JP2000183960A - Frame relay terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frame relay terminal for setting the priority of frame service disposal at the congestion of a frame relay network. SOLUTION: This terminal is a frame relay terminal for connecting frame relay networks. Then, the priority of a frame to be transmitted to the frame relay network is communicated from the protocol of a network layer 303 or more in an OSI basic reference model to the frame relay protocol of a data link layer 302, and '1' is autonomously assigned to the discardability display bit of the frame whose priority is low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frame relay for connecting a local area network (hereinafter referred to as "LAN") composed of a plurality of PCs (personal computers), a host computer, a telephone, and the like to a frame relay network. About the terminal.

[0002]

2. Description of the Related Art Recently, IP (Information Pr
ovider) As a means of packetization, the introduction of frame relay (one of the data relay / exchange methods) is in progress.

FIG. 1 is a configuration diagram showing a frame relay network having a general frame relay terminal, and FIG. 2 is a frame configuration diagram showing a frame configuration in a frame relay. In FIG. 1, 101 is a frame relay network, 102 is a frame relay terminal, 103 is a telephone network composed of a plurality of telephones and a PBX, 104 is a host computer that performs core business, and 105 is a LAN composed of a plurality of PCs. is there. In FIG. 2, reference numeral 201 denotes a frame configuration of a frame relay, and 202 denotes a frame relay address.

A conventional operation in the frame relay terminal 102 of the general frame relay network configured as described above will be described. Frame relay terminal 10
2 is a voice frame from the telephone network 103, a core business frame from the host computer 104, the LAN 10
5 are transmitted to the frame relay network 101 in such a manner as to integrate the data communication frames from the frame 5. Here, when network congestion occurs in the frame relay network 101, the frame relay address 202
Is set to "1", and the frame whose DE bit is "1" is preferentially discarded.

[0005]

However, in the above-mentioned conventional frame relay terminal, frames having completely different communication characteristics, such as a voice frame, a core business frame, and a data communication frame, have to be considered in real time (priority). Therefore, there is a problem that frames with high priority may be discarded when network congestion occurs.

This frame relay terminal is required to be able to set the priority of frame service discarding when the frame relay network is congested.

[0007] It is an object of the present invention to provide a frame relay terminal capable of setting the priority of frame service discarding when the frame relay network is congested.

[0008]

SUMMARY OF THE INVENTION In order to solve this problem, a frame relay terminal according to the present invention is a frame relay terminal for connecting to a frame relay network. It is configured to notify the frame relay protocol of the data link layer from the protocol of the network layer or higher in the reference model and autonomously assign “1” to the discardable indication bit of the low priority frame.

As a result, a frame relay terminal capable of setting the priority of frame service discarding when the frame relay network is congested is obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A frame relay terminal according to a first aspect of the present invention is a frame relay terminal for connecting a frame relay network, wherein the priority of a frame to be transmitted to the frame relay network is determined in the OSI basic reference model. A protocol at the network layer or higher is notified to the frame relay protocol at the data link layer, and "1" is autonomously assigned to the discardable indication bit of the low-priority frame. The priority of discarding is set, and when the frame relay network is congested, it is possible to prevent a frame with a high priority from being discarded.

[0011] A frame relay terminal according to claim 2 is
A frame relay terminal for connecting a frame relay network, wherein the priority is classified into three levels of high, medium, and low for each service, and a frame relay such as a normal state, a lightly congested state, a heavy congested state, a discarded state of all frames, and the like. In accordance with the state of the network, "1" is assigned to the discardable indication bit in three stages. The priority of service discarding when the frame relay network is congested is set, and the priority is high. This has the effect of preventing the service from being discarded.

[0012] A frame relay terminal according to claim 3 is
A frame relay terminal for connecting a frame relay network, the service of a frame transmitted to the frame relay network.
The priority of the application can be set for each data link connection. The priority of service / application discarding when the frame relay network is congested is set, and the control of frame relay communication according to the network usage status is set. Has the effect that it becomes possible.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. (Embodiment 1) A frame relay network having a frame relay terminal according to Embodiment 1 of the present invention is shown in FIG.
It is as follows. What makes the frame relay terminal according to the present embodiment different from the conventional technology is the function and operation of the frame relay terminal.

Table 1 shows types of frames flowing in the frame relay network 101 and their priorities.

[0015]

[Table 1]

As shown in (Table 1), the core business system (SN)
A (Systems Network Architecture) frame and voice system (Voice Over Frame Relay)
y, etc.) The priority of the frame is high, and the priority of the normal data communication frame is low.

FIG. 3 shows OSI (Open System Interface).
FIG. 3 is a correspondence diagram showing correspondence between a basic reference model and an actual communication protocol. FIG.
, 300A is OSI basic reference model, 300B
Is the protocol, 301 is the first physical layer, and 302 is the second physical layer.
Layer, a data link layer, 303, a third layer, a network layer, 304, a fourth layer, a transport layer, and 305, a fifth layer.
The layer session layer, 306 is a sixth presentation layer, and 307 is a seventh application layer.

Next, the operation of the frame relay terminal 102 in the present embodiment will be described. In FIG. 1, when a frame to be transmitted to the frame relay network 101 is received by the frame relay terminal 102, the frame relay terminal 102 uses a protocol of the network layer (third layer) 303 or higher in the OSI basic reference model 300A from the data link layer (2nd layer) The frame type is notified to the frame relay protocol corresponding to 302. If the frame relay terminal 102 determines that the frame is a data communication frame (a frame with a low priority), the DE bit is autonomously set to “1” (can be discarded) in the frame relay protocol of the frame relay terminal 102. ) And the frame relay network 10
When network congestion occurs in 1, the data communication frame having a low priority is preferentially discarded.

As described above, according to the present embodiment, the priority of a frame transmitted to the frame relay network 101 is determined by the OS.
Network layer 30 in I basic reference model 300A
Notifying the frame relay protocol of the data link layer 302 from three or more protocols,
For example, by autonomously assigning “1” to the DE bit (discardable indication bit) of the data communication frame, it is possible to set the priority of discarding the frame when the frame relay network is congested. At the time of network congestion, it is possible to prevent a frame having a high priority, for example, a core business system frame from being discarded.

(Embodiment 2) A frame relay network having a frame relay terminal according to Embodiment 2 of the present invention is as shown in FIG. The differences between the frame relay terminal according to the present embodiment and the first embodiment are the functions and operations of the frame relay terminal.

FIG. 4 is a priority example showing the types of applications and their priorities in a data communication frame. As described above, the data communication frame has a lower priority than the core business frame and the voice frame, and as shown in FIG. 4, even in the digital communication frame, there is real-time property, that is, upper and lower priorities. I do.

Next, the operation of the frame relay terminal 102 according to the present embodiment will be described. In the frame relay terminal 102, the priority of the frame is provided in three stages of high, medium, and low, and the data of the application having a high real-time property such as the main business frame and the voice system frame is set to “high”, and the WWW and the data transfer are set to “medium”. Communication frame,
Data communication frames of other applications such as e-mail are classified as "low". Then, the frame relay terminal 102 transmits a frame to the frame relay network 101 in a normal state where the network is not congested.
"1" is assigned to the DE bit in the address field of the frame only in the frame classified as "low", and when the network is in a congested state, "1" is assigned to the DE bit in the frame classified as "medium" or "low". . It should be noted that which frame DE bit is assigned “1” is not only classified into the congestion state and the normal state, but is also classified into fine classifications such as the normal state, the light congestion state, the heavy congestion state, and the all-frame discard state. It can be applied, and the fine classification may be applied for each frame and each application.

As described above, according to the present embodiment, the priority is classified into three levels of high, medium, and low for each frame and each application (that is, for each service), and is classified into a normal state, a light congestion state, and a heavy congestion state. By assigning the discardable indication bit to "1" stepwise in three stages according to the state of the frame relay network such as the state and the state of discarding all frames, priority is given to service discarding when the frame relay network is congested. Since the degree can be set, it is possible to prevent a high-priority service from being discarded and a low-priority service from being left.

(Embodiment 3) FIG. 5 is a configuration diagram showing a frame relay network having a frame relay terminal according to Embodiment 3 of the present invention.

In FIG. 5, 501, 508, 509,
Reference numeral 510 denotes a frame relay terminal connected via a frame relay network; 502, a telephone network including a plurality of telephones and a PBX; 503, a host computer for performing core business; 504, a LAN including a plurality of PCs; ,
Reference numerals 506 and 507 denote frame relay terminals 510 and 50, respectively, in the frame relay network.
8, 509, and 510, which are data link connections (hereinafter, referred to as “PVC”) of the fixed connection of the other party.

The operation and the like of the thus configured frame relay network will be described. The frame relay terminal 501 receives a frame transmitted from the telephone network 502, the host computer 503, and the LAN 504 to the frame relay network. Then, in the frame relay network, the frames are classified according to the destinations, such as PVCs 505, 506, and 507, and transmitted. In this case, the frames received by the frame relay terminals 508, 509, and 510, which are the destinations, are not mixed with backbone-related frames, voice-related frames, and data-communication-related frames. Often biased toward frames. Therefore, in the frame relay terminal 501, the user of the frame relay terminal 501 can set a priority for a specific service application regardless of a known priority scale for each PVC for the frame relay network. Then, in the frame transmitted to the frame relay network, “1” is assigned to the DE bit of the address field of the frame set to have low priority of the service application in the PVC.

As described above, according to the present embodiment, the priority of the service application of the frame transmitted to the frame relay network is determined by the data link connection (PV
C) By enabling setting for each of the C), "1" can be assigned to the DE bit (discardable indication bit) of the address field of the frame set to have a low priority of the service application in the PVC. It becomes possible to control frame relay communication according to the network usage status.

[0028]

As described above, according to the frame relay terminal of the first aspect of the present invention, a frame relay terminal for connecting a frame relay network, wherein the priority of a frame transmitted to the frame relay network is determined. By notifying the frame relay protocol of the data link layer from the protocol of the network layer or higher in the OSI basic reference model and autonomously assigning "1" to the discardable indication bit of the low-priority frame, when the frame relay network is congested, Since the priority of frame discarding can be set, it is possible to prevent a frame with a high priority, for example, a core business system frame, from being discarded without consideration of the priority when the frame relay network is congested. The effect is obtained.

According to the frame relay terminal of the present invention, a frame relay terminal for connecting a frame relay network, wherein the priority is classified into three levels of high, medium and low for each service, By assigning "1" to the discardable indication bit in three stages in accordance with the state of the frame relay network such as the light congestion state, the heavy congestion state, the all frame discarded state, etc. Since the priority of discarding can be set, it is possible to obtain an advantageous effect that it is possible to prevent a frame having a high priority from being discarded and a service having a low priority from being left.

According to a third aspect of the present invention, there is provided a frame relay terminal for connecting a frame relay network, wherein the priority of a service application of a frame transmitted to the frame relay network is set for each data link connection. By making it possible, "1" can be assigned to the discardable indication bit of the address field of the frame set as having a low priority of the service application in the data link connection, so that it can be assigned according to the network usage status. An advantageous effect that control of frame relay communication becomes possible is obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a frame relay network having a general frame relay terminal.

FIG. 2 is a frame configuration diagram showing a frame configuration in a frame relay.

FIG. 3 is a correspondence diagram showing correspondence between an OSI basic reference model and an actual communication protocol;

FIG. 4 is a priority example diagram showing types of applications and their priorities in a data communication frame;

FIG. 5 is a configuration diagram showing a frame relay network having a frame relay terminal according to a third embodiment of the present invention;

[Explanation of symbols]

101 Frame Relay Network 102, 501, 508, 509, 510 Frame Relay Terminal 103, 502 Telephone Network 104, 503 Host Computer 105, 504 LAN 201 Frame Relay Frame Configuration 202 Frame Relay Address 300A OSI Basic Reference Model 300B Protocol 301 Physical Layer 302 Data link layer 303 Network layer 304 Transport layer 305 Session layer 306 Presentation layer 307 Application layer 505, 506, 507 Data link connection (PVC)

Claims (3)

[Claims] 1. A frame relay terminal for connecting a frame relay network, wherein the priority of a frame to be transmitted to the frame relay network is notified from a network layer or higher protocol in the OSI basic reference model to a data link layer frame relay protocol. A frame relay terminal for autonomously assigning "1" to a discardable indication bit of a low priority frame. 2. A frame relay terminal for connecting a frame relay network, wherein the priority is high, medium, or low for each service.
Classifying into three stages, and assigning "1" to the discardable indication bit in a stepwise manner for the three stages according to the state of the frame relay network such as a normal state, a light congestion state, a heavy congestion state, and a whole frame discard state. A frame relay terminal characterized by the following. 3. A frame relay terminal for connecting a frame relay network, wherein the priority of a service application of a frame transmitted to the frame relay network can be set for each data link connection. .