JP3768847B2 - Traffic control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a traffic control apparatus that maintains an upper limit speed limit for each LAN and guarantees a lower limit speed for each traffic flow in a network that is best-effort type traffic.
[0002]
[Prior art]
As a conventional traffic control apparatus, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 2000-105669. This will be described with reference to FIG. This figure shows a configuration when this traffic control device is adapted to a wired LAN. In FIG. 9, the traffic control device restricts the communication speed to be low when the wired LAN-A (111) is congested by the traffic control device 100.
[0003]
The communication terminal A-1, the communication terminal A-2, and the communication terminal A-3 connected to the LAN-A 111 pass through the traffic control device 100 and communicate with the LAN-B 112 during communication. , B-2, B-3, communication terminals C-1, C-2, C-3 connected to LAN-C113, communication terminals D-1, D-2, D-3 connected to LAN-D114 Can communicate with.
[0004]
FIG. 10 is a block diagram showing a configuration of a conventional traffic control apparatus. The traffic control device includes a LAN-A buffer 101, a route determination unit 102, a LAN-B traffic control unit 103, a LAN-C traffic control unit 104, a LAN-D traffic control unit 105, and a buffer monitoring unit 106. .
[0005]
The LAN-B traffic control unit 103, the LAN-C traffic control unit 104, and the LAN-D traffic control unit 105 receive packets appearing in the LAN-B, LAN-C, and LAN-D, and determine the route. To the unit 102. When the route determination unit 102 receives the packet, the route determination unit 102 transmits the packet to the port to which the packet is to be transmitted.
[0006]
Here, since only the LAN 1A is assumed as the transmission port, the packet is transferred to the LAN-A buffer 101. The LAN-A buffer 101 sequentially stores the packets passed from the route determination unit 102. When congestion occurs in the LAN-A, packets start to stay in the LAN-A buffer 101, and the packet accumulation amount increases.
[0007]
Therefore, it is possible to know the occurrence and resolution of LAN-A congestion by monitoring the accumulated amount of packets. Therefore, the buffer monitoring unit 106 monitors the amount of packets stored in the LAN-A buffer, and when the amount reaches a predetermined amount, the LAN-B traffic control unit 103, the LAN-C traffic control unit 104, and the LAN- Congestion is notified to the D traffic control unit 105.
[0008]
Upon receiving the congestion notification from the buffer monitoring unit 106, the LAN-B traffic control unit 103, the LAN-C traffic control unit 104, and the LAN-D traffic control unit 105 receive the LAN-B, LAN-C, and LAN- Stop data packets from D for a specified period.
[0009]
LAN-B. As a result of the transmission of packets from LAN-C and LAN-D being stopped, the amount of packets stored in the LAN-A buffer 101 is reduced, and congestion is eliminated. Therefore, packets are stopped for LAN-B, LAN-C, and LAN-D according to the allocated bandwidths, so that they are assigned to LAN-B, LAN-C, and LAN-D. The lower limit speed can be guaranteed.
[0010]
[Problems to be solved by the invention]
However, the conventional traffic control device as disclosed in Japanese Patent Application Laid-Open No. 2000-105669 does not have a function to guarantee the bandwidth for each traffic flow, and therefore cannot guarantee the lower limit speed corresponding to the communication protocol such as the TCP / IP protocol There was a problem.
[0011]
That is, when congestion control is possible for LAN-B, LAN-C, and LAN-D with the configuration of FIG. 9, LAN-C is congested in communication from LAN 1A to LAN-B, LAN-C, and LAN-D. At this time, in the conventional traffic control apparatus such as Japanese Patent Laid-Open No. 2000-105669, all LAN-A transmissions are stopped.
[0012]
When performing bandwidth guarantee for each traffic flow, in the case of a traffic flow based on the TCP / IP protocol, the output from the buffer stops at the time of congestion, so the TCP ACK does not reach the source of the TCP data packet. For this reason, the transmission source of the TCP data packet cannot transmit TCP data by TCP flow control.
[0013]
As a result, there is a problem that the lower limit speed cannot be guaranteed because the data amount is suppressed to a small amount. The present invention solves the conventional problems as described above, supports flow control based on the TCP / IP protocol, and fluctuations in traffic flow, and maintains the upper limit speed limit for each LAN and guarantees the lower limit speed for each flow. It is an object of the present invention to provide a traffic control device to be realized.
[0014]
[Means for Solving the Problems]
According to the present invention, the above-mentioned problems are solved by the means described in the claims. That is, the invention of claim 1 is a traffic control device installed so as to relay between at least one LAN accommodating at least one communication terminal and the backbone network, and the LAN passing through the own traffic control device and means for passing I line the lower rate guaranteed upper speed limit and each communication terminal or for each traffic flow and temporarily stores the two-way traffic packet communication for each LAN in between the backbone network and, TCP / means for Ru acknowledgment packet in an IP protocol (TCP ACK) is passed in preference regardless the upper speed limit, a traffic control device, characterized in that it comprises a.
[0015]
In the conventional method, the output of the data packet is stopped for the period specified at the time of congestion, whereas the method of the present invention is different in that the output of the TCP ACK as a specific data packet is not stopped. Thus, TCP ACK only with priority output of the particular data packet is also related to flow control when exceeding the upper speed limit value prevents transmission stop of TCP data packets by flow control in accordance with the TCP / IP protocol, TCP There is an effect that it is possible to guarantee the lower limit speed of the data packet .
[0024]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing an example of a system configuration using a traffic control device according to the present invention, in which numeral 1 is a traffic control device, 2-1 and 2-2 are servers, 3-1 is a backbone network, 3- 2 represents an access network, 4-1 to 4-5 represent terminals, 5 represents an IP network, and 6-1 and 6-2 represent a LAN. In the figure, a traffic control device 1 monitors a traffic flow passing therethrough and guarantees a band for each traffic flow.
[0025]
The traffic control device 1 is located on the access line between the backbone network 3-1 and the access network 3-2. In the access network 3-2, one or a plurality of LAN groups are formed, and an upper limit speed limit value (for example, group 1: upper limit speed limit value g1, group 2: upper limit speed limit g2) according to the transmission speed for each group. ) Is set. Further, a lower limit guaranteed value (for example, a lower limit guaranteed value for UDP flow (fl1) and a lower limit guaranteed value for TCP flow (fl2)) is set for each traffic flow.
[0026]
FIG. 2 is a block diagram showing the configuration of the traffic control apparatus according to the present invention. The traffic control device includes a route determination unit 11, a control unit 16 (16-1, 16-2), a UDP flow buffer 12 (12-1, 12-2), and a TCP flow buffer 13 (13-1, 13-). 2) The priority buffer 14 (14-1, 14-2) and the traffic monitoring unit 15 (15-1, 15-2).
[0027]
At the time of data packet input, the route judgment unit 11 distinguishes each group and each traffic flow (UDp flow, TCP flow, etc.) and queues them in a buffer. Until the upper speed limit value is reached at T, the traffic flow is preferentially output according to the lower speed guarantee value. If the counter exceeds the upper speed limit value within time T, output is stopped. The priority buffer queues the data packet determined to be the designated data packet by route determination and immediately outputs it.
[0028]
FIG. 3 is a flowchart showing the operation of the traffic control apparatus according to the present invention, and corresponds to the invention of claim 1 . FIG. 4 shows a sequence diagram of a lower limit speed guarantee method using the conventional method and claim 1 of the present invention. FIG. 4 shows an operation procedure for group 1 as an example. Here, as an example, the upper limit limit g1 of the group 1 is 7 Packets, the UDP flow lower limit speed guarantee value fl1 is 3 Packets, and the TCP flow lower limit speed guarantee value fl2 is 2 Packets.
[0029]
In the conventional method, since the UDP flow is connectionless, as shown in FIG. 4 (a), even if the output is stopped, a fixed amount is input to the UDP flow buffer. Data packets are stored and the lower speed guarantee is activated.
[0030]
On the other hand, when the output of the TCP flow is stopped due to the upper limit speed limit, the TCP ACK does not reach the host side, and the data packet is not accumulated in the TCP flow buffer, so the lower limit speed guarantee does not function. On the other hand, when the invention of claim 1 is used, as shown in FIG. 4 (b), when only a TCP ACK is designated as a data packet to be preferentially relayed, it is output even when output exceeding the upper limit is stopped. Accelerate the accumulation of TCP data in the buffer.
[0031]
When the method of the present invention is used, the TCP ACK packet is always output as soon as it arrives, so the TCP data is buffered up to the maximum window size even when output is stopped, thereby realizing the guaranteed minimum speed of the TCP flow. It becomes possible.
[0032]
Figure 5 shows the lower speed limit assurance method in flow chart showing the control of the lower limit speed of each traffic flow averaged during slot Rahikkufuro fluctuation occurs guaranteed, there traffic flows belonging to the group 1 (flow 1). Figure 6 shows an operation procedure of the lower rate guaranteed averaged during slot Rahikkufuro fluctuations occur.
[0033]
The figure shows an operation procedure of the UDP flow of group 1 as an example. In order to realize the guarantee of the average band with respect to fluctuations in traffic flow, a counter Cl1 for monitoring the data amount of the lower limit speed guarantee output for each traffic flow is used. Assume that the lower limit speed guarantee value is fl1 (3 packets), and the upper limit speed guarantee value is g1 (5 packets).
[0034]
If the lower limit speed guarantee value of 3 packets does not exceed the value as shown in FIG. 6A, the data amount counted in Cl1 is converted into cumulative carry-over for the next T time (6-1) (new fl ′ = fl + min (old fl'-Cl, L): 4 = 3 + (3-2)), and the converted lower limit speed guarantee value is used. At the next T time (6-1), the number of data packets for which the lower limit speed is guaranteed is 4 packets, and the total time of T and the next T time (6-1) is 6 packets.
[0035]
It is possible to guarantee 3 packets of the lower limit speed guarantee value fl1 by averaging over time. Similarly, when the lower limit speed guarantee value 3 packets are exceeded as shown in FIG. 6B, cumulative carryover conversion (new fl ′ = fl + min (old fl′−Cl, L): 2 = 3 + (3-4)), and the converted lower limit speed guarantee value is used. At the next time T (6-2), the number of data packets that guarantee the lower limit speed is two. The time of T and the time of the next T (6-2) are 6 packets, and 3 packets of the lower limit speed guarantee value f11 can be guaranteed on average over time.
[0036]
Figure 7 shows a flow chart for performing the maintenance of the upper speed limit of the average during slot Rahikkufuro fluctuations occur. FIG. 7 is a diagram showing a method of limiting the upper limit speed of group 1. Figure 8 shows a maintenance operation procedure of the upper speed limit of the average during slot Rahikkufuro fluctuations occur.
[0037]
FIG. 8 uses, as an example, a counter Cg1 that monitors the data amount of the upper limit speed limit that Group 1 has passed. The upper limit speed guarantee value is g1 (g1: 5 packets). If the upper limit speed of 5 packets is not exceeded during time T, the amount of data counted in Cg1 is converted into cumulative carry-over (new g ′ = g + min (old g′−Cg) for the next T time (8-1). , L): 7 = 5 + (5-3)), and the converted upper limit speed limit value is used.
[0038]
At the next T time (8-1), the upper limit speed limit data packet is up to 7 packets, and the total of the T time and the next T time (8-1) is 10 packets. It is possible to maintain 5 packets that are upper limit speed limit values on an average over time.
[0039]
【The invention's effect】
As described above, in the first aspect of the present invention, the output of the data packet is not stopped for the period specified by the conventional method at the time of congestion, but the output of the TCP ACK as the specific data packet is not stopped. The point is different. Thus, in the invention of claim 1, TCP data packets by also preferentially outputted only TCP ACK as the specific data packets associated with flow control, flow control in accordance with the TCP / IP protocol when exceeding the upper limit speed value It is possible to prevent the transmission stop of TCP and to guarantee the lower limit speed of the TCP data packet .
[0041]
The invention of FIGS. 5 and 6 has a counter (Cl) for monitoring the amount of data packets output during the time T for each traffic flow, and guarantees the lower limit speed of the next unit time T when the unit time T is reached. It is a traffic control device provided with means for setting a value to fl + min (fl′−Cl, L) (fl ′ changes every unit time T and is a lower limit speed guarantee value in the immediately preceding unit time T). As a result, it is possible to obtain an effect of guaranteeing a lower limit speed guarantee value averaged for a traffic flow having fluctuations that are not received at a constant speed.
[0042]
The invention of FIGS. 7 and 8 has a counter (Cg) that monitors the amount of all packets output during the time T from the traffic control device. When the unit time T is reached, the upper limit of the next unit time T is reached. It is a traffic control device comprising means for setting a speed limit value to g + min (g′−Cg, L) (g ′ changes every unit time T and is an upper limit speed limit value in the immediately preceding unit time T). . As a result, it is possible to maintain an upper limit speed limit value that is averaged with respect to the total traffic not received at a constant speed.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a system configuration using a traffic control device according to the present invention.
FIG. 2 is a block diagram showing a configuration of a traffic control device according to the present invention.
FIG. 3 is a flowchart showing the operation of the traffic control device according to the present invention.
FIG. 4 is a sequence diagram of a lower limit speed guarantee method.
FIG. 5 is a flowchart showing control for guaranteeing a lower limit speed for each traffic flow averaged when a traffic flow fluctuation occurs.
FIG. 6 is a diagram illustrating an operation procedure of a UDP flow of group 1;
FIG. 7 is a diagram showing a method for limiting an upper limit speed of group 1;
FIG. 8 is a diagram illustrating an operation procedure for maintaining an average upper limit speed limit when traffic flow fluctuation occurs.
FIG. 9 is a diagram showing a configuration when a conventional traffic control device is applied to a wired LAN.
FIG. 10 is a block diagram showing a configuration of a conventional traffic control device.
[Explanation of symbols]
1 traffic control device 2-1, 2-2 server 3-1, backbone network 3-2 access network 4-1, 4-5, terminal 5, IP network 6-1, 6-2 LAN
11 Path determination unit 12-1, 12-2 UDP flow buffer 13-1, 13-2 TCP flow buffer 14-1, 14-2 Priority buffer 15-1, 15-2 Traffic monitoring unit 16-1, 16-2 Control unit

Claims (1)

A traffic control device installed to relay between at least one LAN accommodating at least one communication terminal and a backbone network,
Bidirectional traffic for packet communication between the LAN passing through its own traffic control device and the backbone network is temporarily stored to limit the upper speed limit for each LAN and guarantee the lower limit speed for each communication terminal or traffic flow. Means to pass through ,
Means for the TCP / IP protocol in acknowledgment packet (TCP ACK) Ru passed in preference regardless the maximum speed limit,
A traffic control device comprising:

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