JPH11284648A - Lan repeating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a LAN repeating device which can automatically switch back pressure by determining the kind of a connected device. SOLUTION: A LAN repeating device has a buffer control means 30 which sends and receives packet information to and from a CSMA/CD control means 32 and a buffer RAM 31, a buffer capacity decision means 34 which determined the remaining capacity of the buffer RAM 31, and a back pressure generating means 35 which sends back pressure packets to the CSMA/CD control means 36 according to the remaining capacity of the buffer RAM 31. The device further has a back pressure function switching means 38 which makes valid or invalid the function for back pressure packet generation according to the kind of a device at a connection destination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a LAN relay device using a buffer among devices for relaying between Ethernet networks.

[0002]

[Prior Art] Connecting Ethernet networks
A LAN relay device is used as a device that performs this operation. This
Routers, bridges, and switches
Switch, etc., and has a function to buffer packets.
ing. Buffer RAM is used as buffer means
However, since the capacity of the buffer RAM is finite,
This causes a problem that the software overflows. The above solution and
And when the buffer is about to overflow,
Back pressure method to force them to stop sending
Proposed. As this back pressure method,
Currently being considered by the Institute of Electrical and Electronics Engineers (IEEE)
Back pressure method (802.3 _XThere is
However, at present, sending a jamming packet
Jamming method to prevent transmission from the end device is the most
Many are used.

The above-mentioned jamming method is effective in preventing the overflow of the buffer, but from a different point of view, there is a disadvantage that the network is stopped due to a problem of the buffer of the relay device.

For example, assuming that a terminal device 4 is connected to a connection device 3 below the relay device 2 as shown in FIG. 2, the connection device 3 is a multiport bridge or an Ethernet switch. , The collision domain of the relay device 2 and the collision domain of the terminals 4 are divided by the connection device 3. Therefore, jamming from the relay device 2 affects only the connected device 3 and does not affect communication between the terminals 4, 4,....

On the other hand, if the connection device 3 is a multi-port repeater, the collision domain of the relay device 2 and the collision domain of the terminal device 4 are the same. This affects not only the device 3 but also all the terminals 4 connected to the connection device 3.

For this reason, when the connection device 3 is a device that divides a collision domain, such as a multiport bridge or an Ethernet switch, the jamming function is turned on and the connection device 3 is turned on like a multiport repeater. In the case of a device that cannot divide the collision domain, it is often set to turn off the jamming function.

[0007] Such a setting is manually set by switching a jumper in the relay device 2 or connecting a management terminal.

[0008]

However, when setting up the network or changing the configuration of the network, the relay device 2 is set in accordance with the type of device connected to the relay device.
It is troublesome to switch the jamming function on and off, and there is a possibility that the jamming function may be incorrectly set during the operation.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a LAN relay device capable of judging the type of a connected device and automatically switching back pressure. To provide.

[0010]

According to a first aspect of the present invention, there is provided a buffer control means for exchanging packet information between a CSMA / CD control means and a buffer RAM. In a LAN relay device having a buffer amount determining means for determining the remaining capacity of the buffer RAM and a back pressure packet generating means for transmitting a back pressure packet to the CSMA / CD control means in accordance with the remaining capacity of the buffer RAM. Back pressure function switching means for switching the function of generating a back pressure packet between valid and invalid according to the type of the back pressure packet.

According to the second aspect of the present invention, the connected device discriminating means for discriminating whether or not the connected device is a repeater, and the back pressure generating function switching means is enabled based on the result.
Toggle disable.

According to the third aspect of the present invention, there is provided a connected device determining means for determining whether or not a connected device is a repeater, an MIB storing means for storing the result in the MIB, and an S to the MIB.
An SNMP management agent means for switching the back pressure packet generation function switching means between valid and invalid by ET.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram illustrating a functional block configuration of a relay device, and FIG. 2 is a diagram illustrating a configuration of a network including the relay device.

(Operation) From the destination address (DA) and the source address (SA) of the packet flowing to the relay device 2, the type of the connection device 3 connected to the end of the relay device 2 can be determined. Based on this information, the jamming function is turned on and off as it is.

(Embodiment) As shown in FIG.
, A terminal 4 (terminal A), a terminal 4 (terminal B),..., A terminal 4 (terminal X). In the relay device 2, the relay device 2
Is assumed to be transmitted from port A to port B (see FIG. 1). The switched or routed packet is sent to the buffer control means 30. The buffer control means 30 stores the packet in the buffer RAM 31. When the packet can be transmitted by the CSMA / CD control means 32, the buffer control means 30 takes out the packet from the buffer RAM 31 and sends the packet to the CSMA / CD means 32. The CSMA / CD control means 32 transmits the packet to the port B connected to the actual medium via the transmission means 33.

In order to prevent the buffer RAM 31 from overflowing, it is necessary to transmit a back pressure packet to the input port A and perform flow control. The buffer amount determining means 34 determines whether or not the buffer RAM 31 is likely to overflow. If the buffer RAM 31 is about to overflow, a back pressure packet is generated by the back pressure packet generating means 35, and the back pressure is transmitted to the input port A by using the CSMA / CD control means 36 and the transmitting means 37. Send a packet.

Back pressure packet switching means 3
Reference numeral 8 switches whether or not to generate a backpressure packet for preventing the buffer RAM 31 from overflowing.
This switching is based on information from the connected device determination unit 39.

If the relay device 2 is a device having an address learning function such as a bridge or a switch, a method for determining whether or not the connection device 3 is a repeater is filed on the same day (Japanese Patent Application No. 10-84806). However, by using this method, it is possible to set the back pressure function to be turned off when it is determined that the connected device 3 is a repeater, and to be turned on otherwise.

Hereinafter, a method for determining the type of the connection device 3 will be described with reference to FIGS. A bridge, a switch, and the like correspond to the relay device 2. The relay device 2
As shown in FIG. 5, a plurality of receiving ports 11,..., A plurality of transmitting ports 12,..., And a frame relay means 10 for transmitting a frame coming in from the receiving ports 11,. Be composed. The operation of the frame relay means 10 is specified in IEEE 802.1D.

As shown in FIG. 7, the port N of the relay device 2
Are connected to the repeater 15, terminals 16 are connected to the end of the repeater 15, and the connected device 3 is connected to the terminal 4
Assume that (terminal Z) is connected. For example, a frame sent from the terminal 16 (terminal A) to the terminal 4 (terminal Z) is transmitted to the terminal 4 (terminal Z) via the repeater 15, the relay device 2, and the connection device 3 (connection device n). Sent to In the relay device 2, as shown in FIG. 7, the frame received from the reception port of the port N is forwarded by the frame relay means 10 (see FIG. 2) and transmitted from the transmission port of the port n.

Next, in FIG. 7, the terminal 16 (terminal A)
When a frame is sent from the terminal device 16 to the terminal device 16 (terminal B), the frame is sent via the repeater 15. At the same time, the frame is sent to the terminal 16 (terminal X) and the relay device 2. However, the relay device 2 analyzes the source address and the destination address of the frame received from the port N, and since it is found that both are the terminals 16 connected to the port N, the frame is filtered, and Will not be sent to this port.

In the above case, there is a possibility that a frame input from the receiving port is filtered due to a reason other than a frame error. Whether a plurality of terminals 16 are connected to the port via the repeater 15, This is only the case where a plurality of terminals 16 are connected on one segment as in 10BASE5. Since it is known on the relay device 2 side whether or not the reception port of the relay device 1 is a port of 10BASE5, the reception port is 10B.
If it is not ASE5 and there is a filtered frame, it can be determined that the device connected to port N is repeater 15 (see FIG. 6).

Next, consider the case where the terminal 20 (terminal N) and the connection equipment 3 (connection equipment 1 to n) are connected to the relay apparatus 2 as shown in FIG. In this case, all the frames received at the receiving port N of the relay device 2 have the same source address. That is, the number of terminals connected to the port N is only one, and the
The number of C addresses is one. However, even when a router is connected to this port, it cannot be distinguished from the terminal at the MAC layer level.

Further, as shown in FIG.
Is connected to a switch 17 and a bridge, and a terminal 16 (terminals A to X) is connected to the switch 17 and the bridge. FIG.
Connects the switch 17 to the port N of the relay device 2. That is, only the repeater 15 of FIG. 7 is replaced with the switch 17, and the other devices are the same as those of FIG. The transmission from the terminal 16 (terminal A) to the terminal 4 (terminal Z) is the same as in FIG. However, the transmission from the terminal 16 (terminal A) to the terminal 16 (terminal B) is filtered at the switch 17 and does not reach the relay device 2. That is, when the connection device is the switch 17 or the bridge, a frame that is filtered at the port N of the relay device 2 does not occur. That is, the number filtered at the port N of the relay device 2 is 0. However, M from the terminal 16 (terminal A) to the terminal 16 (terminal X)
Since the AC address is learned when it is connected to the port N, the MAC address learned at the port N is 2 or more, and it can be determined that the connected device is the bridge or the switch 17.

The functions of filtering and address learning are inherent functions of the relay device 2, and the type of the connected device can be determined only by counting the number of times these functions are executed.

Next, a second embodiment of the present invention will be described. FIG. 3 is a diagram showing a functional block configuration of a management agent unit and a relay device, and FIG. 4 is a diagram showing a configuration of a network including a management manager.

(Operation) As a method further advanced from the first embodiment, the ON / OFF state of the jamming function is determined by combining not only the type of the connection device 3 (see FIG. 4) but also the status of the segment, for example, traffic. When turning off, the type of the connection device 3 is notified to the network management manager using SNMP or the like, and the network management manager determines on / off of the jamming function together with other traffic information, and again checks the SNMP. The relay device 2 is set using, for example,.

(Embodiment) In the first embodiment described above, the relay device 2 itself turns on / off the back pressure function. However, instead of turning on / off the back pressure function based on whether or not the connection device 3 is a repeater, information such as the number of terminals connected to the repeater and traffic on the segment is added. More intelligent methods, such as on / off control, can also be envisioned. In such a method, since the setting standard changes depending on the use of the network system, it is difficult to incorporate this function into the relay device 2 itself. Therefore, a method of making an intelligent setting using the network management manager 1 as shown in FIG. 4 can be considered.

In the relay device 2, the MIB (Management Information) of the type of the connected device 3 is connected.
and a MIB for turning on / off the back pressure function.
FIG. 3 is a configuration diagram thereof. The connected device determination means 39 and the back pressure switching means 38 are connected to the network management agent means 40.

The network management manager 1 GETs the MIB of the type of the connection device 3 from the relay device 2 and determines whether to turn on or off the back pressure function in combination with other information, and determines the result. Based on this, the MIB for turning on / off the back pressure function is set.

[0031]

According to the first to third aspects of the present invention, there is an effect that the switching of the back pressure function of the relay device, which has conventionally been performed manually, can be automated.

[Brief description of the drawings]

FIG. 1 is a diagram showing a functional block configuration of a relay device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a network including the above relay device.

FIG. 3 is a diagram illustrating a functional block configuration of a network management agent unit and a relay device according to a second embodiment.

FIG. 4 is a diagram showing a network configuration including a network management manager according to the first embodiment;

FIG. 5 is a block diagram of a relay device in a method of determining a connected device.

FIG. 6 is a flowchart showing a determination method of the above.

FIG. 7 is a diagram showing a network configuration to which the repeater is connected.

FIG. 8 is a configuration diagram of a network to which the terminal device is connected.

FIG. 9 is a diagram showing a network configuration in which the above switches are connected.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 network management manager 2 relay device 3 connection device 4 terminal device 30 buffer control means 31 buffer RAM 32 CSMA / CD control means 33 transmission means 34 buffer amount determination means 35 back pressure packet generation means 36 CSMA / CD control means 37 transmission means 38 Back pressure packet switching means 39 Connected equipment determination means 40 Network management agent means

Claims (3)

[Claims] 1. CSMA / CD control means and buffer RA
M, a buffer controller for exchanging packet information, a buffer amount determiner for determining the remaining capacity of the buffer RAM, and a buffer controller for determining the remaining capacity of the buffer RAM.
Back pressure packet generating means for sending back pressure packets to the SMA / CD control means.
A LAN relay device comprising an AN relay device having back pressure function switching means for switching between enabling and disabling a function of generating a back pressure packet in accordance with a type of a connection destination device. 2. The LAN relay according to claim 1, wherein the connected device determining means for determining whether or not the connected device is a repeater and whether the back pressure generating function switching means is enabled or disabled according to the result. apparatus. 3. A connected device discriminating means for discriminating whether or not a connected device is a repeater, and an M storing the result in MIB.
2. The LAN relay device according to claim 1, further comprising: an IB storage unit; and an SNMP management agent unit that switches between enabling and disabling the backpressure packet generation function switching unit according to the setting of the MIB.