CN105791125B

CN105791125B - Method and device for writing data in ternary content addressable memory

Info

Publication number: CN105791125B
Application number: CN201410830506.5A
Authority: CN
Inventors: 姜海明; 杨远田
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2014-12-26
Filing date: 2014-12-26
Publication date: 2020-03-17
Anticipated expiration: 2034-12-26
Also published as: WO2016101551A1; CN105791125A

Abstract

The invention provides a method and a device for writing data in a ternary content addressable memory. The method comprises the following steps: acquiring a link state of a physical bus between a network processor NP and a TCAM; if the link state of the physical bus is good, controlling the working mode of the write operation to be a first working mode, wherein the first working mode is not waiting for the query response of the TCAM, or not analyzing and processing the query response of the TCAM after obtaining the query response of the TCAM; when the operation of writing data into the TCAM is detected, if the working mode is the first working mode, the data is directly written into the TCAM.

Description

Method and device for writing data in ternary content addressable memory

Technical Field

The invention relates to the field of computers, in particular to a method and a device for writing data in a ternary content addressable memory.

Background

The development speed of the network is remarkable nowadays, and the increase of network traffic and the emergence of new services require network equipment with wire speed and flexible processing capability. Currently, Network chips include two major types, namely, ASIC (Application Specific integrated circuits) and NP (Network Processor). Network processors have become an effective solution for data processing in today's networks by virtue of their high speed processing and flexible programmability.

The network processor has various memories, such as SRAM, TCAM, SDRAM, etc., which store various service table entries, such as port table, MAC table, routing table, etc.

Tcam (ternary content addressable memory) is a ternary content addressable memory, and is mainly used for quickly searching an Access Control List (ACL), a route, and other entries. The TCAM is mainly characterized by fast parallel search, and is generally applied to a network processor, wherein microcode extracts relevant information from a message to form a KEY (KEY value), a search command is sent to the TCAM through a TCAM controller of an NP, and the message is processed according to a result.

FIG. 1 is a diagram of a prior art network processor connected to a TCAM. The CPU accesses the external TCAM through a TCAM adaptation interface of the NP, and the NP and the TCAM are interconnected through an Interlaken bus.

The Interlaken physical bus is composed of a plurality of lanes, and when a certain lane is aged or the link quality is poor in the operation process of the equipment, errors such as Cyclic Redundancy Check (CRC) or Framing and the like can occur in a TCAM write table. Therefore, the control plane accesses the TCAM, whether reading or writing, waits for each reading and writing, waits for the corresponding return of the TCAM and analyzes, and performs failure rewriting if an error exists.

If occasional synchronization errors or CRC occur during the operation of the Interlaken link, the TCAM can be successfully written by repeated rewriting.

At present, network services applying TCAM are many, such as IPV4/IPV6 route lookup, ACL, flow mirroring, flow statistics and the like. These services often write tables in batches, which may include tens of thousands of rules at most, and if each rule is written into the TCAM, waiting for the TCAM to return and analyzing the result is inevitably wasted for a long time, so that a long time is required for issuing a large-capacity ACL configuration at present, and the service becomes slow to take effect, so how to increase the write operation speed of the TCAM is an urgent technical problem to be solved.

Disclosure of Invention

The invention provides a method and a device for writing data in a ternary content addressable memory, which aims to solve the technical problem of how to improve the writing operation speed of a TCAM.

In order to solve the technical problems, the invention provides the following technical scheme:

a method of writing data in a ternary content addressable memory, TCAM, comprising: acquiring a link state of a physical bus between a network processor NP and a TCAM; if the link state of the physical bus is good, controlling the working mode of the write operation to be a first working mode, wherein the first working mode is not waiting for the query response of the TCAM, or not analyzing and processing the query response of the TCAM after obtaining the query response of the TCAM; when the operation of writing data into the TCAM is detected, if the working mode is the first working mode, the data is directly written into the TCAM.

After the operation mode for controlling the writing operation is the first operation mode, the method further comprises the following steps: if the link of the physical bus has an error, controlling the working mode of the write operation to be switched from a first working mode to a second working mode, wherein the second working mode is to wait for the query response of the TCAM, and after the query response of the TCAM is obtained, analyzing the query response of the TCAM; when the operation of writing data to the TCAM is detected, if the working mode is the second working mode, acquiring the query response of the TCAM, acquiring the error reason according to the query response of the TCAM, and managing the writing operation of the data according to the error reason.

Wherein the managing the write operation of the data according to the error cause includes: and if the error source is CRC, rewriting the data until the data is correctly written.

The acquiring the link state of the physical bus between the network processor NP and the TCAM includes: and reading information recorded by an error state register and a link error counting register inside the TCAM, and acquiring the link state of a physical bus between the NP and the TCAM.

The information recorded by an error state register and a link error counting register in the TCAM is read through a Management Data Input and Output (MDIO) interface, and the link state of a physical bus between the NP and the TCAM is acquired.

An apparatus for writing data in a Ternary Content Addressable Memory (TCAM), comprising: the network processor comprises an acquisition module, a processing module and a processing module, wherein the acquisition module is used for acquiring the link state of a physical bus between the NP and the TCAM of the network processor; the control module is configured to control a working mode of the write operation to be a first working mode if the link state of the physical bus is good, where the first working mode is not waiting for a query response of the TCAM, or, after the query response of the TCAM is obtained, not performing analysis and processing on the query response of the TCAM; the first write operation module is configured to, when an operation of writing data to the TCAM is detected, directly write the data into the TCAM if the operating mode is the first operating mode.

The control module is further configured to control the working mode of the write operation to switch from a first working mode to a second working mode if the link of the physical bus has an error, where the second working mode is to wait for the query response of the TCAM, and perform analysis of the query response of the TCAM after the query response of the TCAM is obtained; and the second write operation module is used for acquiring the query response of the TCAM when the operation of writing data into the TCAM is detected and if the working mode is the second working mode, acquiring the error reason according to the query response of the TCAM and managing the write operation of the data according to the error reason.

Wherein the second write operation module comprises: and the rewriting unit is used for rewriting the data until the data is written correctly if the error source is CRC.

Wherein the obtaining module is specifically configured to: and reading information recorded by an error state register and a link error counting register inside the TCAM, and acquiring the link state of a physical bus between the NP and the TCAM.

The obtaining module reads information recorded by an error state register and a link error counting register inside the TCAM through a Management Data Input and Output (MDIO) interface, and obtains the link state of a physical bus between the NP and the TCAM.

The embodiment of the invention obtains the link state between the TCAM and the NP, and controls the write operation without waiting for the return result of the TCAM and analyzing the return result when the link state is good, so that a lot of time can be saved under the condition of high-capacity write expression, the time required by completing the write operation is shortened, and the write operation speed of the TCAM is improved.

Drawings

FIG. 1 is a schematic diagram of a prior art network processor connected to a TCAM;

FIG. 2 is a flow chart illustrating a method for writing data in a ternary content addressable memory according to the present invention;

FIG. 3 is a schematic diagram of a network processor connected to a TCAM provided in the present invention;

FIG. 4 is a schematic structural diagram of an apparatus for writing data in a tri-state content addressable memory according to the present invention;

fig. 5 is another schematic structural diagram of the device shown in fig. 4.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.

Fig. 2 is a schematic flow chart of a method for writing data in a tri-state content addressable memory according to the present invention. The method shown in fig. 2 comprises:

step 201, acquiring a link state of a physical bus between a network processor NP and a TCAM;

step 202, if the link state of the physical bus is good, controlling a working mode of the write operation to be a first working mode, wherein the first working mode is not waiting for a query response of the TCAM, or after the query response of the TCAM is obtained, not analyzing and processing the query response of the TCAM;

step 203, when detecting the operation of writing data to the TCAM, if the operating mode is the first operating mode, directly writing the data into the TCAM.

The following examples of the method provided by the present invention are further illustrated:

after the operation mode for controlling the writing operation is the first operation mode, the method further comprises the following steps:

if the link of the physical bus has an error, controlling the working mode of the write operation to be switched from a first working mode to a second working mode, wherein the second working mode is to wait for the query response of the TCAM, and after the query response of the TCAM is obtained, analyzing the query response of the TCAM;

when the operation of writing data to the TCAM is detected, if the working mode is the second working mode, acquiring the query response of the TCAM, acquiring the error reason according to the query response of the TCAM, and managing the writing operation of the data according to the error reason.

Wherein the managing the write operation of the data according to the error cause includes:

and if the error source is CRC, rewriting the data until the data is correctly written.

Taking the Netlogic series TCAM widely used in the industry at present as an example, in the TCAM return result Packet Error Response format, an Error Code containing 64 bits is needed to be analyzed in the TCAM return Response result for the write operation of the TCAM. If a link CRC is found, then corresponding action is taken, such as a failed rewrite or the like.

It should be noted that, when the operating mode is the second operating mode, the write operation of the TCAM may be performed according to the existing flow, so as to ensure correct writing of data.

By controlling the write operation of the TCAM to be in different working modes, the write-in speed of the data is improved on the premise of ensuring the correct data write-in.

The method comprises the steps that the link state of a physical bus between a Network Processor (NP) and a Traffic Collision Avoidance Memory (TCAM) is obtained; and reading information recorded by an error state register and a link error counting register inside the TCAM, and acquiring the link state of a physical bus between the NP and the TCAM.

For example, the PCS layer of the Netlogic TCAM chip stores error status and error counts. The NL11K chip Commonstatus Register has the capability of detecting errors such as CRC, and the RX PCS Counter Register has CRC error count.

The characteristic that a register in a TCAM chip stores link information is utilized, on the premise of not increasing hardware cost, the information stored in the register is read by utilizing the improvement of a software program and is used as a basis for switching write operation, and the method is simple to realize.

Of course, in practical applications, the register may be set to store the bus state between the TCAM and the NP as a basis for switching the operation mode.

In order to further save hardware cost, the invention provides that information recorded by an error state register and a link error count register inside the TCAM is read through a management data Input/Output (MDIO) interface, and the link state of a physical bus between the NP and the TCAM is acquired.

FIG. 3 is a schematic diagram of a network processor connected to a TCAM according to the present invention. In the schematic diagram shown in fig. 3, an internal CPU interface in the NP is connected to the TCAM through an external MDIO interface, so as to achieve the purpose of reading information in a register in the TCAM. If the reading result shows that the error status register and the link error counting register have link errors such as CRC, the problem of the link between the NP and the TCAM is sensed in time,

and reading a register inside the TCAM at fixed time through the MDIO interface, thereby sensing the Interlaken link state between the NP and the TCAM. The advantage of borrowing the MDIO interface is that the MDIO signal line is out-of-band resource, therefore does not occupy the Interlaken bandwidth resource between NP and TCAM.

The following is a description of an application example:

two TCAM table writing modes are preset:

the first mode is as follows: and writing a table by the TCAM without waiting for response of the TCAM and analyzing and judging a response result of the TCAM according to a response format specified by a TCAM manual. This mode works in the case that the link between the NP and TCAM is in good condition.

And a second mode: and writing the table by the TCAM, wherein the TCAM needs to wait for response of the TCAM, the response result of the TCAM is analyzed and judged according to a response format specified by a TCAM manual, and if errors such as CRC exist, the TCAM needs to be rewritten in failure until the TCAM is written successfully. This mode operates in situations where the link state between the NP and TCAM is not good.

The switching between mode one and mode two is controlled by a software global variable.

After the chip is initialized, a software thread is started, and an error state register and an error count register related to a link error (such as CRC) in the TCAM are continuously scanned through the MDIO interface.

Step A01, judging whether an error is detected;

which mode of operation is used is determined by the software thread scan results, i.e., global variable values. If the software thread scans the register and finds that link errors such as CRC exist, the step A02 is carried out; otherwise, go to step a 03.

Step A02, writing a table in a mode I;

in the mode, the TCAM return result does not need to be waited, the return result does not need to be analyzed, and the failure rewriting is carried out, and the mode is a normal quick table writing mode

Step A03, writing a table in a mode II;

the mode needs to wait for TCAM return result, analyze the return result, if there is link problem such as CRC, then carry out failure rewriting until correct writing

The application example discloses a fast table writing mode aiming at the problem that the batch write of TCAM is slow to take effect at present. And reading an error state register and an error counter related to the link quality inside the TCAM through an MDIO out-of-band interface of the TCAM, thereby determining which working mode is adopted. Under the normal condition of TCAM link quality, the TCAM return result does not need to be waited, and the return result does not need to be analyzed, so that much time can be saved under the condition of high-capacity expression, and the service validation time is shortened.

Fig. 4 is a schematic structural diagram of an apparatus for writing data in a tri-state content addressable memory according to the present invention. The schematic shown in fig. 4 includes:

an obtaining module 401, configured to obtain a link state of a physical bus between a network processor NP and a TCAM;

a control module 402, configured to control a working mode of the write operation to be a first working mode if a link state of the physical bus is good, where the first working mode is not waiting for a query response of the TCAM, or after the query response of the TCAM is obtained, not performing analysis and processing on the query response of the TCAM;

a first write operation module 403, configured to, when an operation of writing data to the TCAM is detected, if the operating mode is the first operating mode, directly write the data into the TCAM.

Fig. 5 is another schematic structural diagram of the device shown in fig. 4. The apparatus shown in the schematic diagram of fig. 5 comprises:

the control module 402 is further configured to control the working mode of the write operation to switch from a first working mode to a second working mode if the link of the physical bus has an error, where the second working mode is to wait for the query response of the TCAM, and perform analysis on the query response of the TCAM after the query response of the TCAM is obtained;

a second write operation module 404, configured to, when an operation of writing data to the TCAM is detected, obtain a query response of the TCAM if the working mode is the second working mode, obtain an error reason according to the query response of the TCAM, and manage the write operation of the data according to the error reason.

Wherein the second write operation module 404 includes:

and the rewriting unit is used for rewriting the data until the data is written correctly if the error source is CRC.

The obtaining module 401 is specifically configured to:

and reading information recorded by an error state register and a link error counting register inside the TCAM, and acquiring the link state of a physical bus between the NP and the TCAM.

The obtaining module 401 reads information recorded by an error status register and a link error count register inside the TCAM through the management data input/output MDIO interface, and obtains a link status of a physical bus between the NP and the TCAM.

It will be understood by those of ordinary skill in the art that all or part of the steps of the above embodiments may be implemented using a computer program flow, which may be stored in a computer readable storage medium and executed on a corresponding hardware platform (e.g., system, apparatus, device, etc.), and when executed, includes one or a combination of the steps of the method embodiments.

Alternatively, all or part of the steps of the above embodiments may be implemented by using an integrated circuit, and the steps may be respectively manufactured as an integrated circuit module, or a plurality of the blocks or steps may be manufactured as a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

The devices/functional modules/functional units in the above embodiments may be implemented by general-purpose computing devices, and they may be centralized on a single computing device or distributed on a network formed by a plurality of computing devices.

Each device/function module/function unit in the above embodiments may be implemented in the form of a software function module and may be stored in a computer-readable storage medium when being sold or used as a separate product. The computer readable storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for writing data in a Ternary Content Addressable Memory (TCAM), comprising:

acquiring a link state of a physical bus between a network processor NP and a TCAM;

if the link state of the physical bus is good, controlling the working mode of the write operation to be a first working mode, wherein the first working mode is not waiting for the query response of the TCAM, or not analyzing and processing the query response of the TCAM after obtaining the query response of the TCAM;

when the operation of writing data into the TCAM is detected, if the working mode is the first working mode, the data is directly written into the TCAM.

2. The method of claim 1, wherein after controlling the operating mode of the write operation to be the first operating mode, further comprising:

3. The method of claim 2, wherein managing the writing of the data according to the error cause comprises:

4. The method of claim 1, wherein obtaining the link state of the physical bus between the network processor NP and the TCAM comprises:

5. The method of claim 4, wherein the information recorded by the error status register and the link error count register inside the TCAM is read by the Management Data Input Output (MDIO) interface to obtain the link status of the physical bus between the NP and the TCAM.

6. An apparatus for writing data in a Ternary Content Addressable Memory (TCAM), comprising:

the network processor comprises an acquisition module, a processing module and a processing module, wherein the acquisition module is used for acquiring the link state of a physical bus between the NP and the TCAM of the network processor;

the control module is configured to control a working mode of the write operation to be a first working mode if the link state of the physical bus is good, where the first working mode is not waiting for a query response of the TCAM, or, after the query response of the TCAM is obtained, not performing analysis and processing on the query response of the TCAM;

the first write operation module is configured to, when an operation of writing data to the TCAM is detected, directly write the data into the TCAM if the operating mode is the first operating mode.

7. The apparatus of claim 6, further comprising a second write module;

the control module is further configured to control the working mode of the write operation to switch from a first working mode to a second working mode if the link of the physical bus has an error, where the second working mode is to wait for a query response of the TCAM, and perform analysis of the query response of the TCAM after the query response of the TCAM is obtained;

and the second write operation module is configured to, when an operation of writing data to the TCAM is detected, obtain a query response of the TCAM if the working mode is the second working mode, obtain an error reason according to the query response of the TCAM, and manage the write operation of the data according to the error reason.

8. The apparatus of claim 7, wherein the second write module comprises:

9. The apparatus of claim 6, wherein the obtaining module is specifically configured to:

10. The apparatus of claim 9, wherein the obtaining module obtains the link status of the physical bus between the NP and the TCAM by reading information recorded in an error status register and a link error count register inside the TCAM through an MDIO interface.