CN115665066A

CN115665066A - Method, equipment and medium for expanding MAC address table capacity

Info

Publication number: CN115665066A
Application number: CN202211307836.7A
Authority: CN
Inventors: 刘宏强
Original assignee: Inspur Cisco Networking Technology Co Ltd
Current assignee: Inspur Cisco Networking Technology Co Ltd
Priority date: 2022-10-25
Filing date: 2022-10-25
Publication date: 2023-01-31

Abstract

The application discloses a method, equipment and medium for expanding the capacity of an MAC address table, wherein the method comprises the following steps: receiving an unknown MAC message of a PC (personal computer) end through a switch, and acquiring basic information according to the unknown MAC message, wherein the basic information comprises but is not limited to a source MAC address; adding the basic information into an address table, and judging whether the basic information is successfully added; and if the basic information is not successfully added, calling an ACL table of the switch to enable the destination MAC address of the PC end to be the same as the source MAC address through the ACL table. According to the method and the device, the MAC table is expanded by utilizing the ACL resource of the switching chip, the flooding of the message is reduced while the MAC table entry is increased, the occupation of extra bandwidth caused by flooding is reduced, the stability of the network is enhanced, the occurrence of network congestion is reduced, and the transmission quality of the network is improved.

Description

Method, equipment and medium for expanding MAC address table capacity

Technical Field

The present application relates to the field of computer technologies, and in particular, to a method, an apparatus, and a medium for expanding the capacity of an MAC address table.

Background

The MAC address is an address used to identify the location of the network device. In the current market, the sizes of the MAC address table entries in the switch chip are fixed, the entries cannot be learned after being learned, and the remained unlearned traffic cannot find the corresponding MAC table, so that the switch can flood in the same forwarding domain. Flooding in the network occupies a large amount of bandwidth, which easily causes congestion and packet loss, and affects network performance.

Disclosure of Invention

In order to solve the above problem, the present application provides a method for expanding the capacity of a MAC address table, including: receiving an unknown MAC message of a PC (personal computer) end through a switch, and acquiring basic information according to the unknown MAC message, wherein the basic information comprises but is not limited to a source MAC address; adding the basic information to an address table, and judging whether the basic information is added successfully; and if the basic information is not successfully added, calling an ACL table of the switch so as to enable the destination MAC address of the PC end to be the same as the source MAC address through the ACL table.

In one example, the ACL table includes a plurality of ACL entry items, the ACL entry items including a first matching entry and a second matching entry; calling an ACL table of the switch, specifically comprising: determining the first matching item, wherein the first matching item includes but is not limited to the source MAC address, setting the action of the first matching item to cancel an upper CPU, and determining Stats statistic corresponding to the ACL table entry; and determining the second matching item, wherein the second matching item comprises but is not limited to the destination MAC address, and setting the action of the second matching item as redirection so that the destination MAC address of the PC end is the same as the source MAC address.

In one example, the method further comprises: determining a state matching item in the second matching item through the ACL table so as to search whether the destination MAC address is included in an MAC table of the switch through the state matching item; if the MAC table comprises the destination MAC address, the switch is enabled to hit the destination MAC address in the MAC table, and the ACL table item corresponding to the destination MAC address is deleted.

In one example, after invoking the ACL table of the switch, the method further comprises: receiving a first access message of the PC terminal through the switch, acquiring a first destination MAC address according to the first access message, and hitting the first destination MAC address in the ACL table through the switch so as to forward the first access message according to the first destination MAC address; receiving a second access message for accessing the PC terminal through the switch, acquiring the destination MAC address according to the second access message, hitting the destination MAC address in the ACL table through the switch to redirect to a port of the PC terminal, and forwarding the second access message to the PC terminal.

In one example, the method further comprises: determining a preset aging rule, and traversing the ACL table at regular time according to the aging rule; acquiring a real-time Stats statistical value and a historical Stats statistical value of an ACL table entry in the ACL table, and comparing the real-time Stats statistical value with the historical Stats statistical value; if the real-time Stats statistic value is different from the historical Stats statistic value, the real-time Stats statistic value is stored; and if the real-time Stats statistic is the same as the historical Stats statistic, deleting the ACL table entry.

In one example, deleting the ACL entry specifically includes: determining the ACL table entry to be deleted, and deleting a first matching item, a second matching item and Stats resources corresponding to the ACL table entry.

In one example, the method further comprises: receiving a drift message of a rear PC (personal computer) end through the switch, and acquiring basic information of the rear PC end according to the drift message; determining the corresponding ACL table entry according to the source MAC address, and deleting the ACL table entry; and establishing a new ACL table item according to the basic information of the rear PC end.

In one example, obtaining the basic information of the unknown MAC according to the packet specifically includes: configuring a drifting action according to the source MAC address, and sending the message to a CPU according to the drifting action; and analyzing the message through the CPU to obtain the basic information of the unknown MAC.

On the other hand, the application also provides a device for expanding the capacity of the MAC address table, which includes: at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the apparatus to perform: receiving an unknown MAC message of a PC (personal computer) end through a switch, and acquiring basic information according to the unknown MAC message, wherein the basic information comprises but is not limited to a source MAC address; adding the basic information to an address table, and judging whether the basic information is added successfully; and if the basic information is not successfully added, calling an ACL table of the switch so as to enable the destination MAC address of the PC end to be the same as the source MAC address through the ACL table.

In another aspect, the present application further provides a non-volatile computer storage medium storing computer-executable instructions configured to: receiving an unknown MAC message of a PC (personal computer) end through a switch, and acquiring basic information according to the unknown MAC message, wherein the basic information comprises but is not limited to a source MAC address; adding the basic information to an address table, and judging whether the basic information is added successfully; and if the basic information is not successfully added, calling an ACL table of the switch so as to enable the destination MAC address of the PC end to be the same as the source MAC address through the ACL table.

According to the method and the device, the MAC table is expanded by using the ACL resource of the exchange chip, the flooding of the message is reduced while the MAC table entry is increased, the occupation of extra bandwidth caused by flooding is reduced, the stability of the network is enhanced, the occurrence of network congestion is reduced, and the transmission quality of the network is improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 is a diagram illustrating the structure of a MAC in an embodiment of the present application;

fig. 2 is a schematic structural diagram of traffic flooding forwarding in the embodiment of the present application;

fig. 3 is a flowchart illustrating a method for expanding the capacity of a MAC address table according to an embodiment of the present application;

fig. 4 is a structural diagram of new MAC learning in the embodiment of the present application;

FIG. 5 is a diagram illustrating the structure of MAC aging in the embodiment of the present application;

fig. 6 is a schematic structural diagram of MAC address drift in the embodiment of the present application;

FIG. 7 is a diagram illustrating address drift of a conventional MAC table in an embodiment of the present application

FIG. 8 is a schematic diagram illustrating address drift of an ACL entry in an embodiment of the present application;

fig. 9 is a schematic diagram of an apparatus for expanding the capacity of a MAC address table in the embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail and completely with reference to the following specific embodiments of the present application and the accompanying drawings. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The technical solutions provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings.

As shown in fig. 1, the MAC table is an important table item forwarded by the second layer of the switch chip, for example, N PC terminals belong to VLAN1, and the corresponding MACs are a, B, \ 8230 \ 8230;, N, respectively. The MAC addresses learned at the switch are as shown in the table below.

When the PC1 accesses the PCN, the message is sent to the switch, the table entry with the destination MAC being N and the VLAN being 1 is searched, and the exit being PORT N can be searched. If the PC1 is an unknown address and the MAC address of the PC1 does not exist in the MAC table of the switch, the MAC address of the PC1 is learned and added into the MAC table, and then the message is forwarded from the PORT N. In this case, the traffic will not flood in the VLAN, and other PCs will not receive the traffic.

As shown in fig. 2, when the MAC address table of the switch is full, as shown in the following table.

MAC address	VLAN	Port(s)
			A	1	1
B	1	2
			……	……	……
N	1	N

Suppose a PCk is newly accessed, the MAC address is K, and the access is on PORT K. At this time, if the PC1 accesses the PC K, the packet arrives at the switch, the entry of the destination MAC K and the VLAN1 is searched, and as a result, the switch floods the VLAN1, and all other PCs in the VLAN1 receive a flow. PCk also receives a copy and replies to PC1 with a message. If the forwarded traffic in the switch is not large, the communication between PC1 and PCk is not affected, but occupies a lot of bandwidth.

Therefore, the switch basically does not process the full table, and is free from message flooding, or shortens the aging time of the MAC table entry, so that the unused MAC is aged as soon as possible, or the equipment with larger MAC table entries is replaced. Flooding in the network occupies a large amount of bandwidth, which easily causes congestion and packet loss and affects the network performance; extra investment cost is also needed for replacing equipment with larger MAC table items; and cannot be aged if the devices are all communicating online.

As shown in fig. 3, in order to solve the above problem, a method for expanding the capacity of a MAC address table provided in an embodiment of the present application includes:

s301, an unknown MAC message of a PC end is received through a switch, and basic information is obtained according to the unknown MAC message, wherein the basic information includes but is not limited to a source MAC address.

The switch configures an action of learning new MAC and MAC address drift on a port, the action is COPY-TO-CPU, if an unknown MAC exists, the CPU receives a corresponding unknown MAC message, wherein the unknown MAC is a new MAC which cannot be found in an MAC table or an MAC when the MAC address port is changed. And the CPU controls the learning of the MAC according to the unknown MAC message. The message forwarding module is configured into a COPY-TO-CPU, and the message forwarded by hardware is not influenced.

As shown in fig. 4, if unknown PC1 accesses other machines, the source MAC in the message is MAC a of itself, and when the PORT 1 enters, the chip looks up the MAC table TO find that there is no entry of MAC a + VLAN1 in the MAC table, so that the MAC address needs TO be learned, and since the MAC learning action is COPY-TO-CPU, the chip forwards a normal communication message. Meanwhile, the CPU receives the message of needing to learn the MAC address. After receiving the learned message, the CPU needs to analyze the content of the message to obtain basic information in the message, where the basic information includes a source MAC address, a VLAN, and an incoming port number.

And calling a switching chip interface and adding the switching chip interface into a chip MAC address table. As shown in the table below.

MAC address	VLAN	Port
			A	1	1

S302, adding the basic information to an address table, and judging whether the basic information is added successfully.

If the basic information is added successfully, the MAC table is not full or HASH conflict is indicated, and the table entry does not need to be issued to the ACL table.

And S303, if the basic information is not successfully added, calling an ACL table of the switch to enable the destination MAC address of the PC end to be the same as the source MAC address through the ACL table.

If the basic information is not added successfully, the MAC table is full or the HASH conflict bucket is full, an interface of an exchange chip ACL needs to be called, and the MAC table entry is expanded by using chip ACL resources.

In one embodiment, matching ACL entries are as shown in the following table.

Firstly, a first matching item is set, the first matching item matches with a source MAC + VLAN + port of a message, the action is Copy To Cpu Cancel, and the CPU is cancelled. Meanwhile, the ACL needs to bind a Stats statistic for aging use of the MAC table entry. The ACL table includes a plurality of ACL table entries

And then setting a second matching item, wherein the MAC matched with the second matching item is equal to the source MAC + VLAN + DMacLookUpMiss of the message, and the action is redirect port, namely redirecting to the incoming port, so that the destination MAC address of the accessed PC1 is the same as the source MAC address of the PC 1. According to the first matching item and the second matching item, the message of the MAC will not be loaded on the CPU. If the MAC is reversely forwarded, the MAC will not flood when the destination MAC is PC1, and becomes unicast. The method comprises the steps that the DMacLookUpMiss is a state matching item and is used for searching for a missed target MAC in an MAC forwarding table, if the target MAC exists in the MAC table and the ACL, the MAC table is preferentially used for forwarding, and the issued ACL matching does not interfere with the original MAC logic. And the software stores the issued ACL table items for use when the MAC is aged, updated and deleted.

In one embodiment, after the ACL entry is issued, if the PC1 accesses another PC, the switch receives an access message (referred to as a first access message) from the PC1, and acquires an accessed destination MAC address (referred to as a first destination address) according to the first access message, at this time, the switch may hit the first destination address in the ACL table, the message is not loaded to the CPU any more, the statistics of Stats of the ACL increases, and the message is forwarded directly. If the access is in the reverse direction, that is, when the other PC end accesses the PC1, the switch receives an access message (referred to as a second access message herein) from the other PC end, and acquires a destination MAC address (referred to as a second destination address herein) of the access, that is, a source MAC address of the PC1, according to the second access message. Because the MAC table does not have the MAC table entry, the message can be marked with a DMacLookUpMiss state, the target MAC of the message is that A can hit a target MAC address in ACL, the action is that the message is redirected to PORT 1 and is directly forwarded from PORT 1, and flooding can not be carried out in a VLAN. The same forwarding behavior as hitting the destination MAC entry.

In one embodiment, a missed target MAC in an MAC forwarding table is searched through a DMacLookUpMiss state matching item, if the target MAC exists in both the MAC table and the ACL, a switch is made to hit a target MAC address in the MAC table, the MAC table is preferentially used for forwarding, and the ACL table item corresponding to the target MAC address is deleted.

In one embodiment, the MAC table needs to be continuously updated to accommodate changes in the network. The entries automatically generated in the MAC table (i.e., dynamic MAC entries) are not always valid, each entry has a lifetime, and entries that cannot be updated until the lifetime is reached are deleted, which is called an aging time. If the record is updated before the life cycle is reached, the aging time of the entry is recalculated. As shown in fig. 5, when the PC1 goes down, or no data access beyond the set aging time, the aging operation of the MAC will be triggered.

If the MAC of the PC1 is normally issued in the MAC table, the switching chip generally reports an aging interrupt when aging, and at this time, it is sufficient to call the API interface of the relevant switching chip to delete the MAC address.

And globally starting a timer for the MAC table entry in the ACL table, wherein the time interval of the timer is the user-configured aging time and is set to be 300S by default. When the timer is triggered every time, all MAC stored in local software is traversed to learn relevant ACL table items, the real-time Stats statistical value of the current ACL table item is obtained, and the statistical value is compared with the historical Stats value of the ACL table item which is traversed for the last time. If the real-time Stats statistic value is different from the historical Stats statistic value, the fact that the flow hits an ACL table entry in the aging period is shown, and flow forwarding exists, the current Stats value is stored, and the next period is used for comparison. If the real-time Stats statistic value is the same as the historical Stats statistic value, which indicates that no flow is forwarded in the aging period, the MAC needs to be aged, a locally stored ACL entry corresponding to the MAC is searched, and a chip API is called to delete the ACL entry and the corresponding Stats resource.

In one embodiment, when a user needs to manually delete a specified MAC, the chip API is directly called to delete the MAC for the MAC normally learned in the MAC table. For the MAC issued in the ACL table entry, the ACL table entry issued by the corresponding MAC needs to be searched in the stored software table entries. And deleting two ACL table entries issued by the MAC and corresponding stats resources.

In an embodiment, as shown in fig. 6, the MAC address drift refers to a phenomenon that two or three ports in one VLAN on a device learn the same MAC address, and then the learned MAC address table entry covers the original MAC address table entry. The switch receives a drift message of a post-learning PC (referred to as a post-PC) end, and acquires basic information of the post-PC end according to the drift message. As shown in fig. 7, if the MAC entry exists in the conventional MAC table, since the MAC address drift configured with the PORT is COPY-TO-CPU, the MAC a with the source MAC being PC1 received from PORT 2 will forward the message COPY TO CPU, and the message of the hardware is forwarded normally. And acquiring the MAC, VLAN and PORT information of the message, calling a chip API (application program interface), and updating the table entry PORT information in the MAC table to be PORT 2. As shown in fig. 8, if the MAC entry is issued in the ACL entry, since the received message is source MAC + VLAN1+ port 2, the first matching entry of the issued ACL entry cannot be hit. Meanwhile, no hit MAC table entry exists in the MAC table, and the action of the configured PORT MAC address drift is COPY-TO-CPU, the message COPY is sent TO the CPU by the MAC A of which the source MAC is PC1 and received from PORT 2, and the message of the hardware is normally forwarded. And obtaining the MAC, VLAN and port information of the message, searching an ACL table entry corresponding to the MAC, and deleting the table entry and Stats resources. And adding two new ACL entries, and taking the action of source MAC + VLAN1+ port 2 as the cancel of CPU and statistics. The action of the message + VLAN1 of the destination MAC A is from redirect PORT to PORT 2.

As shown in fig. 9, an embodiment of the present application further provides an apparatus for expanding the capacity of a MAC address table, including:

at least one processor; and the number of the first and second groups,

a memory communicatively coupled to the at least one processor; wherein the content of the first and second substances,

the memory stores instructions executable by the at least one processor to enable the apparatus to perform:

receiving an unknown MAC message of a PC (personal computer) end through a switch, and acquiring basic information according to the unknown MAC message, wherein the basic information comprises but is not limited to a source MAC address;

adding the basic information to an address table, and judging whether the basic information is added successfully;

and if the basic information is not successfully added, calling an ACL table of the switch so as to enable the destination MAC address of the PC end to be the same as the source MAC address through the ACL table.

An embodiment of the present application further provides a non-volatile computer storage medium storing computer-executable instructions, where the computer-executable instructions are configured to:

The embodiments in the present application are described in a progressive manner, and the same and similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the device and media embodiments, the description is relatively simple, as it is substantially similar to the method embodiments, and reference may be made to some description of the method embodiments for relevant points.

The device and the medium provided by the embodiment of the application correspond to the method one to one, so the device and the medium also have the similar beneficial technical effects as the corresponding method, and the beneficial technical effects of the method are explained in detail above, so the beneficial technical effects of the device and the medium are not repeated herein.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and so forth) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

In a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include forms of volatile memory in a computer readable medium, random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium.

Computer-readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, a computer readable medium does not include a transitory computer readable medium such as a modulated data signal and a carrier wave.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising a," "8230," "8230," or "comprising" does not exclude the presence of other like elements in a process, method, article, or apparatus comprising the element.

The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art to which the present application pertains. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for expanding the capacity of a MAC address table, comprising:

2. The method of claim 1, wherein the ACL table comprises a plurality of ACL table entries, wherein the ACL table entries comprise a first matching entry and a second matching entry;

calling an ACL table of the switch, specifically comprising:

determining the first matching item, wherein the first matching item includes but is not limited to the source MAC address, setting the action of the first matching item to cancel an upper CPU, and determining Stats statistic corresponding to the ACL table entry;

and determining the second matching item, wherein the second matching item comprises but is not limited to the destination MAC address, and setting the action of the second matching item as redirection so that the destination MAC address of the PC end is the same as the source MAC address.

3. The method of claim 2, further comprising:

determining a state matching item in the second matching item through the ACL table so as to search whether the destination MAC address is included in an MAC table of the switch through the state matching item;

if the MAC table comprises the destination MAC address, the switch is enabled to hit the destination MAC address in the MAC table, and the ACL table item corresponding to the destination MAC address is deleted.

4. The method of claim 1, wherein after invoking the ACL table of the switch, the method further comprises:

receiving a first access message of the PC terminal through the switch, acquiring a first destination MAC address according to the first access message, and hitting the first destination MAC address in the ACL table through the switch so as to forward the first access message according to the first destination MAC address;

receiving a second access message for accessing the PC terminal through the switch, acquiring the destination MAC address according to the second access message, hitting the destination MAC address in the ACL table through the switch to redirect to a port of the PC terminal, and forwarding the second access message to the PC terminal.

5. The method of claim 1, further comprising:

determining a preset aging rule, and traversing the ACL table at regular time according to the aging rule;

acquiring a real-time Stats statistical value and a historical Stats statistical value of an ACL table entry in the ACL table, and comparing the real-time Stats statistical value with the historical Stats statistical value;

if the real-time Stats statistic value is different from the historical Stats statistic value, storing the real-time Stats statistic value;

and if the real-time Stats statistic is the same as the historical Stats statistic, deleting the ACL table entry.

6. The method according to claim 5, wherein deleting the ACL entry specifically includes:

determining the ACL table entry to be deleted, and deleting a first matching item, a second matching item and Stats resources corresponding to the ACL table entry.

7. The method of claim 2, further comprising:

receiving a drift message of a rear PC (personal computer) end through the switch, and acquiring basic information of the rear PC end according to the drift message;

determining the corresponding ACL table item according to the source MAC address, and deleting the ACL table item;

and establishing a new ACL list item according to the basic information of the rear PC terminal.

8. The method according to claim 1, wherein obtaining the basic information of the unknown MAC according to the packet specifically includes:

configuring a drifting action according to the source MAC address, and sending the message to a CPU according to the drifting action;

and analyzing the message through the CPU to obtain the basic information of the unknown MAC.

9. An apparatus for expanding the capacity of a MAC address table, comprising:

at least one processor; and the number of the first and second groups,

10. A non-transitory computer storage medium storing computer-executable instructions, the computer-executable instructions configured to: