JPH09116569A - Switching hub - Google Patents

Abstract

(57) [Summary] [Problem] When there are more received frames than other ports or when only a specific port is set to a high transmission rate, there is a risk of overflow in these ports. Interface units 112 _{-1 to} 112 _-n
And two of the communication control LSIs 110 _{-1 to} 110 _-n to which the buffers 111 _{-1 to} 111 _-n are respectively connected by internal paths 105 and 106 of the switch unit 108 controlled by the switching control unit 109. However, the priority of the frame transfer processing of each of the buffers 111 _{-1 to} 111 _{-n is} the switching hub that performs simultaneous communication through a plurality of routes, and the priority setting unit 121 sets the priority of the network management software 12.
4 is set based on this result, and a plurality of frames are continuously transferred from the port set as the highest priority based on this result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching hub for simultaneously communicating between a plurality of terminal devices.

[0002]

2. Description of the Related Art In recent years, switching hubs have attracted attention. The switching hub has a feature that communication between a plurality of ports can be simultaneously performed while maintaining a port speed of 10 Mbit / sec, for example. FIG. 7 is an explanatory diagram showing the operating principle of the switching hub.

The switching hub 101 comprises a plurality of input / output ports 104, 105, 106, 107 and a switch section 108 for connecting the input port and the output port. Simultaneous communication is possible. In the case of FIG. 7, between port 102 and port 106, between port 103 and port 105, port 1
04 and the port 107 can be simultaneously communicated with each other.

FIG. 8 is a block diagram showing the structure of a conventional switching hub. The switching hub 101 includes, in addition to the switch unit 108, a switching control unit 109 that controls the switch unit 108 and communication control LSIs 110 _-1 , 110 _-2 , ... 110 connected to the switch unit 108.
_{- (n-1), 110} -n, the communication control LSI 110 _-1 to 11
Buffers 111 _-1 , 111 _-2 connected to each of 0 _-n ,
... 111- _(n-1) , 111 _-n , communication control LSI 110
_{-1 to} 110 _-n, the interface (I
/ F) section 112 _-1 , 112 _-2 , ... 112- _(n-1) , 1
12- _n . Further, the interface units 112 _-1 , 112 _-2 , ... 112- _(n-1) ,
Each of the 112 _-n has a transmission line 113 _-1 , 113 _-2 , ...
Terminal device 11 via each of _{113- (n-1)} and 113 _-n
Each of 4 _-1 , 114 _-2 , ... 114- _(n-1) , 114 _-n is connected.

FIG. 9 is an explanatory diagram showing the connection operation of the switching hub having the configuration shown in FIG. 8. When internal paths 115 and 116 are formed in the switch section 108, the internal path 11 is shown.
5, the terminal device 114 _-1 and the terminal device 114- _(n-1) are connected to each other, and the terminal device 114 _-2 and the terminal device 114 _-n are connected to each other via the internal path 116, and simultaneous communication can be performed in each system. it can.

[0006] Next, with reference to FIG. 10 will be described the communication between the communication control LSI 110 _-1 to 110 _-n and the switching control unit 109. Here, the communication control LSI 110
_A case where frame transfer is performed from _-1 to the port of the communication control LSI 110 _-n will be described. First, communication control L
Upon receiving the frame from the terminal device 114 _{-1, the} SI 110 _-1 stores the frame in the buffer 111 _-1 and sends the transfer request signal 117 to the switching control unit 109.
The switching control unit 10 that has received the transfer request signal 117
9 determines the destination, switches the switch unit 108 to set the internal path 119, and sends the transfer permission signal 118 to the communication control LSI 110 _-1 . The communication control LSI 110 _{-1 which} has received the transfer permission signal 118 reads the frame from the buffer 111 _-1 and transmits it to the internal path 119.

FIG. 11 is a flow chart showing a data transfer process in the connection state shown in FIG. First, the communication control LSI 110 _-1 to 110 _-n receives data from the terminal device 114 _-1 to 114 _-n are connected (step 201). Next, the communication control LSIs 110 _{-1 to} 110 _-n
Sends a transfer request signal 11 to the switching control unit 109.
7 is transmitted (step 202). After that, the switching control unit 109 determines the destination (step 20).
3) Then, the switch unit 108 is caused to switch the route based on the determination result (step 204). Further, the switching control unit 109 is a communication control LSI that has issued a transfer request.
The transfer permission signal 118 is sent to 110 _{-1 to} 110 _-n (step 205). The transfer permission signal 118 communication control LSI 110 _-1 to 110 _-n for receiving the starts transferring the data to the internal path connected (S20
6).

FIG. 12 is a flow chart showing details of the processing performed by the switching control unit 109. First, starting with port number X = 1 (step 301), it is then determined whether or not the relationship of X ≧ N (N is the maximum port number) is satisfied (step 302). If the determination result is X <N, X = 1 is set (step 303) and the determination of X ≧ N is performed again. When X ≧ N is determined, it is determined whether a transfer request is issued from the communication control LSI with the port number X (step 304). When the transfer request is not issued from the communication control LSI of the port number X, the port number X is set to X = X + 1 (step 305), and the process is performed in step 3
Return to 02.

When a transfer request is issued from the communication control LSI having the port number X, the switching control unit 109 determines the destination (step 306) and the switch unit 10
8 is instructed to switch the route. The switch unit 108 executes path switching based on this command (step 30).
7). Further, the switching control unit 109 issues a transfer permission signal to the communication control LSI having the port number X (step 308), and further sets the port number X to X = X + 1 (step 309).

In this way, the switching control unit 109 is
It is determined whether or not there is a transfer request from the communication control LSI for each port in the repeating order from the port number 1 to the maximum port number N. If there is a transfer request, the destination is determined,
The process of switching the path of the switch unit and issuing the transfer permission is performed only once, and the process proceeds to the next port. FIG. 13 is an explanatory diagram showing the state in the reception buffer of each port and the order in which the transfer process is performed.

In the figure, 120 _-1a , 120 _-1b ... 12
0- _{(n-1) a} , _{120- (n-1) b} , 120 _-na , 120 _-nb
Is a received frame stored in each of the buffers 111 _{-1 to} 111 _-n , and processing for transferring frames one by one in a repeating order from port number 1 to the maximum port number is performed. Be seen. That is, as shown in FIG. 13, the received frames 120 _-1a , 120 _-2a , _...
..120- _{(n-1) a} , 120 _-na , 120 _-1b , 120
_-2b ... are transferred in this order.

[0012]

However, according to the conventional switching hub, the transfer processing of each port has the same priority, and one frame per port is sequentially repeated from the port number 1 to the maximum port number. Transfer processing is performed one by one. For this reason, as shown in FIG. 14, only port m has more received frames than other ports (for example, while another port has two received frames, 120
_{-ma to} 120- _mh ), communication concentrates on the port m and the buffer of the port m may overflow.

Further, only a certain specific port is 100 Mb
/ S transmission rate, other ports are 10Mb / s
If the frame size is the same, the port with 100 Mb / s transmission rate will receive the frame 10 times faster than other ports. Overflow as shown in FIG. 14 may occur.

Further, consider a case where the switching control unit 109 can process only one request at the same time for transfer requests from a plurality of communication control LSIs. Normally, since each port has the same priority, as shown in FIG. 15, when there is an unprocessed received frame in each of ports 1 to 4, port 1 → port 2 → port 3 → port 4 → port Processing is performed in the order of 1. However, when only the buffer 111 _{-1 of the} port 1 holds a large number of unprocessed received frames, the processes of the ports 2 to 4 intervene in the process of the port, so that the reception of the port 1 is concentrated, Overflow may occur in the buffer 111 _-1 .

Therefore, an object of the present invention is to provide a switching hub which prevents a buffer from overflowing even when received frames are concentrated on a specific port. Another object of the present invention is to provide a switching hub that prevents other ports from overflowing the buffer even when the transmission speed of a specific port is set to a high speed.

[0016]

In order to achieve the above object, the present invention relates to a plurality of interface units to which a plurality of ports are connected, a plurality of communication control units to which the interface units are connected, and A switching hub including a buffer provided for each communication control unit to store information, a switch unit connecting the communication control units to form a plurality of routes, and a switching control unit determining a route in the switch unit In the above, in the priority setting section for setting the priority of the information transfer processing in the plurality of ports based on the network management software, the plurality of information is continuously transferred from the port set as the highest priority in the priority setting section. A control means is provided.

According to this structure, the priority setting unit
It is decided which port should be given priority to operate,
The port that stores a large amount of information (specifically, a frame) is operated so as to transfer more data to other ports. Therefore, a specific port never overflows. Further, the above object is to provide a plurality of interface units to which a plurality of ports are connected, a plurality of communication control units to which the interface units are connected, a buffer provided for each communication control unit to store information, In a switching hub that includes a switch unit that connects the communication control unit to form a plurality of routes and a switching control unit that determines the route in the switch unit, a buffer storage amount that monitors the storage amount of information in the buffer It is also achieved by a configuration in which a monitoring unit and a control unit that gives priority to a port having a large amount of information storage based on the monitoring result of the buffer storage amount monitoring unit and continuously transfers a plurality of information from the port are provided. .

According to this structure, the storage amount of each piece of information in the buffer is constantly monitored by the buffer storage amount monitoring unit, and the amount of one transfer from a buffer having a large storage amount is made larger than that of the other buffers. It is possible to prevent overflow in a large buffer. In order to achieve the above-mentioned other object, the present invention provides a plurality of interface units connected to a plurality of ports, at least one of which is set to a higher transmission speed than others, and a plurality of interface units connected to the interface unit. A plurality of communication control units, a buffer provided for each communication control unit to store information,
In a switching hub that includes a switch unit that connects the communication control units to form a plurality of paths and a switching control unit that determines the paths in the switch unit, a transmission speed detection that detects the transmission speed of the plurality of ports. Section, and the priority of the information transfer processing for the port set to the highest transmission rate based on the detection result of the transmission rate detection section is set to the highest priority, and a plurality of pieces of information are serialized from the port set to the highest priority. The control means for transferring is provided.

According to this structure, the transmission rate of each port is detected by the transmission rate detecting section, the port to be processed is selected on the basis of the detection result, and the amount of reception is large because the transmission rate is high. It is possible to prevent the occurrence of overflow due to the above.

[0020]

1 is a block diagram showing a first embodiment of a switching hub according to the present invention, and FIG. 2 is a block diagram of FIG.
3 is a flowchart illustrating the operation of the switching hub of FIG. The switching hub 100 according to the present invention has the configuration shown in FIG. 8, that is, the switch unit 108, the switching control unit 109, the communication control LSIs 110 _{-1 to} 110 _-n ,
Buffers 111 _{-1 to} 111 _-n , interface unit 11
In contrast to the configuration of 2 _{−1 to} 112 _−n , the switching control unit 109 is provided with a priority setting unit 121.

The priority setting unit 121 is an interface circuit for setting the priority of each port from the network management software 124. This priority setting unit 121
May be a register for writing a high priority port number to the switching control unit 109. Alternatively, any configuration may be used as long as the network management software 124 in a certain area of the memory can write the high-priority port number.

The network management software is usually 124,
A port number input from the outside via the man-machine interface of the network management software is set in the priority setting unit 121 as a high priority port. Next, the operation of the switching hub of the present invention having the above configuration will be described with reference to the flowchart of FIG.
Note that, in FIG. 2, the same reference numerals are used for parts that perform the same processing as that shown in FIG.

First, start with port number X = 1 (step 301), and then X ≧ N (N is the maximum port number)
It is determined whether or not the relationship of is satisfied (step 302).
If the determination result is X <N, X = 1 is set (step 3
03), the determination of X ≧ N is performed again. When X ≧ N is determined, it is determined whether a transfer request is issued from the communication control LSI with the port number X (step 304). When the transfer request is not issued from the communication control LSI of the port number X, the port number X is set to X = X + 1 (step 30
5) The process is returned to step 302. The processing up to this point is as described in FIG.

If it is determined in step 304 that a transfer request has been issued from the communication control LSI with port number X,
It is determined whether the port number X has high priority (step 401). When the priority is not high, the subsequent processing is as shown in FIG.
After executing the processing of steps 306 to 309 shown in 2 and setting the port number X to X = X + 1 (step 309), the processing shifts to step 302.

If port number X has high priority, then Y
(Number of consecutive transfer frames of high priority port) is set to an initial value (step 402). Then, it is determined whether or not Y = 0 (step 403). If Y = 0, the port number X is set to X = X + 1 (step 405),
The process proceeds to step 302. If Y ≠ 0, the switching control unit 109 determines the destination (step 404) and instructs the switch unit 108 to switch the route. Based on this command, the switch unit 108 switches the route (step 406). Further, the switching control unit 109 issues a transfer permission signal to the communication control LSI having the port number X (step 407), and further sets the port number X to Y = Y-1 (step 40).
After 8), the process is returned to step 403, and the subsequent processes are repeatedly executed.

As described above, according to the switching hub having the configuration shown in FIG. 1, in the port m set to the high priority, a plurality of frames are continuously transferred until Y = 0 in steps 403 to 408. However, since the transfer processing of the next port is executed thereafter, there is no fear that the received frame will overflow. FIG. 3 is an explanatory diagram showing the states in the buffer of each port and the order of transfer when the number of frames processed in continuous transfer is set to “4” for a high priority port.

As described with reference to FIG. 14, other bags except
FA 111_-1~ 111_-nIn contrast, the buffer 111_-mIs many
Number of frames 120_-ma~ 120_-mhOwns.
In such a situation, the transfer order is shown in FIG.
The procedure is carried out in the frame 120_-1a→ 120_-2a→ 1
20_-ma→ 120_-mb→ 120_-mc→ 120_-md...
120_{-(n-1) a}→ 120_-naWill be transferred in order. this
Like, buffer 111 _-mOnly multiple frames in succession
Transfer, and transfer only one frame at other ports.

As a result, for example, the port m is 100 Mb.
/ S transmission rate, other ports are 10Mb / s
Even if the port m is set to the transmission speed of 10 times and receives the frame 10 times faster than other ports, the port m
Will never overflow. Transfer of a port connected to a server where communication is concentrated in a client / server system, a port connected to a 100 Mb / s terminal in a mixed transmission system of 10 Mb / s and 100 Mb / s Ethernet, or a port connected to an audio / video terminal in a multimedia system If the switching hub according to the present invention is used for processing, high priority can be set easily by using network management software. With this, compared to the case of using a conventional switching hub,
Frame retransmission processing due to buffer overflow can be prevented, and audio / video frames can be transferred with high priority, so that the performance of the entire system can be easily improved.

FIG. 4 is a block diagram showing a second embodiment of the switching hub according to the present invention. The switching hub 100 shown in FIG. 4 has the configuration shown in FIG. 8, that is, the switch unit 108, the switching control unit 109, the communication control LSIs 110 _{-1 to} 110 _-n , and the buffers 111 _-1 to.
111 _-n, to structure consisting of the interface unit 112 _-1 to 112 _-n, connect the transmission speed detector 122 to the switching control unit 109, the interface unit 112 _-1 to 112 _-n This transmission speed detector 122 The feature is that each transmission speed is taken in.

Note that, in FIG. 4, it is assumed that the switching hub is used as an Ethernet switch, and the interface units 112 _{-1 to} 112 _-n have 10 Mb.
It corresponds to the transmission speed of / s and 100 Mb / s. The transmission rate detection unit 122 constantly monitors each transmission rate from the port 1 to the port n, detects a port number with a transmission rate of 100 Mb / s, and notifies the switching control unit 109 of this. As the transmission rate detecting means, for example, a transmission rate of 100 Mb of IEEE802.3 is used.
/ S Ethernet standard 100BASE-T Physical layer link signaling shown in Chapter 28 for 10Mb / s & 10
The method based on the link pulse specified in 0 Mb / s Auto-Negotiation on twisted-pair can be used. Alternatively, a method of searching the status register indicating the operation state of the communication control LSIs 110 _{-1 to} 110 _-n or the interface units 112 _{-1 to} 112 _-n may be used, or the number of displacements of the received data pulse per unit time may be calculated. A counting circuit may be used.

In the switching hub shown in FIG. 4, the frame transfer priority of a port whose transmission speed is set to 100 Mb / s is set as a high priority, and a plurality of frames are continuously transferred only to the high priority port. However, it is possible to prevent the overflow of the buffer. Details of this operation are as described in the flowchart of FIG. 2 and the continuous transfer process explanatory diagram of FIG. Therefore, the detailed description is omitted.

FIG. 5 is a block diagram showing a third embodiment of the switching hub according to the present invention. The switching hub 100 shown in FIG. 4 has the configuration shown in FIG. 8, that is, the switch unit 108, the switching control unit 109, the communication control LSIs 110 _{-1 to} 110 _-n , and the buffers 111 _-1 to.
111 _-n, to structure consisting of the interface unit 112 _-1 to 112 _-n, is characterized in the configuration of connecting the buffer fullness monitoring unit 123 to the switching control unit 109.

The buffer accumulation amount monitoring unit 123 measures the frame storage amount (accumulation amount) in each of the buffers 111 _{-1 to} 111 _-n and creates priority information for each port based on the result. This priority information is provided to the switching control unit 109. Switching control unit 109
Determines the transfer order based on the obtained priority information, and controls the switch unit 108 based on this.

FIG. 6 is an explanatory diagram showing the frame transfer order of the switching hub having the configuration of FIG. Here, the buffer 111 _{−1 of} port 1 has five frames 11 to 15
Storing buffers for ports 2 to 4 and buffers 111 _-2 to 1
Each of 11 _-4 stores two frames. As described above, the fact that only the buffer 111 _{-1 of} port 1 has a large frame storage amount means that the buffer storage amount monitoring unit 12
3, the switching control unit 109 determines the transfer order so that the frame transfer is started from the port 1 based on this result.

As shown in FIG. 6, first, the frame 11 of port 1 is transferred, and then the frame 12 of port 1 is transferred.
→ Port 1 frame 13 → Port 2 frame 21 →
The transfer is performed in the order of the frame 31 of the port 3 → the frame 41 of the port 4 → the frame 14 of the port 1 → ... In this way, in port 1, which has a larger amount of frame storage than other ports, a plurality of frames (three frames in this example) are transferred simultaneously in succession.

As described above, according to the configuration of FIG. 5, the frame storage amount of the buffer is constantly monitored, and the frame is transferred preferentially from the port having a large storage amount. As a result, the buffer of the specific port overflows. It is possible to avoid the situation.

[0037]

As is apparent from the above, according to the present invention, the priority of the information transfer processing in each of the plurality of ports is set based on the network management software, and the plurality of information is set from the port having the highest priority. Is made to be transferred continuously, so that a specific port will not overflow.

Further, according to the present invention, the storage amount of information in each buffer of each port is monitored, and a plurality of information is continuously transferred from the port having a large information storage amount based on the monitoring result. It is possible to prevent overflow from occurring in a buffer having a large storage amount. Also,
The present invention detects the transmission rate of each of a plurality of ports, and based on the detection result of this transmission rate detection unit, gives the highest priority to the information transfer processing for the port set to the highest transmission rate, and Since a plurality of pieces of information are continuously transferred from the port set as a priority, it is possible to prevent the occurrence of overflow due to a large reception amount due to a high transmission speed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a switching hub of the present invention.

FIG. 2 is a flowchart illustrating the operation of the switching hub of FIG.

FIG. 3 is an explanatory diagram showing a state in a buffer of each port and a transfer order when the number of frames processed in continuous transfer is set to 4 for a high priority port.

FIG. 4 is a block diagram showing a second embodiment of the switching hub of the present invention.

FIG. 5 is a block diagram showing a third embodiment of the switching hub of the present invention.

6 is an explanatory diagram showing a frame transfer order of the switching hub having the configuration of FIG.

FIG. 7 is an explanatory diagram showing the operating principle of the switching hub.

FIG. 8 is a block diagram showing a configuration of a conventional switching hub.

9 is an explanatory diagram showing a connecting operation of the switching hub having the configuration of FIG.

FIG. 10 is a switching control unit and a communication control LSI of FIG.
It is explanatory drawing which shows the communication between.

11 is a flowchart showing a data transfer process in the connection state of FIG.

FIG. 12 is a flowchart showing details of processing performed by the switching control unit of FIG.

FIG. 13 is an explanatory diagram showing a state in a reception buffer of each port and an order in which transfer processing is performed.

FIG. 14 is an explanatory diagram illustrating overflow of a buffer of a port having many received frames.

FIG. 15 is an explanatory diagram illustrating overflow of a port holding a large number of unprocessed received frames.

[Explanation of symbols]

100 switching hub 108 switch unit 109 switching control unit 110 _-1 to 110 _-n communication control LSI 111 _-1 - 111 _-n buffer 112 _-1 to 112 _-n interface unit 114 _-1 to 114 _-n terminals 115 and 116 internal Route 121 Priority setting unit 122 Transmission rate detection unit 123 Buffer storage amount monitoring unit 124 Network management software

Claims (3)

[Claims] 1. A plurality of interface units to which a plurality of ports are connected, a plurality of communication control units to which the interface units are connected, a buffer provided for each communication control unit for storing information, and the communication. In a switching hub including a switch unit that connects a control unit to form a plurality of routes and a switching control unit that determines a route in the switch unit, the priority of information transfer processing at the plurality of ports is set by network management software. A switching hub comprising: a priority setting unit configured based on the above; and a control unit configured to continuously transfer a plurality of pieces of information from the port set as the highest priority by the priority setting unit. 2. A plurality of interface units to which a plurality of ports are connected, a plurality of communication control units to which the interface units are connected, a buffer which is provided for each communication control unit and stores information, and the communication. In a switching hub including a switch unit that connects a control unit to form a plurality of routes, and a switching control unit that determines a route in the switch unit, a buffer storage amount monitoring unit that monitors the storage amount of information in the buffer. And a control means for giving priority to a port having a large amount of information storage based on the monitoring result of the buffer storage amount monitoring unit and continuously transferring a plurality of information from the port. . 3. A plurality of interface units connected to a plurality of ports, at least one of which is set to a higher transmission speed than others, a plurality of communication control units connected to the interface units, and this communication control unit. A switching hub provided with a buffer for storing information, a switch unit that connects the communication control unit to form a plurality of routes, and a switching control unit that determines a route in the switch unit, A transmission rate detecting unit that detects the transmission rates of a plurality of ports, and the priority of the information transfer process for the port that is set to the highest transmission rate based on the detection result of the transmission rate detecting unit is set to the highest priority, and the highest. A switching hub provided with a control means for continuously transferring a plurality of information from a port set as a priority.