Method and equipment for shortening congestion of practical general multicast network

Abstract

The invention provides a method and equipment for shortening congestion of a practical general multicast network. The method comprises the following steps: each switching device sends a flow first segment message counting notification message and a flow tail segment message counting notification message to a convergent point in a PGM network; wherein the flow head segment message counting notification message and the flow tail segment message counting notification message respectively carry a count value of a first part of original data messages and a count value of a second part of original data messages of each service flow of the specified multicast group; the rendezvous point calculates the end-to-end packet loss rate in the PGM network based on the flow first segment message counting notification message or the flow tail segment message counting notification message of each switching device; the convergent point sends a flow control notification message with the highest end-to-end packet loss rate to a multicast source; and the multicast source reduces the sending rate of the specified multicast group based on the flow control notification message.

Description

Technical Field

[0001] The present disclosure relates to communication technology, and more particularly to a method and device for shortening congestion in a practical general multicast network. Background Art

[0002] PGM (Pragmatic General Multicast) is a reliable multicast transmission protocol suitable for multicast data that needs to be ordered or unordered and non-repeated from multiple multicast sources (senders) to multiple receivers (receivers).

[0003] The multicast source sends ODATA (Original Data) messages in order according to the local policy custom sending window. The multicast receiver compares the sequence number of the currently received ODATA with the sequence number of the previously received ODATA. If there is a gap in the sequence number, it is considered that packet loss has occurred. It waits for a random time to confirm that no matching NAK (matching NAK) or matching (matching NCF) is received, and then sends a unicast NAK (Non-Acknowledgment) message on the reverse path of the distribution tree (Distribution Tree) from the multicast source.

[0004] The multicast receiver calculates the packet loss rate of the multicast group to which ODATA belongs, and can send the calculated packet loss rate to the multicast source through a negative acknowledgment message; the three-layer switching device receives the negative acknowledgment message and writes the local link packet loss rate, and sends it back to the multicast source. The multicast source receives the NAK message and reduces the sending rate of the original data message based on the highest packet loss rate. Since the flow control mechanism is initiated by the negative acknowledgment message sent by the multicast receiver, after the multicast source receives the flow control request, congestion in the PGM has occurred for a period of time. The multicast source still sends the original data message at the original sending rate. Not only is the congestion likely to continue, but the sequence number of the lost multicast data message in the NAK message is not within the current sending window. The multicast source no longer sends the repair message (Repair packet) of the original data message; the receiver cannot repair the multicast message. Summary of the invention

[0005] The purpose of the present disclosure is to provide a method and device for shortening the congestion of a practical general multicast network, thereby preventing a receiver from being unable to repair a multicast message.

[0006] To achieve the above-mentioned purpose, the present disclosure provides a method for shortening the congestion of a practical general multicast network, the method comprising each switching device sending a stream head segment message count notification message and a stream tail segment message count notification message to a convergence point in a PGM network; wherein the stream head segment message count notification message and the stream tail segment message count notification message respectively carry the count value of the first part of the original data message and the count value of the second part of the original data message of each service flow of the specified multicast group; the convergence point calculates the end-to-end packet loss rate in the PGM network based on the stream head segment message count notification message or the stream tail segment message count notification message of each switching device; the convergence point sends a flow control notification message of the highest end-to-end packet loss rate to the multicast source; the multicast source reduces the sending rate of the specified multicast group based on the flow control notification message.

[0007] To achieve the above-mentioned purpose, the present disclosure provides a device for shortening the congestion of a practical general multicast network, the device comprising a processor, a machine-readable storage medium, a memory, a switching chip, and a network interface; the processor performs the following operations by running the machine-executable instructions recorded in the machine-readable storage medium, receiving a stream head segment message count notification message and a stream tail segment message count notification message from each switching device in the PGM network; wherein the stream head segment message count notification message and the stream tail segment message count notification message respectively carry the count value of the first part of the original data message and the count value of the second part of the original data message of each service flow of the specified multicast group; based on the stream head segment message count notification message or the stream tail segment message count notification message from each switching device, the end-to-end packet loss rate in the PGM network is calculated; and the flow control notification message with the highest end-to-end packet loss rate is sent to the multicast source.

[0008] To achieve the above-mentioned purpose, the present disclosure also provides a device for shortening the congestion of a practical general multicast network, the device including a processor, a machine-readable storage medium, a memory, a switching chip, and a network interface; the processor performs the following operations by running the machine-executable instructions recorded in the machine-readable storage medium to establish a pair of first-segment statistical flow table entries and a tail-segment statistical flow table for a specified multicast group; based on the first-segment statistical flow table entries, the number of messages of the first part of the original data messages of the service flow of the specified multicast group is counted; based on the tail-segment statistical flow table entries, the number of messages of the second part of the original data messages of the service flow of the specified multicast group is counted.

[0009] The beneficial effect of the present invention is that the aggregation point notifies the multicast source of the packet loss rate of the designated multicast group of the PGM network, and the multicast source promptly reduces the sending rate of the original data message of the designated multicast group, which not only quickly shortens the congestion in the PGM network, but also avoids the sending window of the original data message from sliding to the next sending window. In this way, a repair message can be sent to the multicast receiver according to the sequence number of the lost multicast data message of the NAK message of the multicast receiver. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A schematic diagram of an embodiment of a method for shortening congestion in a practical general multicast network provided by the present disclosure;

[0011] Figure 2 A schematic diagram of a practical universal multicast network provided by an embodiment of the present disclosure;

[0012] Figure 3 A schematic diagram of shortening the congestion of a practical general multicast network provided by the present disclosure;

[0013] Figure 4A-4B A schematic diagram of shortening the congestion of a practical universal multicast network provided by another embodiment of the present disclosure;

[0014] Figure 5 A schematic diagram of an embodiment of a device for shortening congestion in a practical universal multicast network provided by an embodiment of the present disclosure;

[0015] Figure 6 A schematic diagram of an embodiment of a device for reducing congestion in a practical universal multicast network provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0016] The present invention will be described in detail with multiple examples shown in multiple figures. In the following detailed description, multiple specific details are used to provide a comprehensive understanding of the present disclosure. Known methods, steps, components and circuits are not described in detail in the examples to avoid making these examples difficult to understand.

[0017] Among the terms used, the term "include" means including but not limited to; the term "contain" means including but not limited to; the terms "above", "within" and "below" are inclusive of the number; the terms "greater than" and "less than" are exclusive of the number. The term "based on" means based on at least a part thereof.

[0018] Figure 1 The present disclosure provides a method embodiment for shortening the congestion of a practical general multicast network, comprising the following steps:

[0019] Step 101, each switching device sends a flow head segment message count notification message and a flow tail segment message count notification message to a convergence point in the PGM network;

[0020] The flow first segment message count notification message and the flow tail segment message count notification message carry the count value of the first part of the original data message and the count value of the second part of the original data message of each service flow of the specified multicast group respectively;

[0021] Step 102, the convergence point calculates the end-to-end packet loss rate in the PGM network based on the flow head segment message count notification message or the flow tail segment message count notification message of each switching device;

[0022] Step 103, the convergence point sends a flow control notification message of the highest end-to-end packet loss rate to the multicast source;

[0023] Step 104: The multicast source reduces the sending rate of the designated multicast group based on the flow control notification message.

[0024] The beneficial effect of the present invention is that the aggregation point notifies the multicast source of the packet loss rate of the designated multicast group of the PGM network, and the multicast source promptly reduces the sending rate of the original data message of the designated multicast group, which not only quickly shortens the congestion in the PGM network, but also avoids the sending window of the original data message from sliding to the next sending window. In this way, a repair message can be sent to the multicast receiver according to the sequence number of the lost multicast data message of the NAK message of the multicast receiver.

[0025] Figure 2 A schematic diagram of a practical universal multicast network provided by an embodiment of the present disclosure. Switch A is configured as a Rendezvous Point (RP) or, via switches A-Switch I, switches A are elected as RP according to PIM-SM (Protocol Independent Multicast-Sparse Mode).

[0026] The multicast source s1 customizes the sending window according to the local policy and sends the ODATA data packets of the multicast group in sequence.

[0027] The protocol number of the PGM protocol is 113. Different types of messages of the PGM protocol are used to implement different functions. In the PGM protocol, the type field value of the data packet is 4.

[0028] Therefore, switch A to switch F first identify the PGM protocol message according to the protocol number; then, based on the message type of the PGM protocol message being a data message represented by type 4, they identify that an ODATA message has been received, rather than other types of control messages or confirmation messages.

[0029] Figure 2 In the example, the receivers R1 and R2 can initiate active pruning messages (prune) according to the PIM-SM protocol. The messages from the multicast source S1 are sent to the multicast receivers R1 and R2 on the multicast tree via switch B, switch A, switch C, switch D, and switch E.

[0030] Switch B-Switch E establishes a pair of first-segment statistics flow table entries and tail-segment statistics flow table for the multicast group according to the received ODATA first message; in the first-segment statistics flow table entry, the source IP address is the IP address of the multicast source s1, the destination IP address is the multicast group IP address, and the identification value of the IP header is 0-32767; the action item is the message quantity count; in the tail-segment statistics flow table entry, the source IP address is the IP address of the multicast source s1, the destination IP address is the multicast group IP address, and the identification value of the IP header is 32768-65535; the action item is the message quantity count;

[0031] In switch B-switch E, the first segment statistical flow entry is used to record the number of the first part of the original data packets with identification values ​​of 0-32767 in each service flow of the multicast group, and the tail segment statistical flow entry records the number of the original data packets with identification values ​​of 32768-65535 in each service flow.

[0032] The original data packets received by switch B and switch E are matched to the first segment statistics flow entry according to the source IP address, destination IP address, and identification value of the IP header, and the number of packets with service flow identification values ​​of 0-32767 is refreshed.

[0033] The original data packets received by switch B-switch E are matched to the tail segment statistics flow table entry according to the source IP address, destination IP address and identification value of the IP header, and a first segment message counting notification message is generated. The number of messages recorded in the first segment statistics flow table entry is sent to the aggregation point switch A; then the number of messages with service flow identification values ​​of 32767-65535 is counted.

[0034] The original data message received by switch B-switch E is matched to the first segment statistics flow entry according to the source IP address, destination IP address and identification value Identification0 in the IP header, and a tail segment message count notification message is generated.

[0035] After the multicast source sends 65536 original data packets of a service flow of the multicast group, the IP identification value of the original data packet of the next hop service flow sent out is flipped to 0. Therefore, switch B-switch I recounts the next original data packet.

[0036] In the present disclosure, each switching device counts the number of the first part of the original data message of each service flow based on the flow head section statistics flow table entry, and divides each service flow of the multicast group into two parts and counts them separately, so as to prevent the switch from being unable to distinguish the disordered original data message and the original data message with the flipped identification value. For example, the identification values ​​of the two original data messages received by the switch are both 1, and the original data message received after the first section statistics flow table entry matching is completed is out of order; the original data message manually pressed after the tail section statistics flow table entry matching is completed is the original data message of the next service flow, and the first section statistics flow table entry matching should be performed.

[0037] Figure 3 A schematic diagram of shortening the congestion of a practical universal multicast network provided by the present disclosure;

[0038] Switch B, switch C (not shown in the figure), switch D (not shown in the figure), and switch E respectively send flow header message count notification messages 301 to switch A serving as the RP.

[0039] Switch A identifies the sending switch based on the source IP address of each flow header message count announcement message 301, and calculates the number of messages received by switch B, switch C, switch D, and switch E according to the number of messages written to each flow header message count announcement message 301, and calculates the end-to-end packet loss rate between the two switches on the multicast tree according to the packet loss rate of each switch.

[0040] Figure 3 In the figure, switch A identifies the maximum end-to-end packet loss rate in the calculated end-to-end packet loss rate; sends it to the multicast source S1 through the flow control notification message 302; the source IP address is the IP address of switch A, and the destination IP address is the IP address of the multicast source s1; the type field is the custom specified value 0X20.

[0041] The multicast source S1 receives the flow control notification message 302, reads the maximum end-to-end packet loss rate, and reduces the sending rate of the original data messages of the multicast group.

[0042] It can be seen that in the present disclosure, the three-layer switching device of the PGM network is used to speed up the feedback of the packet loss rate and shorten the congestion time in the PGM network.

[0043] Switch B, switch C (not shown in the figure), switch D (not shown in the figure), and switch E respectively send flow tail segment message count notification messages 303 to switch A serving as the RP.

[0044] Switch A identifies the sending switch based on the source IP address of each flow tail segment message count announcement message 303, and calculates the number of messages received by switch B, switch C, switch D, and switch E according to the number of messages written in each flow tail segment message count announcement message 303, and calculates the end-to-end packet loss rate between the two switches on the multicast tree according to the packet loss rate of each switch.

[0045] Figure 3 In the calculation of the end-to-end packet loss rate, switch A identifies the maximum end-to-end packet loss rate; sends the flow control notification message 304 to the multicast source S1; the source IP address is the IP address of switch A, the destination IP address is the IP address of the multicast source S1; the type field is 0X20.

[0046] If the congestion of the PGM network has been improved after the previous flow control processing, the multicast source S1 receives the flow control notification message 304 and determines that the maximum end-to-end packet loss rate has decreased, then the multicast source S1 increases the sending rate of the original data messages of the multicast group.

[0047] If the previous flow control processing is not enough to improve the congestion of the PGM network, the multicast source S1 receives the flow control notification message 304 and determines that the maximum end-to-end packet loss rate continues to increase. The multicast source S1 further reduces the sending rate of the original data messages of the multicast group to accelerate the shortening of the congestion time in the PGM network.

[0048] Figure 4A-4B A schematic diagram of shortening a practical universal multicast network congestion provided by another embodiment of the present disclosure.

[0049] Figure 4A In the figure, the multicast receiver R1 sends a NAK message 401 with a packet loss rate in the multicast tree; the switch D directly connected to the multicast receiver R1 receives the NAK message 401 and sends it in the multicast tree to the switch C (not shown); and the switch C finally sends it to the switch A.

[0050] Switch A receives NAK message 401 , removes the packet loss rate of multicast receiver R1 carried in NAK message 401 , and continues to send NAK message 401 to multicast source S1 according to the destination IP address of NAK message 401 .

[0051] The multicast source S1 receives the NAK message 401. If it is determined that the sequence number of the lost multicast data message in the NAK message 401 is within the current sending window, the multicast source S1 sends a repair message 403 to the multicast receiver R1.

[0052] Figure 4AIn the figure, the multicast receiver R2 sends a NAK message 402 with a packet loss rate in the multicast tree; the switch E directly connected to the multicast receiver R2 receives the NAK message 401 and sends it in the multicast tree to the switch C (not shown); and the switch C finally sends it to the switch A.

[0053] Switch A receives NAK message 402 , removes the packet loss rate of multicast receiver R1 carried in NAK message 402 , and continues to send NAK message 402 to multicast source S1 according to the destination IP address of NAK message 402 .

[0054] The multicast source S1 receives the NAK message 402. If it is determined that the sequence number of the lost multicast data message in the NAK message 402 is within the current sending window, the multicast source S1 sends a repair message 404 to the multicast receiver R2.

[0055] Figure 4B Before switch A sends NAK message 401 stripped of packet loss rate to multicast source S1, switch A identifies the sender as multicast receiver R1 according to the source IP address of NAK message 401, and identifies the directly connected switch of multicast receiver R1 on the multicast tree as switch D.

[0056] Switch A calculates the packet loss rate of the directly connected switch D based on the count value of the flow head segment message count notification message 301 and the count value of the flow tail segment message count notification message 303 sent by the directly connected switch A of the multicast receiver R1.

[0057] Switch A compares the packet loss rate of switch D with the packet loss rate in NAK message 401 and determines that they are the same, indicating that multicast receiver R1 does not send any further packets. Figure 4A As shown in the figure, a NAK message is sent with the packet loss rate stripped off.

[0058] Figure 4B Before switch A sends NAK message 402 stripped of packet loss rate to multicast source S1, switch A identifies the sender as multicast receiver R2 according to the source IP address of NAK message 402, and identifies the directly connected switch of multicast receiver R2 on the multicast tree as switch E.

[0059] Switch A calculates the packet loss rate of the directly connected switch E based on the count value of the flow head segment message count notification message 301 and the count value of the flow tail segment message count notification message 303 sent by the directly connected switch E of the multicast receiver R2.

[0060] Switch A compares the packet loss rate of switch D with the packet loss rate in NAK message 401 and determines that they are the same, indicating that multicast receiver R2 further sends packets and then follows Figure 4AAs shown, a NAK message 402 stripped of the packet loss rate is sent. Afterwards, switch A generates a flow control notification message 501; the flow control notification message 501 carries the packet loss rate of the multicast receiver R2.

[0061] The multicast source S1 receives the flow control notification message 501 and further reduces the sending rate of the original data messages of the multicast group.

[0062] Since the speed at which the multicast receivers feedback the packet loss rate is slower than the speed at which the switches on the multicast tree feedback the packet loss rate, the only switch as the RP notifies the multicast source of the packet loss rate of the PGM network in a timely manner, thus reducing the congestion of the PGM network. The original multicast data packets are finally forwarded to the multicast receivers through the network. The packet loss rate fed back by the multicast receivers is relatively more accurate. The multicast source continues to adjust the sending rate of the original multicast data packets according to the packet loss rate fed back by the multicast receivers, thus minimizing the number of packet losses.

[0063] Figure 5 Schematic diagram of a device embodiment for reducing congestion in a practical general multicast network provided by an embodiment of the present disclosure; the device 50 can be applied as a switching device as a convergence point in a PGM network. The device 50 includes a processor 51, a machine-readable storage medium 52, a switching chip 53, and a network interface 54.

[0064] The processor 51 performs the following operations by running the machine executable instructions recorded in the machine-readable storage medium 52, receiving a stream head segment message count notification message and a stream tail segment message count notification message from each switching device in the PGM network; wherein the stream head segment message count notification message and the stream tail segment message count notification message respectively carry the count value of the first part of the original data message and the count value of the second part of the original data message of each service flow of the specified multicast group; based on the stream head segment message count notification message or the stream tail segment message count notification message from each switching device, calculate the end-to-end packet loss rate in the PGM network; and send a flow control notification message with the highest end-to-end packet loss rate to the multicast source.

[0065] The processor 51 executes the machine executable instructions of the machine readable storage medium 52, and before executing the operation of sending the flow control notification message with the highest end-to-end packet loss rate to the multicast source, it also performs the following operations: receiving a negative acknowledgment message; stripping off the packet loss rate of the negative acknowledgment message; and sending a negative acknowledgment message with the packet loss rate stripped off to the multicast source.

[0066] The processor 51 executes the machine executable instructions recorded in the machine readable storage medium 52, and before executing the packet loss rate of stripping the negative acknowledgment message, it also performs the following operations: identifying the multicast receiver that sends the NAK message; identifying the direct switching device of the multicast receiver; calculating the packet loss rate of the direct switching device based on the count value of the first part of the original data message and the count value of the second part of the original data message announced by the direct switching device; determining that the packet loss rate of the direct switching device is less than the packet loss rate carried by the negative acknowledgment message, and identifying that the packet loss rate carried by the negative acknowledgment message is the highest end-to-end packet loss rate.

[0067] The processor 51 also performs the following operations by running the machine executable instructions recorded in the machine readable storage medium 52: identifying the multicast receiver that sends the NAK message; identifying the direct switching device of the multicast receiver; calculating the packet loss rate of the direct switching device based on the count value of the first part of the original data message and the count value of the second part of the original data message announced by the direct switching device; determining that the packet loss rate of the direct switching device is equal to the packet loss rate carried by the negative acknowledgement message, and identifying the highest end-to-end packet loss rate when calculating the end-to-end packet loss rate in the PGM network.

[0068] Figure 6 Schematic diagram of a device embodiment for reducing congestion in a practical general multicast network provided by an embodiment of the present disclosure. The device 60 can be applied as a switching device outside the aggregation point in a PGM network. The device 60 includes a processor 61, a machine-readable storage medium 62, a switching chip 63, and a network interface 64.

[0069] The processor 61 performs the following operations by running the machine executable instructions recorded in the machine readable storage medium 62: establishing a pair of first segment statistical flow table entries and a tail segment statistical flow table for the specified multicast group; based on the first segment statistical flow table entries, counting the number of messages of the first part of the original data messages of the service flow of the specified multicast group; based on the tail segment statistical flow table entries, counting the number of messages of the second part of the original data messages of the service flow of the specified multicast group.

[0070] The processor 61 runs the machine executable instructions recorded in the machine-readable storage medium 62, and also performs the following operations: sending a flow head segment message count notification message to the aggregation point; the flow head segment message count notification message carries the number of original data messages of the first part of the business flow; the number of original data messages of the first part of the statistical business flow is cleared to zero; sending a flow tail segment message count notification message to the aggregation point, and clearing the number of original data messages of the second part of the statistical business flow to zero.

[0071] The processor 61 also performs the following operations by running the machine executable instructions recorded in the machine readable storage medium 62: receiving a negative acknowledgment message; and sending a negative acknowledgment message to the convergence point.

[0072] In the present disclosure, a machine-readable storage medium may be any electronic, magnetic, optical or other physical storage device for storing or containing information (such as executable instructions, data, etc.). For example, any machine-readable storage medium herein may be any type of random access memory (RAM), volatile memory, non-volatile memory, flash memory, storage drive (such as a hard drive), solid-state drive, any type of storage optical disk (such as a CD, DVD, etc.), and similar devices, or a combination thereof. In addition, any machine-readable storage medium herein may be a non-temporary machine-readable storage medium.

[0073] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.

Claims

1. A method for shortening the congestion of a practical general multicast network, characterized in that: The method comprises, Each switching device sends a flow head segment message count notification message and a flow tail segment message count notification message to the convergence point in the PGM network; wherein the flow head segment message count notification message and the flow tail segment message count notification message respectively carry the count value of the first part of the original data message and the count value of the second part of the original data message of each service flow of the specified multicast group; The convergence point calculates the end-to-end packet loss rate in the PGM network based on the flow head segment message count notification message or the flow tail segment message count notification message of each switching device; The convergence point sends a flow control notification message of the highest end-to-end packet loss rate to the multicast source; The multicast source reduces the sending rate of the designated multicast group based on the flow control notification message.

2. The method according to claim 1, characterized in that Before the convergence point sends a flow control notification message of the highest end-to-end packet loss rate to the multicast source, the method further includes: Each switching device sends a negative response message received from any multicast receiver to the aggregation point; The packet loss rate of the negative response message stripped by the convergence point; The convergence point sends a negative response message stripped of the packet loss rate to the multicast source.

3. The method according to claim 2, characterized in that Before the convergence point strips off the packet loss rate of the negative acknowledgment message, the method further includes: The convergence point identifies the multicast receiver that sends the NAK message; The convergence point identifies a directly connected switching device of the multicast receiver; The convergence point calculates the packet loss rate of the directly connected switching device based on the count value of the first part of the original data message and the count value of the second part of the original data message notified by the directly connected switching device; The convergence point determines that the packet loss rate of the directly connected switching device is less than the packet loss rate carried by the negative acknowledgment message, and identifies that the packet loss rate carried by the negative acknowledgment message is the highest end-to-end packet loss rate.

4. The method according to claim 2, characterized in that: The method further includes, the convergence point identifying the multicast receiver that sends the NAK message; The convergence point identifies a directly connected switching device of the multicast receiver; The convergence point calculates the packet loss rate of the directly connected switching device based on the count value of the first part of the original data message and the count value of the second part of the original data message notified by the directly connected switching device; The convergence point determines that the packet loss rate of the directly connected switching device is equal to the packet loss rate carried by the negative response message, and identifies the highest end-to-end packet loss rate when calculating the end-to-end packet loss rate in the PGM network.

5. The method according to claim 1, characterized in that: Each switching device establishes a pair of first segment statistical flow table entries and a flow tail segment statistical flow table for the designated multicast group; Each switching device counts the number of packets of the first part of the original data packets of each service flow based on the first segment statistical flow entry; Based on the tail segment statistical flow table entry, counting the number of packets of the second part of the original data packets of each service flow; After each switching device sends the notification message for counting the first segment of the sending flow, the number of messages of the first part of the original data messages of each service flow is cleared; After sending the flow tail segment message count notification message, the number of messages counted in the second part of the original data messages of each business flow is cleared to zero.

6. A device for reducing congestion in a practical general multicast network, characterized in that: The device includes a processor, a machine-readable storage medium, a memory, a switching chip, and a network interface; the processor performs the following operations by running the machine-executable instructions recorded in the machine-readable storage medium: Receive a flow head segment message count notification message and a flow tail segment message count notification message from each switching device in the PGM network; wherein the flow head segment message count notification message and the flow tail segment message count notification message respectively carry the count value of the first part of the original data message and the count value of the second part of the original data message of each service flow of the specified multicast group; Calculate the end-to-end packet loss rate in the PGM network based on the flow head segment message count notification message or the flow tail segment message count notification message from each switching device; Send a flow control notification message with the highest end-to-end packet loss rate to the multicast source.

7. The device according to claim 6, characterized in that The processor further performs the following operations before executing the operation of sending the flow control notification message of the highest end-to-end packet loss rate to the multicast source by running the machine executable instructions recorded in the machine readable storage medium: Receiving a negative acknowledgment message; Stripping the packet loss rate of the negative response message; A negative response message stripped of the packet loss rate is sent to the multicast source.

8. The device according to claim 7, characterized in that The processor further performs the following operations before stripping the packet loss rate of the negative acknowledgment message by running the machine executable instructions recorded in the machine readable storage medium: Identifying the multicast receiver that sends the NAK message; Identifying a directly connected switching device of the multicast receiver; Calculate the packet loss rate of the direct switching device based on the count value of the first part of the original data packets and the count value of the second part of the original data packets notified by the direct switching device; It is determined that the packet loss rate of the directly connected switching device is less than the packet loss rate carried by the negative acknowledgment message, and the packet loss rate carried by the negative acknowledgment message is identified as the highest end-to-end packet loss rate.

9. The device according to claim 7, characterized in that The processor further performs the following operations by running the machine executable instructions recorded in the machine readable storage medium: Identifying the multicast receiver that sends the NAK message; Identifying a directly connected switching device of the multicast receiver; Calculate the packet loss rate of the direct switching device based on the count value of the first part of the original data packets and the count value of the second part of the original data packets notified by the direct switching device; It is determined that the packet loss rate of the directly connected switching device is equal to the packet loss rate carried by the negative response message, and the highest end-to-end packet loss rate is identified when calculating the end-to-end packet loss rate in the PGM network.

10. A device for reducing congestion in a practical general multicast network, characterized in that: The device includes a processor, a machine-readable storage medium, a memory, a switching chip, and a network interface; the processor performs the following operations by running the machine-executable instructions recorded in the machine-readable storage medium: A pair of first segment statistics flow table entries and a flow tail segment statistics flow table are established for the specified multicast group; Based on the first segment statistical flow entry, counting the number of packets of the first part of the original data packets of the service flow of the specified multicast group; Based on the tail segment statistical flow entry, the number of the second part of the original data packets of the service flow of the designated multicast group is counted.

11. The device according to claim 10, characterized in that The processor further performs the following operations by running the machine executable instructions recorded in the machine readable storage medium: Sending a flow first segment message count notification message to the convergence point; the flow first segment message count notification message carries the number of messages of the first part of the original data message of the service flow; Clearing the number of packets of the first part of the original data packets of the service flow to zero; A flow tail segment message count notification message is sent to the convergence point to clear the number of messages counted for the second part of the original data messages of the service flow to zero.

12. The device according to claim 10, characterized in that The processor further performs the following operations by running the machine executable instructions recorded in the machine readable storage medium: Receiving a negative acknowledgment message; Send the negative response message to the convergence point.

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