JP4079764B2 - Router device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a router apparatus that performs packet transfer processing in a network such as a LAN. The present invention is used in a router apparatus that performs a filtering process together with a routing process in packet transfer.
[0002]
[Prior art]
In general, a small router with a small number of accommodating ports performs packet transfer by CPU software processing in order to increase the price-performance ratio.
[0003]
A router apparatus that performs packet transfer by conventional software processing will be described with reference to FIG. In FIG. 11, a LAN communication controller A 1101 transfers transmission / reception data between a memory 1108 as a main memory of the router device and a LAN port 1107. Note that the LAN communication controller B 1115 performs the same operation as the LAN communication controller A 1101 for the LAN port B 1116 with the same configuration as the LAN communication controller A 1101.
[0004]
The memory 1108 stores a router operation program 1111 of the CPU 1109, router operation parameters 1112 including a routing table and a filtering list, and communication data transmission / reception buffers 1113 and 1114 to be transmitted / received to / from each LAN communication controller 1101 and 1115.
[0005]
The CPU 1109 executes the router operation program 1111 stored in the memory 1108. The router operation program 1111 causes the CPU 1109 to perform the following operations. As a process during startup after power-on, the LAN communication controller operation parameter (self MAC address) is written to the memory of each LAN communication controller. After startup, filtering processing (discarding packets that match the filtering list) and routing according to the parameter The IP packet is transferred by the operation (determination of the transfer destination LAN port by searching the routing table of the destination IP address of the received IP packet).
[0006]
The LAN communication controller 1101 includes a dedicated processor 1102, a ROM 1103, a memory bus interface 1105, and a LAN interface 1106, and transfers transmission / reception communication data between the LAN port A 1107 and the memory 1108.
[0007]
The dedicated processor 1102 reads and executes the microcode program 1110 stored in the ROM 1103.
[0008]
The ROM 1103 stores a microcode program 1110. The microcode program 1110 is a program for operating the dedicated processor 1102 to transmit and receive communication data between the transmission / reception buffer 1113 in the memory 1108 and the LAN interface 1106 using a general LAN communication controller.
[0009]
Next, the operation of this conventional apparatus will be described with reference to the flowchart shown in FIG. 12, taking as an example the packet transfer from LAN port A to LAN port B.
[0010]
When communication data arrives at the LAN port A, the dedicated processor 1102 in the LAN communication controller A 1101 starts receiving operation according to the microcode program 1110 in the ROM 1103. First, the MAC address (= on LAN) included in the frame on the LAN The physical MAC address of each LAN port) is a broadcast address (address to all LAN ports existing on the LAN) or the router operation parameter 1112 stored in the memory 1108. (1201), and if it does not match any of the frames, the frame is not addressed to the own device, so it is canceled without receiving any more. (1202). If it matches any of the frames, it is determined that the frame is addressed to its own device, and the reception is continued. The reception data of the frame is sequentially transferred to the reception buffer 1113 of the memory 1108 until the reception is completed (1203). After transfer is completed, the process returns to reception waiting.
[0011]
Next, the CPU 1109 checks whether communication data has arrived in the reception buffer (1204). If there is reception data, the CPU 1109 moves to filtering processing, compares with the filtering list in the memory 1108, and discards it. It is determined whether to perform the transfer process (1205). Next, in the transfer process, the routing table in the memory 1108 is searched to determine the transfer destination LAN port (LAN port B in this example). Subsequently, the reception data is transferred to the transmission buffer 1114 of the port, and the data is actually transmitted from the LAN port B 1116 by issuing a transmission instruction to the operation parameter of the LAN communication controller of the port. Note that the routing table search operation is well known to those skilled in the art, and detailed operation thereof is omitted.
[0012]
However, a router device that performs packet transfer by conventional software processing has the following problems.
[0013]
The first problem is that both the filtering process and the routing process are performed by the CPU, so that the filtering capability is not necessary and the transfer capability as a device when the filtering process is performed as compared with the case where only the routing process is performed. Is significantly reduced.
[0014]
The second problem is that both the filtering process and the routing process are performed by the CPU. Therefore, when the transfer capability is increased when both the filtering process and the routing process are performed, the CPU performance is increased or the filtering process is performed. This means that there is a large cost such as preparing another CPU for exclusive use.
[0015]
Therefore, a proposal has been made to perform filtering processing on the LAN communication controller side in order to reduce the filtering processing load on the CPU, and to share the processing so that the CPU performs routing processing (Patent Document 1).
[0016]
In the configuration described in Patent Document 1, a filtering control unit is provided on the LAN communication controller side in order to increase the processing efficiency of the CPU, and a filtering process is performed to discard packets that are not received in comparison with a received packet and a filtering list. The CPU performs a routing process or a bridge process on the packet subjected to the filtering process.
[0017]
[Patent Document 1]
JP 7-336384 A
[0018]
[Problems to be solved by the invention]
However, in Patent Document 1, the filtering control unit provided in each LAN communication controller is a packet to be discarded by comparing the MAC address extracted from the received packet (frame) with the address set in the CAM. In such a case, the disposal is instructed. In the filtering process in this filtering control unit, the setting of the CAM address can be changed, but the filtering operation itself is a fixed process, and the filtering process can be dynamically changed according to the traffic situation or VLAN. Like (Virtual Local Area Network), processing corresponding to processing in which a plurality of virtual channels are input to and output from the same port cannot be performed flexibly.
[0019]
The present invention is based on the above-described problems, and an object thereof is to provide a router device that can reduce the load on the main CPU of the router and can dynamically change the filtering process performed by each LAN communication controller. Further, in the present invention, in a form in which the same port is used in a plurality of VLANs, the LAN communication controller side determines which VLAN packet is used, and reduces the routing processing load on the main CPU to use the VLAN. An object of the present invention is to provide a router device that does not lower the cost performance of the router.
[0020]
Means to be Solved by the Invention
In the present invention, the main processor of the router apparatus mainly performs routing processing, and a dedicated processor (LAN communication processor) provided in the LAN communication controller performs transmission / reception processing with the LAN and performs filtering processing. The processor and the packet transfer process are shared.
[0021]
Each LAN communication controller is provided with rewritable memory means for storing a microcode program as a processing program executed by the dedicated processor, and the dedicated processor performs the process by the microcode program stored in the memory means. Since the memory means is rewritable, the microcode program executed by the dedicated processor is dynamically rewritten according to the status of the router device. That is, the microcode executed by the dedicated processor is programmable. For this reason, for example, in the filtering process, the load on the main processor changes according to the traffic situation of the network. Therefore, the microcode program stored in the rewritable memory can be discarded according to the load on the main processor. By changing to a microcode program in which priority is set to and executing it, a filtering process according to the traffic situation can be executed. In the case of a VLAN that handles a single LAN port as if multiple channels are connected, the dedicated processor of the LAN communication controller determines which VLAN packet it is and transfers it to the transfer destination reception buffer.
[0022]
That is, the present invention comprises a main processor that performs packet routing processing, a main memory that stores packets for routing processing programs and transfer processing, and a LAN communication controller that is connected to a network and performs transmission / reception processing for packets transmitted and received. The LAN communication controller includes a LAN interface unit that performs transmission / reception processing of packets with the LAN, a bus interface unit that performs interface processing with a bus to which the main processor and the main memory are connected, and the LAN communication controller. In the router apparatus provided with a processor dedicated to LAN communication that performs packet transmission / reception processing and filtering processing performed by the LAN, the LAN communication controller can rewrite a processing program executed by the LAN communication dedicated processor. Characterized by comprising a memory means capable of rewriting to be stored.
[0023]
Here, the processing program stored in the memory means includes a plurality of filtering lists in which priorities are set according to the load of the main processor that performs routing processing, and the processor dedicated to LAN communication includes the load of the main processor And a means for executing a filtering process based on a filtering list in which a priority selected in accordance with is set. The processing program stored in the memory means identifies a tag attached to a packet for each VLAN when the LAN handled by one LAN communication controller is a VLAN in which a plurality of virtual channels are set. It is a program for performing packet transmission / reception processing, and the processor dedicated to LAN communication can include means for identifying a tag for each VLAN and executing packet transmission / reception processing.
[0024]
The memory means is divided into an area used as a transmission / reception buffer for storing a packet for transmission / reception processing, an area for storing a processing program executed by the dedicated processor, and an area for storing a communication processing operation parameter. Can be used.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0026]
FIG. 1 is a diagram showing a configuration of a router apparatus showing an example of an embodiment of the present invention, FIG. 2 is a diagram showing an example of use of a RAM 104 in the LAN communication controller of FIG. 1, and FIG. 3 is a LAN communication controller FIG. 4 is a flowchart illustrating packet transfer processing in this embodiment, FIG. 5 is a flowchart illustrating filtering processing in the LAN communication controller, and FIG. FIG. 7 is a flowchart illustrating an example of a filtering list (table). FIG.
[0027]
Referring to FIG. 1, there is shown a router device 100 that performs packet transfer by software processing as one embodiment of the present invention.
[0028]
In FIG. 1, a router device 100 is provided with a CPU 109 that mainly serves as a main processor of a router device that performs routing processing, a memory 108 that the CPU 109 uses for packet routing processing, and a LAN port, respectively, and transmission / reception control of packets with the LAN. A plurality of LAN communication controllers A 1101, LAN communication controllers B... Connected to the CPU 109 and the memory 108 via a bus.
[0029]
The LAN communication controller 101 includes a dedicated processor 102, a ROM 103, a RAM 104, a memory bus interface 105, and a LAN interface 106. The LAN communication controller 101 transfers transmission / reception communication data between the LAN port A 107 and the memory 108 and performs a filtering process using a microcode program described later. Do.
[0030]
The RAM 104 can be rewritten from the CPU 109 and can also be read from and written to by the dedicated processor 102. As shown in FIG. 2, the operation parameter 201 as the LAN communication controller, the communication data temporary storage buffer 203, and the microcode that can be executed by the dedicated processor 102 The program 202 is stored.
[0031]
The dedicated processor 102 reads and executes the microcode program 110 stored in the ROM 103 or the microcode program 202 stored in the RAM 104.
[0032]
The ROM 103 stores a microcode program 110. The microcode program 110 operates the dedicated processor 102 to transfer communication data between the memory 108 and the LAN interface 106 as a general LAN communication controller according to the operation parameter 201 stored in the RAM 104, and This is a program for executing the microcode program 202.
[0033]
The microcode program 202 is a program that causes the dedicated processor 102 to perform comparison based on pattern matching on the transfer data transferred between the memory 108 and the LAN interface 106 and processing based on the result, that is, filtering processing.
[0034]
The LAN communication controller B115 performs the same operation on the LAN port B116 with exactly the same configuration as the LAN communication controller A101.
[0035]
The memory 108 stores a router operation program 111 and a router operation parameter 112 of the CPU 109 and communication data transmission / reception buffers 113 and 114 to be transmitted / received to / from the LAN communication controller 101 or 115.
[0036]
The CPU 109 executes the router operation program 111 stored in the memory 108. The router operation program 111 causes the CPU to perform the following operations.
[0037]
As a process during startup after power-on, the LAN communication controller operation parameters (set of the self MAC address and microcode execution flag) and microcode for performing the filter operation are written in the RAM of each LAN communication controller such as the RAM 104. The IP packet is transferred by the routing operation according to the above (determination of the transfer destination LAN port by searching the routing table of the destination IP address of the received IP packet).
[0038]
Although the configuration of the embodiment has been described in detail above, the routing search operation of the router operation software stored in the memory 108 of FIG. 1 is well known to those skilled in the art, and thus detailed description thereof is omitted.
[0039]
In the description of the router device shown in FIG. 1, a LAN communication controller is provided for each LAN port. However, two LAN ports may be processed by one LAN communication controller as shown in FIG.
[0040]
Next, the operation of the router apparatus 100 in FIG. 1 will be described using the flow chart shown in FIG. 4 by taking IP packet transfer from the LAN port A 107 to the LAN port B 116 as an example.
[0041]
In the RAM 104 of FIG. 1, a self-MAC address and a microcode execution flag are set as operation parameters, and a microcode program for performing a filtering operation described later is set in the microcode program storage area by the CPU 109 after the apparatus power is turned on. It is written in advance during the conversion operation.
[0042]
In FIG. 4, when a frame on the LAN carrying a packet to be transferred to the LAN port B 116 arrives at the LAN port A 107, the LAN communication controller A 101 performs the following operation according to the microcode program stored in the ROM 103 of FIG. The dedicated processor 102 starts.
[0043]
First, for a MAC address included in a frame on the LAN (= physical address of each LAN port on the LAN), the destination MAC address of the received frame is a broadcast address (addresses to all LAN ports existing on the LAN) ) Or the self-MAC address set in the operation parameter stored in the RAM 104 in FIG. 1 is determined (401). Since it is not addressed to the device, it is not subject to reception and no further reception is performed (402).
[0044]
If it matches any of the frames, it is determined that the frame is addressed to its own device, and the reception is continued. The received data of the frame is sequentially transferred to the communication data temporary storage buffer of the RAM 104 in FIG. 1 until the reception is completed. After completion of the transfer, since the microcode execution flag of the operation parameter stored in the RAM 104 of FIG. 1 is set, a microcode program for the filtering operation (403) described later is called and executed. As a result, when it is determined to be discarded, the data in the communication data temporary storage buffer 203 is discarded and the process returns to waiting for reception. When it is determined to be transfer processing, the data in the communication data temporary storage buffer 203 is stored in the memory 108. After transfer (404) to the reception buffer 113, the process returns to reception waiting.
[0045]
Here, the microcode program for performing the filtering operation (403) will be described using the flowchart shown in FIG. 5 and the example of the filtering list shown in FIG.
[0046]
First, the filtering list as shown in FIG. 6 is included as a part of the microcode program, and at least one header information of the IP packet that the user discards even if it is received without being subject to transfer in advance is registered. .
[0047]
The dedicated processor 102 reads the first header information in the filtering list 206 and compares it with the header of the IP packet included in the received data in the communication data temporary storage buffer (501). Return to the microcode program 110 of (502). If they do not match, it is checked whether there is the next header information in the filtering list (503). If it does not exist, it does not match all the items in the list. Return to (504). If the next header information exists, the header information is read (505), and the process returns to the comparison (501) with the header of the IP packet in the communication data temporary storage buffer. This is the description of the filtering operation (403).
[0048]
Next, the routing operation (405) by the CPU 109 after being transferred to the reception buffer of the memory 108 without being subject to the filtering list will be described. The CPU 109 operates according to the router operation program 111, and the operation of the software is as shown in the flowchart shown in FIG.
[0049]
First, the CPU 109 always checks whether communication data does not reach the reception buffer of each LAN port when there is no other processing (701), and if any reception data reaches any of the reception buffers. Move on to the next process. Next, a routing table search is performed to determine the transfer destination LAN port (LAN port B in this example) (702), the received data is transferred to the transmission buffer of that port (703), and the LAN communication controller of that port is After issuing a transmission instruction to the operation parameter (704), the process returns to the reception buffer check again. Since the routing table search operation is well known to those skilled in the art, a detailed description of the operation is omitted. Up to here, the routing operation (405) of the CPU 109 has been described.
[0050]
Subsequently, in the LAN communication controller B115 that receives the transmission instruction at 704 in FIG. 7, when there is a transmission instruction from the CPU 109 through the operation parameter in the microcode program, the communication data is sequentially read from the transmission buffer and transferred to the LAN interface. Therefore, the dedicated processor operates accordingly, the data is read from the transmission buffer 114, and the data is transmitted to the LAN port B116.
[0051]
In the configuration of the invention described above, the filtering process is performed by the LAN communication controller and the CPU can concentrate on the routing process, so that the transfer capability can be improved as compared with the case where the filtering process is also performed by the CPU. In addition, since the microcode program for performing the filtering operation by the LAN communication controller is stored in the LAN communication controller RAM, various filter functions similar to those performed by the CPU can be realized without performing the processing of the CPU. Furthermore, since a dedicated processor originally incorporated in the LAN communication controller is used instead of the CPU, the router device can be realized at low cost because it can be realized only by adding RAM to the LAN communication controller.
[0052]
(Application examples)
An example will be described in which the rewritable memory of the present invention is provided in a LAN communication controller, and an embodiment in which the microcode program necessary for processing executed by a dedicated processor is rewritten is applied.
[0053]
(First application example)
The basic configuration of the router device is the same as the configuration shown in FIG. 1, but by further devising a microcode program that compares the filtering list and received data in the LAN communication controller, The function can be demonstrated.
[0054]
The flowchart is shown in FIG. 8, and an example of the filtering list is shown in FIG. In FIG. 8, reference numeral 801 indicates that the load on the CPU 109 is high (for example, 30% or less) / medium (for example, 50% or less) / low (for example, 50% or more) from the ratio of the reception buffers of the LAN port of the memory 108 that are free. ). FIG. 9 is a filtering list in which priority is added to header information of packets to be discarded.
[0055]
Here, the definition of priority is as follows. If A has a high priority and the load is medium or low, this list is invalid and the header information is not compared. If the priority of B is medium and the load is low, this list is invalid and the header information is not compared. C has a low priority, and the list is valid regardless of the load state. For valid lists, compare header information and discard if they match. Subsequently, in the process 802, it is determined whether the list is valid by comparing the priority of the list with the load classified in 801.
[0056]
As described above, in the first application example, since the filtering operation according to the transfer priority can be performed in accordance with the load state of the CPU, only the high priority packet is received when the CPU load is high and the reception buffer is low. The effect of reducing the discard of high priority packets by transferring to the buffer, that is, realizing the input QoS can be obtained.
[0057]
(Second application example)
As another application example of the present invention, the basic configuration is the same as the configuration shown in FIG. 1, but a new function can be exhibited by further devising the microcode program of the LAN communication controller.
[0058]
In this second application example, when two VLANs are used on the same port, the determination of which VLAN the received data is is performed by the microcode program of the LAN communication controller instead of the CPU. An example of the operation will be described with reference to the flowchart shown in FIG. Checks whether the VLAN tag value is 1 or 2 for the received data transferred to the communication data temporary buffer, which is subject to reception when the MAC address is confirmed, and determines one of the two VLANs. (FIG. 1001). Subsequently, the reception frame is transferred to each VLAN reception buffer at the branch destination.
[0059]
As described above, in this application example, since the determination is made by the LAN communication controller and the data is transferred to the reception buffer for each VLAN, it is not necessary to determine which VLAN in the CPU, and compared with the case where the determination is made by the CPU. Thus, there is an effect that the routing capability as a device does not deteriorate when the VLAN is used.
[0060]
In the above description of the embodiment of the invention and the description of the application example, the RAM is used as an example for storing the buffer, the microcode program, and the operation parameter. However, the memory used as the buffer may be provided separately. . In addition, when a buffer for temporarily storing IP packets is separately provided, the RAM for storing the microcode program mainly reads the operation parameters and the filtering list from the dedicated processor, and the number of times of writing is not so large. It may be a memory composed of an EEROM, a flash memory, or the like, which may be less.
[0061]
Further, the ROM for storing the microcode program may be configured such that the processing contents executed by the LAN communication controller from the outside can be rewritten using a memory in which the microcode program can be rewritten, for example, EEROM, SRAM or the like. By rewriting the microcode program from the outside, it is possible to flexibly cope with changes in the LAN configuration, changes in processing contents, and changes in version.
[0062]
【The invention's effect】
In the present invention, the dedicated processor of the LAN communication controller can change the microcode program stored in its rewritable RAM, so that the filtering process can be performed flexibly, reducing the burden on the CPU as the main processor. And the processing capacity can be improved. In addition, by rewriting the microcode program in a programmable manner, it is possible to reduce the discard of packets with high priority according to the traffic state and realize high QoS communication. Further, even when a VLAN is used, since the LAN communication controller can determine which VLAN the packet that has been processed by the CPU so far is, the processing load on the CPU of the router is reduced. As a performance can be improved. In addition, the processing by the dedicated processor of the LAN communication controller uses the dedicated processor originally built in the LAN communication controller, so the above-mentioned functions of the LAN communication controller are realized simply by adding a rewritable memory to the LAN communication controller. Therefore, the function of the router device can be improved at a low cost.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a router device according to an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a RAM of a LAN communication controller.
FIG. 3 is a diagram showing another configuration of the LAN communication controller.
FIG. 4 is a flowchart for explaining the operation of the router device.
FIG. 5 is a flowchart for explaining a filtering operation of the LAN communication controller.
FIG. 6 is a diagram showing an example of a filtering list.
FIG. 7 is a flowchart for explaining a CPU routing operation.
FIG. 8 is a flowchart for explaining a filtering operation of the first application example.
FIG. 9 is a diagram showing an example of a filtering list of the first application example.
FIG. 10 is a flowchart for explaining the operation of the LAN communication controller of the second application example.
FIG. 11 is a diagram showing a configuration of a conventional router device.
FIG. 12 is a flowchart for explaining the operation of a conventional router device.
[Explanation of symbols]
100, 1100 router device
101 115, 1101, 1115 LAN communication controller
102, 1102 dedicated processor
103, 1103 ROM
104 RAM
105, 1105 Memory bus interface
106, 1106 LAN interface
107, 1107, 116, 1116 LAN port
108, 1108 memory
109, 1109 CPU
110 1110 Microcode
111, 1111 router operation program
112, 1112 Router operating parameters
113, 114, 1113, 1114 buffer

Claims (3)

A main processor for performing packet routing processing, a main memory for storing packets for routing processing programs and transfer processing, and a LAN communication controller for performing transmission / reception processing for packets transmitted and received connected to the network,
The LAN communication controller performs a LAN interface unit that performs packet transmission / reception processing with a LAN, a bus interface unit that performs interface processing with the bus to which the main processor and main memory are connected, and the LAN communication controller. In a router device equipped with a dedicated processor for LAN communication that performs packet transmission / reception processing and filtering processing,
The LAN communication controller includes rewritable memory means for storing a processing program executed by the processor dedicated to LAN communication in a rewritable manner,
The processing program stored in the memory means includes a plurality of filtering lists in which priorities are set according to the load of the main processor that performs routing processing, and the processor dedicated to LAN communication corresponds to the load of the main processor A router device comprising: means for performing filtering processing based on a filtering list in which a selected priority is set . The memory means is divided into an area used as a transmission / reception buffer for storing a packet for transmission / reception processing, an area for storing a processing program executed by the processor dedicated to LAN communication, and an area for storing communication processing operation parameters. The router device according to claim 1, wherein the router device is used. A main processor for performing packet routing processing, a main memory for storing packets for routing processing programs and transfer processing, and a LAN communication controller for performing transmission / reception processing for packets transmitted and received connected to the network,
The LAN communication controller performs a LAN interface unit that performs packet transmission / reception processing with a LAN, a bus interface unit that performs interface processing with the bus to which the main processor and main memory are connected, and the LAN communication controller. A dedicated processor for LAN communication that performs packet transmission / reception processing and filtering processing
In the router device,
The LAN communication controller includes rewritable memory means for storing a processing program executed by the processor dedicated to LAN communication in a rewritable manner,
The memory means is divided into an area used as a transmission / reception buffer for storing packets for transmission / reception processing, an area for storing a processing program executed by the dedicated processor, and an area for storing communication processing operation parameters. Be done
A router device characterized by that .

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