CN102355358B - Method and device for realizing multicast - Google Patents

Abstract

The invention discloses a method for realizing multicast. The method includes: when receiving an IGMP Report message, the user VLAN and the multicast group IP address carried in the IGMP Report message, as well as the message receiving port and the multicast The multicast VLAN bound to the IP address is bound and saved; when receiving the IGMP Leave message, it only needs to send the IGMP Query message to the corresponding VLAN on the specified port. Based on the same idea, the present invention also proposes a device, which improves the utilization rate of bandwidth on the user side and reduces bandwidth pressure on the network side under the condition of simple configuration.

Description

Method and device for implementing multicast

technical field

The invention relates to the technology in the communication field, in particular to a method and equipment for realizing multicast.

Background technique

Multicast can realize efficient point-to-multipoint network connection between multicast source and users: multicast source simultaneously transmits the same multicast data to multiple users belonging to the same multicast group. However, only one copy of such data is transmitted before the backbone network and through the access network replication point. After entering the access network, the multicast data is replicated at the replication point to become multiple copies of the same data and delivered to different receivers.

The realization of multicast depends on the interaction of multicast protocol packets (IGMP packets). By sending a multicast protocol report message (IGMP Report message), the user tells the switch that he wants to join and receive information from a specific multicast source, and the switch actively learns such a request and saves the corresponding relationship between the user and the multicast group; , the user informs the switch to leave a specific multicast group by sending a multicast protocol leave message (IGMP Leave message). In order not to affect the reception of multicast data by other users, the switch needs to send a multicast protocol query message (IGMP Query message) to the multicast group after receiving the multicast leave message to confirm whether There are other users. If not, the switch will no longer maintain the corresponding user/multicast group correspondence, and notify the router not to send the multicast data.

The realization of the existing multicast leave function is based on the port. When the switch receives the IGMPLeave message from a certain port, it directly deletes the corresponding relationship between the port and the multicast group from the multicast forwarding entry. When there is only one user on the port, such a processing strategy can naturally save bandwidth. However, if multiple VLANs are configured under the port, and there are several multicast users under each VLAN, the switch needs to check whether there are other multicast users under the port, which will inevitably cause user Wasted side bandwidth.

Referring to FIG. 1 , FIG. 1 is a schematic structural diagram for realizing multicast leaving based on ports. Among Fig. 1, switch 103 has configured a plurality of VLANs under port 1 (Port 1) to Port n of user side respectively, and there are several (greater than 1) multicast users under each VLAN. The switch 103 is connected to the server 103 through the router 102 . Assume that User 1 sends an IGMP Leave message to the switch. At this time, the switch only knows that the message has been received at its port 1, but it cannot be distinguished which VLAN the message comes from. In this case, the switch needs to send an IGMP Query message to all users contained in all VLANs on port 1 to determine whether there are other multicast users receiving the group information carried in the IGMP Leave message under this port. group service. If n VLANs are configured under port 1, and there are m users under each VLAN, then the number of IGMPQuery messages that the switch needs to send is (m X n). The maximum number of VLANs can usually be 4094. The number of users in the same VLAN is uncertain, so (m X n) may be a very large value, and users may frequently join and leave a certain multicast group, so a large number of IGMP Query packets greatly waste the precious bandwidth on the user side after the replication point, which violates the original design intention of the multicast protocol.

It can be seen from the above that the implementation of the existing multicast leave function causes a waste of user-side bandwidth.

Contents of the invention

In view of this, the present invention provides a method and device for implementing multicast, which improves the utilization rate of user-side bandwidth under the condition of simple configuration.

In order to solve the problems of the technologies described above, the technical solution of the present invention is achieved in the following way:

A method for realizing multicast, the method comprising: when receiving a multicast protocol report IGMP Report message sent by a user side, the message receiving port of the IGMP Report message, the carried user's virtual local area network VLAN and group The multicast group IP address and the multicast VLAN bound to the multicast group IP address are bound and saved;

When receiving the IGMP Leave message sent by the user side, if the message receiving port, the carried user VLAN and the multicast group IP address of the IGMP Leave message are found in the information saved in the binding, and the The multicast VLAN bound by the multicast group IP address generates an IGMP Query message and sends a request to leave the multicast group IP address to all users in the user VLAN range on the message receiving port of the IGMP Leave message. Multicast protocol query IGMP Query message.

Wherein, after the message receiving port of the IGMP Report message, the carried VLAN and the multicast group IP address, and the multicast VLAN bound with the multicast group IP address are bound and saved, the method further include:

Obtain the multicast data flow required by the user side from the network side, and copy and send the multicast data flow to the corresponding user on the user side according to the message receiving port and user VLAN stored in the binding.

The method further comprises:

If the user response of the sent IGMP Query message is received within the preset query timeout time and query timeout times, continue to send the multicast stream to the user VLAN range on the message receiving port saved by the binding, otherwise, Delete the message receiving port, user VLAN, multicast group IP address and multicast VLAN stored in the binding.

The method further includes: pre-establishing a multicast forwarding entry, and storing the message receiving port, user VLAN, multicast group IP address and multicast VLAN binding in the multicast forwarding entry.

The method for finding the message receiving port of the IGMP Leave message bound and saved, the carried user VLAN and the multicast group IP address, and the multicast VLAN bound with the multicast group IP address is:

According to the message receiving port of the IGMP Leave message, the carried user VLAN and multicast group IP address, and the multicast VLAN bound with the multicast group IP address, find out in the multicast forwarding table item Bind and save the corresponding message receiving port, user VLAN, multicast group IP address and multicast VLAN.

A device for implementing multicast, the device comprising: a first receiving unit, a storage unit, a second receiving unit, a processing unit, and a sending unit;

The first receiving unit is connected to the storage unit and is used to receive the multicast protocol report IGMP Report message sent by the user side;

The storage unit is connected to the processing unit, and is used for receiving the message receiving port of the IGMP Report message by the first receiving unit, the carried user virtual local area network VLAN and the multicast group IP address, and the address The bound multicast VLAN is bound and saved;

The second receiving unit is connected to the processing unit and is used to receive the IGMP Leave message from the multicast protocol sent by the user side;

The processing unit is connected to the sending unit, and is used to find the information of the IGMP Leave message in the information bound and saved by the storage unit according to the IGMP Leave message received by the second receiving unit When the message receiving port, the carried user VLAN and multicast group IP address, and the multicast VLAN bound with the multicast group IP address generate a multicast protocol query IGMP Query message;

The sending unit sends the IGMP Query message generated by the processing unit to all users in the user VLAN range on the message receiving port of the IGMPLeave message to send the multicast protocol query IGMP requesting to leave the multicast group IP address Query message.

Wherein, the first receiving unit is connected to the processing unit, and is further used to obtain the multicast data stream required by the user side from the network side;

The processing unit is further configured to copy the multicast data stream acquired by the first receiving unit according to the message receiving port and user VLAN stored in the binding;

The sending unit is further configured to send the multicast data stream copied by the processing unit to a corresponding user on the user side.

The processing unit is further configured to delete the message bound and saved by the storage unit if the second receiving unit does not receive the user response of the IGMP Query message within the preset query timeout time and the number of query timeout times Receive port, user VLAN, multicast group IP address and multicast VLAN;

The sending unit is used for the second receiving unit to continue sending messages to the user VLAN range on the message receiving port if the user response of the sent IGMP Query message is received within the preset query timeout time and query timeout times. Send the multicast stream within.

The storage unit is further used to establish a multicast forwarding entry, and store the message receiving port, user VLAN, multicast group IP address and multicast VLAN binding in the multicast forwarding entry.

The processing unit is configured to, according to the message receiving port of the IGMP Leave message, the carried user VLAN and the multicast group IP address, and the multicast VLAN bound with the multicast group IP address, in the storage The corresponding message receiving port, user VLAN, multicast group IP address and multicast VLAN stored in the binding are found in the multicast forwarding table item in the unit.

In summary, when the present invention receives the IGMP Report message, the user VLAN and the multicast group IP address carried by the IGMP Report message, as well as the message receiving port and the multicast VLAN bound with the multicast IP address Save the binding; when receiving the IGMP Leave message, only send the IGMP Query message to the corresponding VLAN on the specified port. In the case of simple configuration, the utilization rate of bandwidth on the user side is improved.

Description of drawings

Fig. 1 is a schematic structural diagram of implementing multicast departure based on ports;

Fig. 2 is a schematic flow diagram of a method for realizing multicast in the present invention;

Fig. 3 is a schematic flow diagram of a method for realizing multicast according to a specific embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a device for realizing multicast according to the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the solutions of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

The device for realizing the present invention only needs to have the multicast function, such as a switch, router, HUB, epon, etc. with the multicast function. In the specific description of the method embodiments below, a switch is taken as an example for convenience of description, and the switch has a multicast function.

Referring to FIG. 2 , FIG. 2 is a schematic flowchart of a method for implementing multicast in the present invention. The specific steps are:

Step 201, when the switch receives the IGMP Report message sent by the user side, the message receiving port of the IGMPReport message, the user's virtual local area network VLAN and the multicast group IP address carried, and the multicast group IP address are bound Bind and save the specified multicast VLAN.

After the relevant information is bound and saved in this step, obtain the multicast data flow required by the user side from the network side, and copy and send the obtained multicast data flow to the corresponding user side according to the saved message receiving port and user VLAN. user.

Step 202, when the switch receives the IGMP Leave message sent by the user side, if the message receiving port, the carried user VLAN and the multicast group IP address of the IGMP Leave message are found in the information saved in the binding, And the multicast VLAN bound with the multicast group IP address, then generate an IGMPQuery message and send the requested IGMP request to leave the multicast group IP address to all users in the user VLAN range on the message receiving port of the IGMP Leave message. Query message.

After sending the IGMP Query message to the user side in this step, if the user response of the sent IGMP Query message is received within the preset query timeout time and query timeout times, then continue to send the message to the user VLAN on the message receiving port. Send the multicast stream within the range, otherwise, delete the corresponding message receiving port, user VLAN, multicast group IP address and multicast VLAN stored in the binding.

The whole process of implementing multicast will be described in detail below through specific embodiments with reference to the accompanying drawings.

Referring to FIG. 3 , FIG. 3 is a schematic flowchart of a method for implementing multicast according to a specific embodiment of the present invention. The specific steps are:

Step 301, start.

In step 302, the switch configures the binding relationship between the multicast group IP address and the multicast VLAN.

Most of the current multicast services are paid services, and the user's access authority must be controlled. Before obtaining the authority, the user cannot access a specific multicast service. This limitation can be further extended to different multicast service providers, and the multicast services provided by different providers are bound to different multicast VLANs. Different multicast services correspond to different multicast IP addresses, thereby isolating different groups. broadcast source, improving the manageability and operability of multicast services.

In step 303, the switch configures multicast-related attributes.

The realization of the multicast function also depends on some auxiliary functions, such as the aging time of multicast forwarding entries, query timeout time, query timeout times, etc. These parameters can all be preset according to actual applications.

Step 304, enabling the multicast function.

The switch enables the multicast function, and the multicast task or process will monitor the multicast protocol packets.

Steps 302 to 304 are the same as those in the prior art, and will not be repeated here.

Step 305, receiving the multicast protocol message.

The switch receives the multicast protocol packet and analyzes it.

Step 306, judging whether the received multicast protocol message is an IGMP Report message, if yes, then execute step 307; otherwise, execute step 310.

In step 307, the switch establishes a multicast forwarding entry.

For the entries established in this step, refer to Table 1, and Table 1 is the multicast forwarding entries of the present invention.

Message receiving port User VLAN Multicast group ip address Multicast VLAN other

Table 1

In table 1, the message receiving port is the port number receiving the IGMP Report message; the user VLAN is the VLAN number carried by the IGMP Report message; the multicast group ip address is the multicast group ip address configured in step 302; the multicast VLAN It is the multicast VLAN number configured in step 302; others are used by users to save other information according to actual needs.

Take Figure 1 as an example, assuming that user 1 requests the multicast data flow of the multicast group IP address 239.1.1.2 from the switch, and sends an IGMP Report message to the switch. The user VLAN where user 1 is located is VLAN 1, the receiving port of the Report message is port 1, and the data flow of the multicast group 239.1.1.2 is configured in VLAN 200, so the IGMP Report message sent by user 1 to the switch carries the user VLAN as VLAN1, the multicast group IP address is 239.1.1.2, enter the switch through port 1 of the switch, and find the bound multicast VLAN200 on the switch through the multicast group IP address.

The switch receives the IGMP Report message sent by user 1, parses the message, and converts the user VLAN and multicast group ip address carried in the IGMP Report message, as well as the message receiving port and the multicast IP address obtained on the switch The bound multicast VLAN binding is stored in the multicast group forwarding table. Referring to Table 2, Table 2 is the multicast forwarding entry of the specific embodiment of the present invention.

Table 2

If users of other VLANs send IGMP Report messages, the switch will also store the above information carried in the IGMP Report messages in the multicast group forwarding table established by the switch. For different multicast VLANs or user ports, etc., the switch maintains one multicast forwarding table item uniformly, or maintains different multicast forwarding tables separately, according to the convenience of the user.

After the multicast forwarding entry is established, a timer is set for the multicast entry to record the aging time of the corresponding multicast forwarding entry. During the aging time, if an IGMP Report message from the user side is received, and the message receiving port of the IGMP Report message, the carried user VLAN and multicast group IP address, and the binding with the multicast IP address If the multicast VLAN has been bound and stored in the multicast forwarding entry, update the aging time of the corresponding multicast forwarding entry; otherwise, delete the corresponding multicast forwarding entry.

Step 308, the switch requests the multicast data flow from the network side.

After binding and storing the corresponding information in the multicast forwarding table entry, the switch sends an IGMPReport message to the network side to request the multicast data flow required by its users. When multiple users apply for the same multicast group, the switch can also enable the proxy function to combine multiple Report messages.

Step 309, receiving the multicast data flow from the network side, copying the multicast data flow according to the multicast forwarding entry and sending it to the corresponding user. Execute step 314 .

The basis of multicast data stream duplication is the message receiving port and user VLAN bound and saved in the multicast forwarding entry. Taking Figure 1 as an example, the multicast data stream requested by user 1 is copied and sent to each user under VLAN1 on port1.

Step 310, the switch judges whether the received multicast protocol message is an IGMP leave message, if yes, executes step 311; otherwise, executes step 314.

Step 311, if the switch finds the corresponding multicast forwarding entry, it generates and sends an IGMPQuery message according to the message receiving port, the user VLAN and the multicast group IP address that the IGMP Leave message requests to leave.

When the switch receives the IGMP Leave message, it will perform multicast forwarding according to the receiving port of the message and the user VLAN and multicast group IP address carried in the IGMP Leave message, as well as the multicast VLAN bound to the multicast group IP address. If it is found that the multicast forwarding table entry corresponding to the above binding storage information exists, an IGMP Query message will be generated and sent to all users within the corresponding user VLAN range on the message receiving port of the IGMP Leave message. The user sends an IGMP Query message requesting to leave the IP address of the multicast group; for example, the receiving port of the Report message in the multicast forwarding entry is port1, and the corresponding user VLAN is VLAN1, then the IGMP Query message is sent on port1 sent within the range of VLAN1.

Step 312, whether a user response to the sent IGMPQuery message is received within the preset query timeout time and query timeout times, if yes, go to step 305; otherwise, go to step 313.

According to whether there is a user responding to the query in the user VLAN range corresponding to the Report message receiving port in the multicast forwarding entry, it is determined whether there is still a user of the multicast group in the range.

Step 313, the switch deletes the multicast forwarding entry corresponding to the multicast.

Within the preset query timeout time and the number of query timeouts, if the switch does not receive a query message from a user in the corresponding user VLAN on the receiving port of the Report message in the multicast forwarding table entry, the corresponding multicast forwarding table will be deleted. item. And notify the network side that the user VLAN corresponding to the port in the multicast forwarding entry and the corresponding multicast are no longer processed. For example, if the receiving port of the Report message in the multicast forwarding entry is port1, the corresponding user VLAN is VLAN1, and the multicast group ip address is 239.1.1.2, then the network side is notified not to process the multicast of VLAN1 on port1 as 239.1. 1.2 message.

Step 314, end.

Based on the same inventive idea, the present invention also proposes a device for realizing multicast. The device has multicast function. Referring to FIG. 4, FIG. 4 is a schematic structural diagram of a device for realizing multicast according to the present invention. The device includes: a first receiving unit 401 , a storage unit 402 , a second receiving unit 403 , a processing unit 404 and a sending unit 405 .

The first receiving unit 401 is connected to the storage unit 402 and configured to receive the IGMPReport message sent from the user side.

The storage unit 402 is connected with the processing unit 404, and is used for receiving the message receiving port of the IGMPReport message by the first receiving unit 401, the carried user virtual local area network VLAN and the multicast group IP address, and the group bound to the address Broadcast VLAN for binding and saving.

The second receiving unit 403 is connected with the processing unit 404, and is used for receiving the multicast protocol IGMP Leave message sent from the user side.

The processing unit 404 is connected to the sending unit 405, and is used to find the message receiving port of the IGMPLeave message and the carried message in the information stored in the storage unit 402 according to the IGMP Leave message received by the second receiving unit 403. When the user VLAN, multicast group IP address, and the multicast VLAN bound to the multicast group IP address are generated, a multicast protocol query IGMP Query message is generated.

Sending unit 405 sends the IGMP Query message that the request leaves the multicast group IP address to all users in the user VLAN range on the message receiving port of the IGMP Leave message by the IGMP Query message generated by the processing unit 404.

Preferably,

The first receiving unit 401 is connected to the processing unit 404, and is further configured to obtain the multicast data stream required by the user side from the network side.

The processing unit 404 is further configured to copy the multicast data flow acquired by the first receiving unit 401 according to the saved message receiving port and user VLAN.

The sending unit 405 is further configured to send the multicast data stream copied by the processing unit 404 to a corresponding user on the user side.

Preferably,

The processing unit 404 is further used for the second receiving unit 403 to delete the corresponding message receiving port, the corresponding message receiving port, and User VLAN, multicast group IP address and multicast VLAN.

The sending unit 405 is used for the second receiving unit 403 to continue to send the IGMP Query message to the user VLAN range on the message receiving port if the second receiving unit 403 receives the user response of the sent IGMP Query message within the preset query timeout time and query timeout times. The multicast stream.

Preferably,

The storage unit 402 is further configured to establish a multicast forwarding entry, and store the message receiving port, user VLAN, multicast group IP address and multicast VLAN binding in the multicast forwarding entry.

Preferably,

Processing unit 404, for according to the message receiving port of IGMP Leave message, carried user VLAN and multicast group IP address, and the multicast VLAN bound with this multicast group IP address, the group in storage unit 402 Find the corresponding message receiving port, user VLAN, multicast group IP address and multicast VLAN saved in the broadcast forwarding table entry.

To sum up, when the device with multicast function receives the IGMP Report message, the present invention does not need additional manual configuration, and the message receiving port, user VLAN, multicast group IP address and the multicast address bound to the address VLANs are stored in multicast forwarding entries. When the device obtains the multicast data stream requested by the user side, it copies it according to the multicast forwarding table entry and sends it to the corresponding user on the user side. Therefore, the multicast data replication point is lowered from the router to the device, reducing the burden on the access network. When the device receives the IGMPleave message, it sends the IGMP Query message according to the multicast forwarding table item, distinguishes users with a smaller granularity, reduces the sending range of the IGMP Query message, and improves the bandwidth of the user side under the condition of simple configuration utilization rate.

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

Claims (10)

1. A method for realizing multicast, the method is applied in a network system including equipment with multicast function, the equipment configures a plurality of virtual local area network VLANs under each port on the user side, and each VLAN has more than one group Broadcasting user, it is characterized in that, described method comprises: When receiving the multicast protocol report IGMP Report message sent by the user side, the message receiving port of the IGMPReport message, the carried user's virtual local area network VLAN and the multicast group IP address, and the multicast group IP address The bound multicast VLAN is bound and saved; When receiving the multicast leaving IGMP Leave message sent by the user side, if the message receiving port, the carried user VLAN and the multicast group IP address of the IGMP Leave message are found in the information saved in the binding , and the multicast VLAN bound with the multicast group IP address, an IGMPQuery message is generated and all users within the user VLAN range on the message receiving port of the IGMP Leave message send the request to leave the multicast group IP The multicast protocol of the address queries the IGMP Query message. 2. The method according to claim 1, characterized in that, the message receiving port of the IGMP Report message, the carried VLAN and the multicast group IP address, and the group bound with the multicast group IP address After the broadcast VLAN is bound and saved, the method further includes: Obtain the multicast data flow required by the user side from the network side, and copy and send the multicast data flow to the corresponding user on the user side according to the message receiving port and user VLAN stored in the binding. 3. The method according to claim 1 or 2, wherein, after sending the IGMPQuery message to the user side, the method further comprises: If the user response of the sent IGMP Query message is received within the preset query timeout time and query timeout times, continue to send the multicast stream to the user VLAN range on the message receiving port saved by the binding, otherwise, Delete the message receiving port, user VLAN, multicast group IP address and multicast VLAN stored in the binding. 4. The method according to claim 3, characterized in that, the method further comprises: setting up a multicast forwarding table item in advance, adding the message receiving port, user VLAN, multicast group IP address and multicast VLAN The binding is stored in the multicast forwarding entry. 5. method according to claim 4, it is characterized in that, the message receiving port of described IGMP Leave message that described binding preservation is found, the user VLAN that carries and multicast group IP address, and with this group The method of broadcasting the multicast VLAN bound with the group IP address is as follows: According to the message receiving port of the IGMP Leave message, the carried user VLAN and multicast group IP address, and the multicast VLAN bound with the multicast group IP address, find out in the multicast forwarding table item Bind and save the corresponding message receiving port, user VLAN, multicast group IP address and multicast VLAN. 6. A kind of equipment that multicast realizes, and this equipment configures a plurality of virtual local area network VLANs under each port of user side, and there is more than one multicast user under each VLAN, it is characterized in that, described equipment comprises: the first receiving unit , a storage unit, a second receiving unit, a processing unit and a sending unit; The first receiving unit is connected to the storage unit and is used to receive the multicast protocol report IGMP Report message sent by the user side; The storage unit is connected to the processing unit, and is used for receiving the message receiving port of the IGMP Report message by the first receiving unit, the carried user virtual local area network VLAN and the multicast group IP address, and the address The bound multicast VLAN is bound and saved; The second receiving unit is connected to the processing unit and is used to receive the IGMP Leave message from the multicast protocol sent by the user side; The processing unit is connected to the sending unit, and is used to find the information of the IGMP Leave message in the information bound and saved by the storage unit according to the IGMP Leave message received by the second receiving unit When the message receiving port, the carried user VLAN and multicast group IP address, and the multicast VLAN bound with the multicast group IP address generate a multicast protocol query IGMP Query message; The sending unit sends the IGMP Query message generated by the processing unit to all users in the user VLAN range on the message receiving port of the IGMPLeave message to send the multicast protocol query IGMP requesting to leave the multicast group IP address Query message. 7. The apparatus of claim 6, wherein The first receiving unit is connected to the processing unit, and is further used to obtain the multicast data stream required by the user side from the network side; The processing unit is further configured to copy the multicast data stream acquired by the first receiving unit according to the message receiving port and user VLAN stored in the binding; The sending unit is further configured to send the multicast data stream copied by the processing unit to a corresponding user on the user side. 8. Apparatus according to claim 6 or 7, characterized in that The processing unit is further configured to delete the message receiving port bound and saved by the storage unit if the second receiving unit does not receive the user response of the IGMP Query message within the preset query timeout time and query timeout times , user VLAN, multicast group IP address and multicast VLAN; The sending unit is used for the second receiving unit to continue sending messages to the user VLAN range on the message receiving port if the user response of the sent IGMP Query message is received within the preset query timeout time and query timeout times. Send the multicast stream within. 9. The apparatus of claim 8, wherein The storage unit is further used to establish a multicast forwarding table item, and store the message receiving port, user VLAN, multicast group IP address and multicast VLAN binding in the multicast forwarding table item. 10. The apparatus of claim 9, wherein: The processing unit is configured to, according to the message receiving port of the IGMP Leave message, the carried user VLAN and the multicast group IP address, and the multicast VLAN bound with the multicast group IP address, in the storage The corresponding message receiving port, user VLAN, multicast group IP address and multicast VLAN stored in the binding are found in the multicast forwarding table item in the unit.

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