JPH11187072A - Packet transmission system inside network and packet terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packet transmitting system and a transmission terminal with which the amount of packet information is controlled so as to equalize the flow rate control of a packet for each connection, and transfer time is shortened while the result of flow rate control is taken into consideration in the terminal without increasing congestion. SOLUTION: A relay network for packets is provided with a preferential value applying means 100 having a function for calculating the priority of transfer information concerning relevant transfer information to be inputted from a terminal to the relay network and also having a function for transferring the above transfer information in relation to the preferential value, and with a filtering means 200 having a probability calculating function for uniquely calculating the preferential value transferred by the preferential value applying means 100 and a stochastic value from that value and also having a function for performing the processing of abandonment and passage corresponding to the stochastic value concerning the transfer information related with the preferential value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network comprising a relay network and a terminal for transmitting and receiving information, wherein when information transmitted from the terminal is transferred in the network, The present invention relates to a network for controlling a transfer method, and particularly to a bandwidth sharing method, a packet discarding method in a node, a transport protocol, and a congestion avoidance rate control method aiming at fair packet discarding.

[0002]

2. Description of the Related Art An embodiment of conventional input amount control will be described with reference to FIG. In the figure, 1001 is a flow monitoring device means, 1002 is an input information monitoring function, 1003 is a priority value embedding function, 1004 is a rate observing means, 1009 is a threshold crossing judgment function, 1010 is a threshold management function, 1011, 1008, 1007, 1005 and 1006 denote signal transmitting means, 10 denotes a transmitting terminal, 11 denotes a means for connecting the transmitting terminal to the priority assigning function, and 12 denotes a means for transferring packets from the flow monitoring device means to the network.

A threshold value is transmitted from the network to the information flow rate monitoring device via a signal line 1011. Signal line 10
The threshold communicated via 11 is retained in the threshold management function. The input information monitoring function in the flow rate monitoring device notifies the rate observing means of the presence or absence of input information from the terminal. The rate observing means observes the amount of input information from the terminal based on the signal from the input information monitoring function. The threshold judgment excess function compares the threshold value provided from the threshold management function with the information amount observed by the rate observation means.
The priority value “1” is embedded in the input information by the priority value embedding function. On the other hand, if the input amount is smaller than the threshold value, control for embedding “0” is performed. Here, the information amount threshold V
As an example, when the information amount is input with the information amount v = 3, the priority value “1” is determined to be larger than the threshold value, and the priority value “1” is embedded.

[0004]

SUMMARY OF THE INVENTION According to the present invention, in an NW where congestion occurs, the flow rate of information passing through a congestion point when congestion occurs is controlled by (1) passing transfer for each of a plurality of connections passing through the congestion point. Control the amount of packet information passing through the network so that each becomes fair, (2) do not spread congestion, and (3) convert the results of NW flow control to rate control between terminals. It is an object of the present invention to efficiently reflect data and shorten transfer completion time.

[0005]

A feature of the present invention to achieve the above object is that a relay network having an information relay function and a terminal connected to the relay network and transmitting / receiving information via the relay network are provided. In a configured network, a function of calculating a priority of transfer information input to a relay network from a terminal and a function of transferring the transfer information in association with the calculated priority value are provided. Priority value assigning means, a priority value transferred by the priority value assigning means, a probability calculation function for uniquely calculating a probability value from the value, and transfer information associated with the priority value is discarded according to the probability value , A network having filter means having a function of performing passage processing.

[Differences from the Prior Art] Conventionally, a means for calculating a threshold value of the amount of information that allows a congested point to pass through the point,
In a network or the like having a means for transmitting the threshold value to the information flow rate monitoring device at the entrance of the network, control has been performed to determine the priority of input information based on the threshold value provided from the network. In order to realize fairness maintenance between connections passing through the same congestion point using this control, it is necessary for the network to provide calculation means capable of calculating a complicated threshold value.

In the present invention, this flow control is divided into a priority control at the entrance and a flow control based on the priority at each congestion point. Can be done with

[0008]

[Embodiment 1] The following is an explanation for carrying out claim 1.

First, the realization of the priority assigning means will be described. FIG. 1 is a diagram illustrating an embodiment of a priority value assigning unit that assigns a value based on the priority to the inside of the input information according to the priority of the input information. In FIG. 1, 10 is a transmitting terminal, 1
00 is a priority value assigning means, 101 is a priority value calculation function, 102
Is an input information monitoring function for monitoring information transferred from the terminal, 103 is a priority value embedding function for inserting a priority value into information from the terminal, 105 is a signal line for transmitting monitoring information from 102 to 101, Reference numeral 106 denotes a signal line for indicating a priority value to be embedded in 101 to 103, 11 denotes information transfer means between the relay network and the terminal, and 12 denotes information transfer means from the priority value assignment means to the relay network.

FIG. 2 is a diagram showing an embodiment of the priority value calculation in FIG. The input information monitoring function determines a priority value from a predetermined priority value determining element.

In this embodiment, A1 and A
2, A3 and A4 are transferred to the priority value assigning means in this order, and the input information monitoring function observes the transfer status and notifies the priority value calculation function. As shown in FIG. 2, the priority value calculation function obtains a priority value from the charge specified by the transmitting terminal and the amount of transfer information. Here, the priority value = 2 is calculated from the charge = B and the transfer amount = 3. The priority value calculating function transfers the priority value = 2 to the priority value embedding function, and the priority value embedding function transfers the priority value 2 to the transfer information strings A1, A2, A3,
The embedding between A4 is realized.

Second, the implementation of the filter means will be described.
FIG. 3 is a diagram for explaining an embodiment of a filter means for performing a process of discarding and passing transfer information based on a priority value embedded in input information. In FIG. 3, reference numeral 200 denotes a filter means, 201 denotes a discard / pass judgment function, 202 denotes a priority value observing function for reading a priority value added to input information to be transferred, and 203 denotes a discard / pass processing of transfer information. Function, 205
Is a signal line that transmits priority value information from 202 to 201,
206 is a signal line that instructs 201 to 203 to discard and pass,
Reference numerals 13 and 14 denote information transfer means in the relay network.

FIG. 4 is a diagram showing a calculation example of the discard judgment in FIG. Based on the priority value transmitted from the priority value observing function, the discard probability for a block of transfer information with the priority value is calculated from the graph of FIG.

In this embodiment, the transfer information A having the priority value 2
A probability of 1/3 is obtained for 1, A2, A3, and A4. By making a pass / drop judgment of the transfer information based on the probability value, the transfer information is transferred with a probability of 1/3 as a result. Control. The results A1 and A4 pass,
A2 and A3 have been discarded.

Next, a network having priority value assigning means and filter means will be described with reference to FIG.

In the figure, reference numeral 20 denotes a receiving terminal, and 15 denotes information transfer means between the relay network and the terminal. Transfer information between terminals is transferred by the network shown in the figure.

According to a second aspect of the present invention, information input to the network is divided into a plurality of packets, a priority field is provided in the input packet header, or the packet is transferred in addition to the packet information. Discard / pass control may be performed.

[Second Embodiment] The discarding by the filter means shown in the first embodiment may be at the time of multiplexing into the same band, as described in claim 3.

The discarding by the filter means shown in the first embodiment may be performed so that the traffic of the passing packets becomes equal for each terminal.

The case where multiplexing is performed on the same band will be described below.

FIG. 6 is a diagram for explaining a network that multiplexes communication between terminals according to the present invention and shares a specific band. In the figure, 10 is a transmitting terminal, 200 is a priority assigning means, 30
0 is the multiplexing unit, 400 is the demultiplexing unit, 20 is the receiving terminal, 11, 12
Is an information transfer means for connecting the terminal to the relay network, 12
Denotes information transfer means for connecting the priority assignment means and the multiplexing section, 16 denotes information transfer means for connecting the multiplexing section and the demultiplexing section, and 15 denotes information transfer means for connecting the demultiplexing section to the receiving terminal.

FIG. 7 shows an embodiment of the configuration of the multiplexing unit. In the figure
200 is a filter means, 301 is a buffer for storing information, 303 is an identifier assigning function for assigning an identifier of multiplexed transfer information, and 302 is a read control unit for controlling reading of transfer information from a connected buffer. Show.

Each symbol below the hyphen is -1 to indicate that the terminal is connected to the transmitting terminal C, and -2 indicates that the terminal is connected to the transmitting terminal B.
Expressed as

As shown in FIG. 6, transmitting terminals C1 and C1
Information is transferred in the order of 2, C3, and C4. Information is transferred from the transmitting terminal B in the order of B1 and B2. By the priority assigning means connected to each terminal, C1, C2, C3,
Priority value 3 is assigned to C4, and priority value 1 is assigned to B1 and B2.
Is given. Here, an example is shown in which a value proportional to the input information amount is given. The transfer information provided with the priority value is transferred to the multiplexing unit. The multiplexing unit performs a process of discarding the information from each terminal using a filter unit, assigns an identifier for identifying the information from each terminal, and arranges each transfer information to output to the transfer unit 16 I do. In the figure, C1, C4, B1, and B2 are shown passing through filter means and are alternately arranged. The separating unit 400 determines whether the information is from the B terminal or the C terminal by using the identifier of the input transfer information, and transfers the information to the transfer unit 15-1 or 15-2 according to each terminal. .

FIG. 7 shows a specific embodiment of the multiplexing unit.
The transfer information input to the multiplexing unit is stored in a buffer after the discard / pass processing by the filter unit and the assignment of the identifier for identifying the terminal by the identifier assignment function. At 200, an example is shown in which the reciprocal of the input priority value is used as the pass probability and discard / pass judgment is performed. In the figure, information having a priority value of 3 from 12-1 is shown to pass through the filter means 200-1 with a probability of 1/3, and as a result, C1 and C2 are accumulated in the buffer. 12-2
Information with priority value 1 from the filter means 20 with probability 1.
0-2, and as a result, B1 and B2 are accumulated in the buffer. The transfer information stored in the buffer is sequentially read and output by the read control function. Results C and B
The transfer information from is equal and equal.

Example 3 The example of Example 2 was evaluated by computer simulation. FIG. 8 shows priority assigning means based on the rate used in the evaluation. A function for recording and recording a fixed measurement unit time Td for each connection, a table for holding an information list of inputs that have passed during the past Td time, and a table for storing a new packet in a packet header when a new packet arrives Implemented by the function of calculating the passing information amount for the Td time including the present from the table in which the packet length information and the input information list are described, and the function of calculating as priority = passing information amount / Td and adding it to the input packet I do.

FIG. 9 shows priority-based filtering means used in this evaluation. Observation function of Q length change, function to calculate priority threshold from observed Q length, discard / pass judgment based on the priority written in the block and the retained priority threshold when inputting the first cell of the block Function, discarding every cell arrival
It is realized by the function of managing the passage processing for each block.
The operation of the filter unit will be described.

First, the observation of the Q length will be described. As the Q length, the following average Q length is observed. The average Q length information is updated each time the first cell of the block arrives. The Q length when the nth packet arrives is Qo (n), and the average Q length is Q (n-
When expressed by 1), Q (n) is calculated according to the calculation using the low-pass filter shown in Expression 1. Q (n) = wQo (n) + (1-w) Q (n-1) ... 1

Next, the calculation of the threshold value Vth will be described. The threshold Vth is updated using the average Q length observed. Time t is a period during which the n-th packet to the (n + 1) -th packet arrive, and Q (n) is represented as Q (t). Assuming that the current priority threshold is Vth (t), the threshold Vth (t) is set at time t1.
Is updated to V'th (t) according to Equation 2. In Equation 2, Qc is a parameter and gives a constant value. The update of this threshold is Δt
It is performed every time. V'th (t) = [(1 + 1 / Q (t)) / (1 + 1 / Qc)] Vth (t) ... 2

Next, a description will be given of packet discard / pass determination when a packet arrives. When the packet arrives, the priority P in the packet is detected, and the block is selectively discarded from the priority threshold Vth (t) and the priority P at that time according to the discard probability B shown below. B = Vth (t) / P (Vth (t) / P <1) ... 3 1 (Vth (t) / P ≧ 1)

The network was a one-link model shown in FIG. A terminal having a link speed of 150 Mbps and a peak speed of 10 Mbps having infinite content is connected to each source. Here, the same rate control as that of the terminal TCP is performed. However, the following points are different. -When a block is discarded, the transmitting terminal surely starts retransmission control after the RTT when the block is discarded. -Use Go-Back-N from lost packets as retransmission control. Perform standard congestion control using a congestion window.

The propagation delay of the link is set to d, and the propagation delay d between the terminal and the node, the propagation delay d between the node and the terminal, and the return path are given only 2d delay without buffer. T = 4d is the round trip delay due to the transmission delay. Let P be the probability of delay Td
(Td) is given by the following equation. P (Td) = Tm + 1 / Ta ・ exp (-Td / Ta) ... 4

An evaluation of the fairness of the passing transfer amount with respect to an increase in the number of connections using a simulation of the above configuration will be described. Each parameter is as follows. Ta in Equation 4
90 ms, Tm 10 ms, threshold update interval Δt = 1 s,
1 packet = 583 bytes, w = 0.0002 in equation 1, Qc = 10
As a block, the number of connections N = 30 from time t = 0
The transfer is started as follows, and after reaching a steady state at time t = 50 s, the connection is established at time t> 50 s at an average exponential distribution interval of 1 s. Every connection transfers an infinite amount of information. In this system, the time change of the transfer amount of each connection is observed for the 30 connections connected from time t = 0, and the average throughput v _i (t) from time t to t + 10s is calculated. Fairness I
ndex is calculated by equation 5 and shown in Table 1.

[Table 1]

The closer this Fairness Index is to 1, the more fair the index. As a result, 30 connections indicate that a fair transfer amount has been achieved. Fairness Index = (Σν _i ) ² / (n × Σν _i ² ) ... 5

[Embodiment 4] FIGS. 11, 12, and 13 show the case where the information transfer amount between terminals is limited by the congestion point.
FIG. 3 is a diagram illustrating that transfer amount control is performed between terminals.

In FIG. 11, 10 is a transmitting terminal, 20 is a receiving terminal,
100 is a priority value assigning means, 400, 401, 402, and 403 are filter means, and 11, 12, 13, 14, and 15 are information transfer connecting means. Here, the priority assigning means assigns a priority value according to the input information amount. The transfer information with the priority value is transferred through the network to the receiving terminal through the filter means. At this time, it is assumed that each filter means can make the amount of passed information fair according to the network condition. Here, the transfer amount of v = 4 is permitted by 13 transfer units, and 12, 14, 15 supposes that a sufficient amount of information transfer with v = 4 or more is possible. In the above network situation, a situation occurs in which the amount of information that passes through the NW is limited for the terminal due to the NW congestion.

FIG. 12 shows an embodiment of the present invention in information transfer from the transmitting terminal under such a situation. When the transmitting terminal transmits at a speed V = 6 which is equal to or higher than V = 4, V =
The information amount of 2 is discarded by the filter 401. The receiving terminal confirms the received information and determines that V = 2 on the way.
It can be confirmed that the amount of information has been discarded. That is, as a result of the transmitting terminal transferring the information amount of v (t1) at a certain time t1, the receiving terminal can measure it as the loss amount b (t1). This b (t1) is notified to the transmitting terminal. As a result, the transmitting terminal has discarded the information output in v (t1) in b (t1),
Change the amount of waste so that it approaches a certain value B, and V (t1 +
τ). Here, v (t1 + τ) = v (t1) × α
An example of calculation using × B / b (t1) is shown.

FIG. 13 shows a flow of the information amount change control described here.

[0039]

According to the intra-network packet transfer system and the packet terminal of the present invention, the input amount in the communication between the terminals is calculated from the value indicated by the priority corresponding to the destination information in the packet. If the input amount calculated by comparing the input amount given in advance with the calculated input amount is large, a means for discarding the corresponding packet with a given probability is provided. With such a method, packet transfer control can be performed without depending on the input / output speed from the network or the terminal. This transfer control does not break down in the network.

Further, according to the method of the present invention, the following three points are also realized. (1) Bandwidth can be shared according to the priority of a packet. (2) The amount of packets passing through the network becomes fair among the transmitting terminals. (3) The time required for a packet to be transferred on the network can be shortened.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a priority value assigning means according to the present invention.

FIG. 2 is an embodiment of calculating a priority value according to the present invention.

FIG. 3 is an embodiment of a filter means in the present invention.

FIG. 4 shows an embodiment of calculating a discard probability according to the present invention.

FIG. 5 is an example of a network connection in the present invention.

FIG. 6 shows a multiplexing embodiment according to the present invention.

FIG. 7 is a configuration example of a multiplexing unit according to the present invention.

FIG. 8 shows priority value assigning means used in the main evaluation.

FIG. 9 shows filter means used in the evaluation.

FIG. 10 is a network used in the evaluation.

FIG. 11 is an example of a relay network connection in the present invention.

FIG. 12 is an embodiment of rate control between terminals according to the present invention.

FIG. 13 is an example of an inter-terminal rate control flow according to the present invention.

FIG. 14 shows conventional priority value assigning means.

[Description of Signs] 10 Transmitting terminal 20 Receiving terminal 100 Priority value assigning unit 200 Filtering unit 300 Multiplexing unit

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kazuhiro Hayashi Nippon Telegraph and Telephone Corporation 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo

Claims (5)

[Claims] 1. A network comprising a relay network having a function of relaying information and a terminal connected to the relay network and transmitting / receiving information via the relay network. A priority value assigning unit having a function of calculating the priority of the transfer information, a function of associating the calculated priority value with the transfer information and transferring the priority value, and a priority value transferred by the priority value assigning unit. And a probability calculation function for uniquely calculating a probability value from the value; and discarding transfer information associated with the priority value according to the probability value;
A network having filter means having a function of performing passage processing. 2. The network according to claim 1, wherein the transfer information is divided into a plurality of pieces, and an information unit having a destination assigned to each of them is input to the network as a packet, and the network also stores the destination information of the packet. A packet transfer service for transferring a packet to a destination by assigning a priority value to each packet by a priority value assigning unit and discarding the packet by a priority value by a filter unit. 3. The network according to claim 1, wherein information communication between two or more sets of terminals is multiplexed in a specific band of the same trunk line, and multiplexing is performed in a band sharing service for sharing the band. A shared packet transfer network, characterized in that packets are discarded according to packet priority and then multiplexed by using the filter means at the head of the section. 4. The packet transfer system according to claim 1, wherein a packet input amount input to the network for each terminal is observed, and a value corresponding to the input amount is set as a priority of a packet from the terminal. A packet transfer network characterized by using a discard function such that a packet from a terminal passes through a filter means of a multiplexing unit and then has a traffic equal to each other for each terminal. 5. A transmitting / receiving terminal has a function of communicating information of passing / non-passing of an information packet inputted into the network, and inputting the information from the transmitting terminal to the network based on the passing / non-passing information. A packet control method having a function of controlling a packet transmission rate, comprising: a transmission terminal having a rate determination function of determining a transmission rate so that packets are always discarded with a certain range of probability.