CN116032842A

CN116032842A - Congestion fault tolerance method, network device, storage medium and computer program product

Info

Publication number: CN116032842A
Application number: CN202211702346.7A
Authority: CN
Inventors: 冯莹; 王俊杰; 成伟
Original assignee: Suzhou Centec Communications Co Ltd
Current assignee: Suzhou Centec Communications Co Ltd
Priority date: 2022-12-28
Filing date: 2022-12-28
Publication date: 2023-04-28

Abstract

The application discloses a congestion fault tolerance method, network equipment, a storage medium and a computer program product, and relates to the field of computers. The method comprises the following steps: and when the PFC state of the second device is abnormal, the ECN congestion mark of the first device is not triggered. The PFC state of the second device can be determined according to the PFC back-pressure frame sent by the second device, when the PFC state of the second device is abnormal, the PFC back-pressure frame is frequently triggered or the PFC back-pressure frame is triggered under the condition of large-scale networking, so that the ECN of the first device is prevented from being influenced by the PFC state abnormality, ECN error marking is carried out, and the fault tolerance of congestion marking is improved.

Description

Congestion fault tolerance method, network device, storage medium and computer program product

Technical Field

The present invention relates to the field of computer technologies, and in particular, to a congestion fault tolerance method, a network device, a storage medium, and a computer program product.

Background

Currently, in order to solve the problem of network congestion. When the bandwidth of the forwarded data packet exceeds the port forwarding capability, a back pressure frame based on congestion marking displaying congestion indication (Explicit Congestion Notification, ECN) and sending priority based flow control (Priority Flow Control, PFC) to the previous hop network device. However, under large-scale networking, there is a risk of PFC deadlock, and frequent triggering of PFC backpressure frames, or triggering of PFC deadlock, may result in a probability that the ECN congestion mechanism is marked with errors, so that the ECN congestion mechanism falls into a chaotic state. Therefore, how to avoid the error marking of the ECN congestion mechanism and improve the fault tolerance of the congestion marking are the problems to be solved.

Disclosure of Invention

The application provides a congestion fault-tolerant method, network equipment, a storage medium and a computer program product, which solve the problem of how to avoid error marking of an ECN congestion mechanism and improve the fault tolerance of congestion marking.

In a first aspect, a congestion fault tolerance method is provided, the method including: receiving a priority-based flow control (PFC) backpressure frame sent by a second device; determining the PFC state of the second device according to the PFC backpressure frame; when the PFC state of the second device is abnormal, the display of congestion indication (ECN) congestion flag is not triggered.

With reference to the first aspect, in one possible implementation manner, the frequency and/or the number of PFC backpressure frames received in a preset period are counted; and indicating that the PFC state of the second device is abnormal when the frequency and/or the number of PFC backpressure frames is greater than the PFC threshold.

With reference to the first aspect, in another possible implementation manner, when the PFC state of the second device is normal, a target queue depth of an output port of the first device is detected; the ECN congestion marking is triggered when the target queue depth of the egress port of the first device exceeds an ECN threshold.

With reference to the first aspect, in another possible implementation manner, when the PFC state of the second device is normal, sending of data to the second device is stopped.

In a second aspect, a congestion fault tolerance apparatus is provided, including a receiving module, a determining module, and a processing module.

The receiving module is configured to receive a priority-based flow control (PFC) backpressure frame sent by a second device.

The determining module is used for determining the PFC state of the second device according to the PFC back-pressure frame.

The processing module is configured to not trigger display of a congestion indication (ECN) congestion flag when the PFC state of the second device is abnormal.

With reference to the second aspect, in one possible implementation manner, the determining module is further configured to count a frequency and/or a number of PFC counter-pressure frames received in a preset period; and indicating that the PFC state of the second device is abnormal when the frequency and/or the number of PFC backpressure frames is greater than the PFC threshold.

With reference to the second aspect, in another possible implementation manner, the processing module is further configured to detect a target queue depth of an output port of the first device when a PFC state of the second device is normal; the ECN congestion marking is triggered when the target queue depth of the egress port of the first device exceeds an ECN threshold.

With reference to the second aspect, in another possible implementation manner, the processing module is further configured to stop sending data to the second device when the PFC state of the second device is normal.

In a third aspect, a computer device is provided, the computer device comprising a processor, an ECN module, a communication interface, and a memory, the memory for storing computer instructions; the communication interface is used for receiving the PFC back-pressure frame; the processor is configured to determine a PFC state of the second device according to a frequency and/or a number of PFC backpressure frames received within a preset period, and when the processor executes a set of computer instructions, perform functions of each module of the method of the first aspect or any one of possible implementations of the first aspect; the ECN module is used for determining ECN congestion marks of the network equipment according to the PFC state of the second equipment, when the PFC state of the second equipment is abnormal, the ECN congestion marks are not triggered, and when the PFC state of the second equipment is normal, the target queue depth of the outlet port of the first equipment is detected; the ECN congestion marking is triggered when the target queue depth of the egress port of the first device exceeds an ECN threshold.

In a fourth aspect, a computer-readable storage medium is provided, comprising computer software instructions; the computer software instructions, when run in a computer, cause the computer to perform the method as claimed in the first aspect or any of the possible implementations of the first aspect.

In a fifth aspect, there is provided a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of the first aspect or any implementation of the first aspect.

Further combinations of the present application may be made to provide further implementations based on the implementations provided in the above aspects.

Drawings

Fig. 1 is a schematic diagram of a PFC back pressure provided herein;

fig. 2 is a flow chart of a congestion fault-tolerant method provided in the present application;

FIG. 3 is a schematic diagram of an exchange chip provided in the present application;

fig. 4 is a schematic diagram of a transmission packet provided in the present application;

fig. 5 is a schematic structural diagram of a congestion fault-tolerant device provided in the present application;

fig. 6 is a schematic diagram of a computer device provided in the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

For the convenience of understanding the solution of the embodiments of the present application, a brief description of related concepts is given below:

network congestion refers to that when the bandwidth of a forwarding data packet in a network exceeds the port forwarding capability, the data packet forwarding delay is increased due to limited queue buffer resources of a network switch, and even packet loss retransmission occurs in severe cases, congestion is further aggravated, and the service is interrupted.

Priority-based flow control (Priority Flow Control, PFC) in which when a downstream device in the network finds that its flow receiving capability is less than the first device's transmitting capability, it will actively send a Pause frame to the first device requesting the first device to Pause the flow transmission, waiting for a period of time and continuing the transmission.

As shown in fig. 1, the output port of the first device is divided into 8 priority queues, the input port of the second device has 8 receiving buffers, and the output port of the first device corresponds to the input port of the second device one by one. When a certain buffer queue on an ingress port of the second device is congested, for example, a first queue, and when the ingress port queue length of the first queue in the second device exceeds a preset threshold value, the second device triggers PFC to send a PFC back-pressure frame to the first device, where the PFC back-pressure frame is used to make the first queue of the first device suspend sending data packets, and other queues still send data normally. And when the length of the second equipment inlet port queue is lower than another set threshold value, the first queue of the second equipment transmits a RESUME frame, and the first queue of the first equipment RESUMEs transmitting the data packet.

However, after the first device receives the PFC backpressure frame, it stops sending or delays sending data according to backpressure information indicated by the PFC backpressure frame, and stores the data in a local port buffer queue, if the consumption of the local port buffer queue exceeds a threshold value, it continues to backpressure the previous device, so as to perform one-level backpressure until the backpressure indicates to the source server, thereby eliminating packet loss caused by congestion of the network node.

In order to solve the problem of how to avoid the error marking of the ECN congestion mechanism and improve the fault tolerance of the congestion marking, the embodiment of the application provides a congestion fault tolerance method, namely, when the second device sends congestion, a PFC back pressure frame sent by the second device is received, the PFC state of the second device is determined according to the PFC back pressure frame, and when the PFC state of the second device is abnormal, the ECN congestion marking of the first device is not triggered. The PFC state of the second device can be determined according to the PFC back-pressure frame sent by the second device, when the PFC state of the second device is abnormal, the PFC back-pressure frame is frequently triggered or the PFC back-pressure frame is triggered under the condition of large-scale networking, so that the ECN of the first device is prevented from being influenced by the PFC state abnormality, ECN error marking is carried out, and the fault tolerance of congestion marking is improved.

Next, a congestion fault tolerance method will be described in detail with reference to the accompanying drawings. Fig. 2 is a flow chart of a congestion fault-tolerant method according to an embodiment of the present application, and fig. 3 is a schematic diagram of a switching chip according to the present application. The first device and the second device are described herein as being switches.

Step 210, receiving a PFC backpressure frame sent by the second device.

When the bandwidth of the data packet sent by the source server exceeds the port forwarding capacity of the second device, the second device judges according to the priority of the received message, so that the processing mode of the message is determined.

In one embodiment, if the priority of the received message has an enabled PFC, the message is received, and a PFC backpressure frame is sent to the first device, informing the first device to temporarily stop sending the message. After receiving the PFC backpressure frame, the first device temporarily stops sending the packet to the local terminal, and the pause time length information is carried by the PFC backpressure frame. While congestion is still present, this process will repeat until congestion is relieved.

In another embodiment, if the priority of the received message does not enable PFC, the message is directly discarded.

As shown in fig. 4, the source server sends 10Gbps of data to the destination server, and the data is forwarded through the first device first, and because the bandwidth of the output port of the first device is 10Gbps, the first device is not congested, and ECN congestion marking is not triggered. The first device continues to forward the 10Gbps data to the second device, and the second device triggers the ECN congestion flag because the bandwidth of the output port of the second device is only 1Gbps, and the second device sends the PFC back pressure frame to the first device in the ingress direction because the output port of the second device continues to be congested.

PFC allows 8 virtual channels to be created on one ethernet link (i.e., 8 virtual channels to be created between a first device and a second device), and each virtual channel is assigned a corresponding priority, allowing any one of the virtual channels to be individually suspended and restarted, while allowing traffic for the other virtual channels to pass uninterrupted.

Although PFC can achieve queue-based flow control by mapping different priorities to different queues, new problems, such as PFC deadlock, are introduced at the same time. PFC deadlock refers to a network state in which when multiple switches are simultaneously congested due to a loop or the like, respective port buffers consume more than a threshold value, and wait for each other to release resources, thereby causing permanent blocking of data flows on all switches.

Therefore, after the first device receives the PFC backpressure frame sent by the second device, the first device needs to determine the PFC state of the second device according to the PFC backpressure frame, so as to avoid causing the first device to perform erroneous ECN congestion marking under the condition that PFC deadlock or second device failure occurs.

Step 220, determining the PFC state of the second device according to the PFC backpressure frame.

Under normal conditions, when the second device is congested, the ingress port of the second device sends a PFC backpressure frame to the first device according to a preset frequency, and when the second device is congested, the sending of the PFC backpressure frame to the first device is stopped. Under the condition that PFC deadlock or second equipment failure occurs, the second equipment continuously sends PFC back-pressure frames to the first equipment, so that the first equipment can carry out ECN congestion marking every time the PFC back-pressure frames sent by the second equipment are received, and then an ECN congestion mechanism is caused to enter a chaotic state. Thus, after receiving the PFC backpressure frame sent by the second device, the PFC state of the second device is determined according to the PFC backpressure frame.

Specifically, the first device counts the frequency and/or the number of the received PFC counterpressure frames in the preset period, and the first device receives the PFC counterpressure frames sent by the second device at the normal frequency, so that the first device has a small number of PFC counterpressure frames as a normal condition, when the number of PFC counterpressure frames is obviously excessive, and the port flow of PFC backpressure is weakened or even stopped, that is, when the frequency and/or the number of PFC counterpressure frames is greater than the PFC threshold, the PFC state of the second device is indicated to be abnormal. And when the frequency and the number of PFC backpressure frames are smaller than the PFC threshold, indicating that the PFC state of the second device is normal.

Step 230, when the PFC state of the second device is abnormal, the ECN congestion flag is not triggered.

And because the PFC state of the second device is abnormal, continuously sending a PFC back-pressure frame to the first device, and if the first device continuously responds to the PFC back-pressure frame sent by the second device, performing ECN congestion marking. When PFC and ECN are used simultaneously in networking, PFC is typically validated over ECN due to the longer validation time of ECN. The PFC performs hop-by-hop backpressure to the first device based on the port, which may cause other flows with the same priority to be affected, and further cause ECNs of flows with the same priority of the previous hop device to be marked by errors, thereby causing ECN congestion to enter a chaotic state. Therefore, when the PFC state of the second device is abnormal, the ECN congestion mark is not triggered, so that the fault tolerance of ECN congestion can be effectively improved, and the ECN congestion is prevented from entering a chaotic state.

And 240, when the PFC state of the second device is normal, performing ECN congestion marking according to the target queue depth of the outlet port of the first device.

When the frequency and the number of the PFC back-pressure frames are smaller than the PFC threshold, the PFC state of the first device is indicated to be normal, the PFC back-pressure frames sent by the first device can be responded, and the processing mode of the message can be determined according to the configuration information and the state information of the priority of the second device.

If the first device has the PFC function of starting the corresponding priority and does not pause sending the message with the corresponding priority, the sending of the message with the corresponding priority is paused, and a timer is started according to the pause time corresponding to the PFC back-pressure frame. When the timer expires, the transmission of the corresponding priority message will resume.

If the first device has the PFC function of starting the corresponding priority and has paused sending the message of the corresponding priority, updating the expiration time of the corresponding timer according to the pause time corresponding to the PFC back-pressure frame.

If the corresponding pause time in the PFC back-pressure frame is 0, the corresponding pause timer is expired immediately, and the transmission of the corresponding priority message is resumed immediately.

If the corresponding pause time in the PFC backpressure frame is not 0, the corresponding pause timer is reset. That is, as long as the second device is always congested, the first device may continuously suspend sending the message of the corresponding priority due to continuously receiving PFC backpressure frames.

If the first device does not start the PFC function of the corresponding priority, the sending of the message of the corresponding priority is not suspended.

At the same time, ECN congestion marking is also required according to the target queue depth of the egress port of the first device. When the target queue depth of the outlet port of the first device exceeds a threshold value, carrying the congestion information of the first device to the second device through an ECN field in the IP message, and forwarding the congestion information to a destination server through the network device along the way. And the destination server adjusts the sending rate of the source server by sending a congestion notification message to the source server according to the frequency of the ECN mark carried by the received message.

The DSCP field in the IP packet header has 2 bits to identify the ECN. These 2 bits represent respectively: ECN transport (ECNCapableTransport, ECT) and congestion (CongestionExperienced, CE) are supported. Specifically, when ECT is 0 and ce is 0, it indicates that the IP packet does not support ECN; when ECT is 0 and CE is 1, the ECN is supported by the IP message; when ECT is 1 and CE is 0, the ECN is supported by the IP message; when ECT is 1 and ce is 1, it means that the IP packet supports ECN and congestion occurs.

ECN is that when a message congestion occurs at the exit of the network device, ECN field of the header of an IP message that enables ECN (when the ECN field of the IP message is 01 or 10, indicating that ECN is enabled) is marked with ecn=11, which indicates that the IP message encounters network congestion, and the IP message is not discarded by WRED mechanism. If the destination server finds that the ECN field of the IP message is marked as 11, a congestion notification message is immediately generated, the message is sent to the source server, the congestion notification message contains the congested data flow information, and after the remote server receives the congestion notification message, the link network equipment is congested by reducing the corresponding data flow sending rate, so that packet loss is avoided.

It will be appreciated that, in order to implement the functions of the above embodiments, the computer includes corresponding hardware structures and/or software modules that perform the respective functions. Those of skill in the art will readily appreciate that the elements and method steps of the examples described in connection with the embodiments disclosed herein may be implemented as hardware or a combination of hardware and computer software. Whether a function is implemented as hardware or computer software driven hardware depends upon the particular application scenario and design constraints imposed on the solution.

Fig. 5 is a schematic structural diagram of a congestion fault-tolerant device according to an embodiment of the present application. These congestion fault-tolerant means may be used to implement the functions of the first device or the second device in the above method embodiments, so that the beneficial effects of the above method embodiments may also be implemented.

As shown in fig. 5, the congestion fault tolerance apparatus 500 includes a receiving module, a determining module, and a processing module. The congestion fault tolerance device 500 is used to implement the functionality of the first device or the second device in the method embodiment shown in fig. 2 described above.

When the congestion fault tolerance apparatus 500 is used to implement the functionality of the first device or the second device in the method embodiment shown in fig. 2: a receiving module 501, a determining module 502 and a processing module 503.

The receiving module 501 is configured to receive a priority-based flow control (PFC) backpressure frame sent by a second device.

The determining module 502 is configured to determine a PFC state of the second device according to the PFC backpressure frame.

The processing module 503 is configured to not trigger displaying a congestion indication (ECN) congestion flag when the PFC state of the second device is abnormal.

The determining module 502 is further configured to count a frequency and/or a number of PFC backpressure frames received in a preset period; and indicating that the PFC state of the second device is abnormal when the frequency and/or the number of PFC backpressure frames is greater than the PFC threshold.

The processing module 503 is further configured to detect a target queue depth of the egress port of the first device when the PFC state of the second device is normal; the ECN congestion marking is triggered when the target queue depth of the egress port of the first device exceeds an ECN threshold.

The processing module 503 is further configured to stop sending data to the second device when the PFC state of the second device is normal.

The above-mentioned receiving module 501, determining module 502 and processing module 503 may be directly described with reference to the related description in the method embodiment shown in fig. 2, which is not repeated herein.

Fig. 6 provides a computer device. The computer device 600 shown in fig. 6 may be used in particular to implement the functionality of the congestion fault-tolerance apparatus 500 described above in the embodiment shown in fig. 5.

The computer device 600 includes a bus 601, a processor 602, a communication interface 603, and a memory 604. The processor 602, the memory 604 and the communication interface 603 communicate with each other via a bus 601. The bus 601 may be a peripheral component interconnect standard (peripheral component interconnect, PCI) bus or an extended industry standard architecture (extended industry standard architecture, EISA) bus, or the like. The buses may be divided into address buses, data buses, control buses, etc. For ease of illustration, only one thick line is shown in fig. 6, but not only one bus or one type of bus. The communication interface 603 is used for communicating with the outside, for example, receiving an IP message or PFC back-pressure frame.

The processor 602 may be a central processing unit (central processing unit, CPU), where the processor 602 is configured to receive a PFC backpressure frame sent by the second device when the second device sends congestion, determine a PFC state of the second device according to the PFC backpressure frame, not trigger an ECN congestion flag of the first device when the PFC state of the second device is abnormal, and detect a target queue depth of an egress port of the first device when the PFC state of the second device is normal; the ECN congestion marking is triggered when the target queue depth of the egress port of the first device exceeds an ECN threshold. The memory 604 may include volatile memory (RAM), such as random access memory (random access memory). The memory 604 may also include a non-volatile memory (non-volatile memory), such as read-only memory (ROM), flash memory, HDD, or SSD.

The memory 604 has stored therein executable code that the processor 602 executes to perform the aforementioned congestion fault tolerance method.

In particular, in the case where the embodiment shown in fig. 5 is implemented, and where the modules described in the embodiment of fig. 5 are implemented by software, the memory 604 stores software or program codes required to perform the functions of the receiving module 501, the determining module 502, and the processing module 503 in fig. 5, and the processor 602 is configured to execute instructions in the memory 604 to perform a congestion fault-tolerant method applied to the congestion fault-tolerant apparatus 500.

The present application also provides a computer readable storage medium comprising instructions that, when executed on a computer, cause the computer to perform the above-described method of congestion fault tolerance applied to the congestion fault tolerance apparatus 400.

The present application also provides a computer program product which, when executed by a computer, performs any of the methods described above. The computer program product may be a software installation package, which may be downloaded and executed on a computer in case any of the methods described above is required.

It should be further noted that the above-described apparatus embodiments are merely illustrative, and that the units described as separate units may or may not be physically separate, and that units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the drawings of the embodiment of the device provided by the application, the connection relation between the modules represents that the modules have communication connection therebetween, and can be specifically implemented as one or more communication buses or signal lines.

From the above description of the embodiments, it will be apparent to those skilled in the art that the present application may be implemented by means of software plus necessary general purpose hardware, or of course may be implemented by dedicated hardware including application specific integrated circuits, dedicated CPUs, dedicated memories, dedicated components and the like. Generally, functions performed by computer programs can be easily implemented by corresponding hardware, and specific hardware structures for implementing the same functions can be varied, such as analog circuits, digital circuits, or dedicated circuits. However, a software program implementation is a preferred embodiment in many cases for the present application. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art in the form of a software product stored in a readable storage medium, such as a floppy disk, a usb disk, a removable hard disk, a ROM, a RAM, a magnetic disk or an optical disk of a computer, etc., including several instructions for causing a computer device (which may be a personal computer, a training device, or a network device, etc.) to perform the method described in the embodiments of the present application.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product.

The computer program product includes one or more computer instructions. When loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present application, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website, computer, training device, or data center to another website, computer, training device, or data center via a wired (e.g., coaxial cable, optical fiber, digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be stored by a computer or a data storage device such as a training device, a data center, or the like that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., a floppy Disk, a hard Disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a Solid State Disk (SSD)), or the like.

Claims

1. A network device comprising a processor and a display congestion indication (ECN) module, the processor configured to:

receiving a priority-based flow control (PFC) backpressure frame sent by a second device;

determining the PFC state of the second device according to the PFC backpressure frame;

the ECN module is used for: determining an ECN congestion flag of the network device according to the PFC state of the second device;

when the PFC state of the second device is abnormal, the display of a congestion indication (ECN) congestion flag is not triggered.

2. The network device of claim 1, wherein the processor is specifically configured to:

counting the frequency and/or the number of the PFC backpressure frames received in a preset period;

and when the frequency and/or the number of the PFC backpressure frames are/is larger than a PFC threshold value, indicating that the PFC state of the second equipment is abnormal.

3. The network device of claim 2, wherein the ECN module is specifically configured to:

when the PFC state of the second device is normal, detecting the target queue depth of the outlet port of the first device;

and triggering ECN congestion marking when the target queue depth of the outlet port of the first equipment exceeds an ECN threshold value.

4. The network device of claim 2, wherein the ECN module is specifically configured to:

and when the PFC state of the second equipment is abnormal, the ECN congestion mark is not triggered.

5. A method of congestion fault tolerance, applied to a first device, comprising:

receiving a priority-based flow control (PFC) backpressure frame sent by a second device when the ECN of the first device is not marked;

6. The method of claim 5, wherein determining the PFC state of the second device from the PFC backpressure frame comprises:

7. The method of claim 5, wherein the method further comprises:

8. The method of claim 5, wherein the method further comprises:

and stopping sending data to the second equipment when the PFC state of the second equipment is normal.

9. A computer readable storage medium storing computer instructions which, when run on a computer device, cause the computer to perform the method of any of claims 5-8.

10. A computer program product comprising a computer program which, when executed by a processor, implements the method of any of claims 5-8.