transmission module 501. The decapsulated multicast data is further forwarded to complete the transmission of the multicast data in the peripheral client network.

Further, when the device that implements the multicast transmission is used as the egress PE, the peripheral client network processing module 502 is further configured to:

And determining, according to the unicast protocol forwarding table of the peripheral client network, whether the received decapsulated multicast data is redundant data, and if yes, discarding the multicast data.

The above is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

Claims

Rights request

A method for implementing multicast transmission, the method comprising:

2. The method according to claim 1, wherein the method further comprises:

The mapping between the multicast address and the corresponding egress PE is established on the ingress PE, and the specific processes include:

The client of the peripheral client network that requests to join the multicast group corresponding to the multicast address sends a request join message to the egress PE directly connected to the peripheral client network through the peripheral client network, where the request join message carries Have a multicast address;

After receiving the request to join the packet, the egress PE encapsulates the request join message and the address of the egress PE, and sends the request to the ingress PE through the intermediate transport network in a unicast manner;

The ingress PE receives the request join message sent by the egress PE, decapsulates the packet, and performs the following processing according to the multicast address in the egress packet:

If the correspondence between the multicast address of the request and the corresponding egress PE is already existing, the information about the egress PE obtained by the decapsulation is added to the corresponding relationship between the multicast address and the corresponding egress PE;

If the corresponding relationship between the multicast address of the request join message and the corresponding egress PE does not exist, the corresponding relationship is established on the ingress PE.

3. The method according to claim 1, wherein the method further comprises:

When the client of the peripheral client network requests to quit the multicast group corresponding to the multicast address, the corresponding relationship between the multicast address and the corresponding egress PE is deleted on the ingress PE, and the specific process includes:

The client of the peripheral client network requesting to leave the multicast group sends a request to exit the packet to the egress PE directly connected to the peripheral client network through the peripheral client network, where the request egress message carries a multicast address; The egress PE encapsulates the received request egress message with the address of the egress PE, and sends the request to the ingress PE through the intermediate transmission network in a unicast manner;

The ingress PE decapsulates the encapsulated request-received packet, and obtains the correspondence between the multicast address corresponding to the multicast address in the request and the egress PE, and obtains the corresponding relationship between the multicast address and the egress PE. The information of the egress PE is deleted in the correspondence.

The method according to any one of claims 1 to 3, wherein the correspondence between the multicast address and the corresponding egress PE is:

The correspondence between a multicast address and its corresponding egress PE.

Correspondence between the multicast address shared by at least two multicast addresses having a common feature and the corresponding egress PE.

The method according to claim 5, wherein the ingress PE sends the encapsulated multicast data to the determined egress PEs through the intermediate transport network in a unicast manner, and further includes:

After receiving the multicast data, the egress PE determines whether the multicast data is redundant data, and if yes, discards the multicast data.

Correspondence between the multicast address shared by all multicast addresses and the corresponding egress PE.

The method according to any one of claims 1 to 3, wherein the correspondence between the multicast address and the corresponding egress PE is saved by using a multicast forwarding entry.

The method according to any one of claims 1 to 3, wherein the encapsulated multicast data is sent to the determined outlets PE through the intermediate transmission network in a unicast manner. Also includes:

The egress PE decapsulates the encapsulated multicast data, and forwards the demodulated multicast data.

10. An apparatus for implementing multicast transmission, the apparatus comprising: a peripheral client network processing module, an intermediate transmission network processing module, and an intermediate transmission network transmission module, wherein: The peripheral client network processing module is configured to: when determining that the received multicast data needs to be transmitted across the intermediate transport network, send the multicast data to the intermediate transport network processing module;

The intermediate transmission network processing module is configured to: determine, according to the multicast address of the multicast data, and the correspondence between the established multicast address and the egress PE, each egress PE that matches the multicast data, and utilize the Determining, by the determined address of each of the egress PEs, the multicast data, and the intermediate transmission network transmission module is configured to: unicast each multicast data encapsulated by the intermediate transmission network processing module The respective outlet PEs are determined to be transmitted through the intermediate transmission network.

The device according to claim 10, further comprising: a peripheral client network transmission module, configured to: receive multicast data sent by the client network client, and send the multicast data to the peripheral client Network processing module;

The device according to claim 10 or 11, further comprising: a multicast forwarding correspondence storage module, configured to store a correspondence between the established multicast address and the egress PE.

The device according to claim 11, wherein the device further comprises a multicast transition control module, wherein the intermediate transport network transmission module is further configured to:

Receiving, by the intermediate transmission network, the encapsulated request to join or request to exit the message, and transmitting the message to the intermediate transmission network processing module;

The intermediate transmission network processing module is further configured to: perform a decapsulation of the encapsulated request request or request to exit the packet, and send the decapsulated packet to the peripheral client network processing module for processing;

The peripheral client network processing module is further configured to: after receiving the request for decapsulation to join or request to quit the message, notifying the multicast transition control module to perform processing;

The multicast transition control module is configured to: join or request to quit the multicast address carried in the packet according to the request, and update a correspondence between the multicast address stored in the multicast forwarding correspondence storage module and the egress PE.

The apparatus according to claim 13, wherein the intermediate transmission network processing module is further configured to decapsulate the encapsulated multicast data received from the intermediate transmission network transmission module, and decapsulate the packaged data. Multicast data is sent to the peripheral client network processing module;

The peripheral client network processing module is further configured to further forward the received decapsulated multicast data by using the peripheral client network transmission module.

15. The apparatus according to claim 14, wherein the peripheral client network processing module further Used for:

Determining whether the received decapsulated multicast data is redundant data, and if so, discarding the multicast data.