JP2002124985A - Transmitting device and communication system and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmitter capable of efficiently transmitting packet data belonging to a band-guaranteed flow packet data belonging to a best effort type flow through the same communication network. SOLUTION: This transmitting device is provided with a packet queue managing part 32 for classifying inputted packet data for each flow to which the packet data belong, and for outputting the classified packet data for each flow in the order of inputs; and a transmission timing deciding part 35 for deciding the transmission timing of the packet data belonging to a band-guaranteed flow by considering the band guarantee of the flow, and for deciding the transmission of packet data belonging to a best effort type flow in the transmission timing in which the packet data belonging to the band-guaranteed flow are not transmitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitting apparatus, a communication system, and a transmitting method for transmitting packet data of a bandwidth guaranteed flow and packet data of a best effort flow through the same communication network.

[0002]

2. Description of the Related Art For example, as shown in FIG.
Network 10₁ , 10 _Two As a communication network
To transmit digital data for broadcast and Internet
In communication systems that provide services such as mobile telephones,
Transmission device 11₁ , 11_Two And the relay device 12
TCP / IP (Transmiss
ion Control Protocol / Internet Protocol)
To the receiving device 13 in a packet format according to the communication protocol.
And sent. In this case, the transmission device 11₁ , 11
_Two And the relay device 12 are connected to a plurality of flows (systems).
Transmits and relays content with guaranteed bandwidth
Must be used to avoid interference between flows during transmission
Queues are assigned to each flow and stored in packet data.
Using the stored identifier, the key of the flow to which the packet belongs
Packet data into the queue in order
Packet data from the head of each queue according to
And send. The method is, for example, Joins Nagle, OnPa
cket Switched with infinite Storage, IEEE Transact
ion on Communications Vol.35 No.4 pp.435-438, Apr
1987.

[0003] For example, as shown in FIG. 12, if there is a flow identifier ID ₁ ~ID ₁₀ is assigned as a flow for performing bandwidth guarantee, the transmission device 11 _1, 11 ₂ and the relay apparatus 12, for example, the using the identifier in the header shown in Figure 13 of the packet data, the identifier ID ₁ ~ID ₁₀
The packet each placed in a queue Qa ₁ ~Qa _10.
The following example illustrates a case where the packet data has a fixed length.

[0004] To guarantee the bandwidth is to guarantee that a fixed amount of data is transmitted per unit time. When data is transmitted as a certain chunk such as packet data, transmission of packet data is performed. The interval will be guaranteed. The transmission interval of the packet data is, for example, scheduled in advance, and when a plurality of packets are scheduled at the same transmission timing, one packet is selected and transmitted according to a predetermined algorithm.

[0005] For example, in the transmission devices 11 ₁ and 11 ₂ and the relay device 12, as shown in FIG.
Consider the case of Sukejuru when to send the head of the packet data of the _{1 ~Qa 10.} In this case, and sends the first packet in the queue Qa ₃ and Qa ₁₀ is a conflict time t _1, according to a predetermined algorithm, for example,
Transmission of the first packet of the queue Qa ₁₀ is selected. Then, as shown in FIG. 15, a new schedule is made, the first packet in the queue Qa ₃ is sent at time t _2. Thereafter, as shown in FIG. 15, for possible conflicts, the transmission of the first packet in the queue Qa ₁ at time t _3,
Transmission of the first packet of the queue Qa ₁₀ at time t _5, the transmission of the first packet in the queue Qa ₁ at time t _6, time t ₇
Transmission of the first packet of the queue Qa _2, transmission of the first packet of the queue Qa ₃ at time t ₈ is performed in the order in. The transmission of the first packet of the queue Qa ₁ and Qa ₁₀ competes at time t _9, according to a predetermined algorithm, for example, the transmission of the first packet in the queue Qa ₁ is selected.

The network 10 shown in FIG.
₁ and 10 ₂ are so-called best-effort type, which is not required to guarantee the bandwidth but is required to be transmitted at the earliest possible timing, in addition to the packet data of the flow whose bandwidth is guaranteed as described above. The packet data of the flow is also transmitted. The transmission devices 11 ₁ and 11 ₂ and the relay device 12 transmit packet data of the best effort type flow so as not to affect the guaranteed bandwidth type flow as much as possible. For example, the transmitting device 11 ₁ , 1
1 ₂ and the relay apparatus 12, for example, as shown in FIG. 16, the queue Qa ₁ when the transmission timing of the first packet of ～Qa ₁₀ is scheduled, the time t ₄ when packet data to be transmitted is not scheduled, t ₁₁ ,
In t _14, and transmits the packet data of best effort flows.

As described above, packet data has a fixed length.
In the case of, the transmission device 11₁ , 11 _Two And relay device 1
2 indicates that the packet data of the guaranteed bandwidth flow is scheduled.
Best Effort Flow at Untimed Time
Is transmitted.

[0008]

However, in the above-mentioned conventional communication system, if the packet data is not of a fixed length, the following problems occur. That is, when the packet length is not fixed, the transmission devices 11 ₁ and 11 ₂ and the relay device 12 perform best-effort-type attempts to transmit in each of the periods during which packet data to be transmitted is not scheduled within the period. It is determined whether or not the packet data of the flow can be transmitted, and only when it is determined that the packet data can be transmitted, the packet data of the best effort type flow is transmitted. For example, the networks 10 ₁ and 10 ₂ are Ethernet (registered trademark) having a total bandwidth of 100 Mbps, and the bandwidth is 5 Mbps,
When a band-guaranteed flow with one packet data of 64 bytes is scheduled, the packet data transmission of the flow is performed with a packet transmission time of 10 μsec and a packet transmission interval of 102 μsec as shown in FIG. Seconds. In this situation, the transmitting apparatus 11 _1, 11 the ₂ and the relay device 12 is to send a best-effort packet 1500 bytes bandwidth 100Mbps, the transmission of the packet it takes a 120μ seconds, send 11 _1, 11 ₂ and the relay device 12 can not indefinitely transmit a packet of the best effort.

That is, in the conventional communication system, the transmission of packet data of the best-effort flow is permitted only within a range that does not affect the bandwidth-guaranteed flow. The situation that transmission cannot be performed occurs.

[0010] The present invention has been made in view of the above-mentioned problems of the prior art, and provides a method for comparing packet data of a bandwidth-guaranteed flow and packet data of a best-effort flow through the same communication network. It is an object of the present invention to provide a transmission device, a communication system, and a transmission method that can appropriately avoid a situation in which packet data of a best-effort flow is not transmitted at all with a simple, small, and simple configuration. Another object of the present invention is to provide a transmission device, a communication system, and a transmission method that can reduce the influence of transmission of packet data of a best-effort flow on a guaranteed bandwidth flow.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art and achieve the above-mentioned object, a transmitting apparatus according to a first aspect of the present invention comprises a band-guaranteed flow and a best-effort flow. A transmission device for transmitting packet data of a plurality of flows including: classifying input packet data for each of the flows to which the packet data belongs, and outputting the classified packet data in the order of input for each flow An input / output control unit that determines the transmission timing of the packet data belonging to the bandwidth-guaranteed flow in consideration of the guaranteed bandwidth of the flow, and the transmission timing at which the packet data belonging to the bandwidth-guaranteed flow is not transmitted Transmission timing determining means for deciding to transmit the packet data of the best effort type flow, and The packet data, in the order in which they are outputted from the output control means, a transmission means for transmitting at a transmission timing said determined.

The operation of the transmitting apparatus according to the first invention is as follows. The input / output control means classifies the input packet data for each flow to which the packet data belongs, and outputs the classified packet data for each flow in the order of input. The following processing is performed in parallel with this processing. That is, the transmission timing determining unit determines the transmission timing of the packet data belonging to the guaranteed bandwidth type flow in consideration of the guaranteed bandwidth of the flow. Then, the transmission timing determining means determines to transmit the packet data of the best effort type flow at a transmission timing at which the packet data belonging to the bandwidth guaranteed type flow is not transmitted. And, by the transmitting means, the packet data of the flow, in the order of output from the input / output control means,
The transmission is performed at the determined transmission timing.

[0013] In the transmission apparatus of the first invention, preferably, the transmission timing determination means needs to transmit a plurality of packets of the band guarantee type flow at the same transmission timing in order to perform the band guarantee. In some cases, selecting one band-guaranteed flow from the plurality of band-guaranteed flows based on a predetermined priority, and transmitting the packet data of the selected flow at the transmission timing. decide.

In the transmitting apparatus according to the first invention, preferably, the transmission timing determining means has a timer for generating time information used to determine a timing for transmitting the packet data, and For each of the guaranteed flows, time information indicating the time obtained by subtracting the time when the packet data belonging to the flow is determined to be transmitted next from the time indicated by the time information is generated, and A transmission timing at which the packet data belonging to the guaranteed bandwidth type flow is not transmitted is specified based on the transmission timing.

[0015] In the transmission apparatus according to the first aspect of the present invention, preferably, the transmission timing determining means is configured to perform the best effort if the time information of all the bandwidth guaranteed flows indicates a positive value. Decide to send packet data of type flow.

In the transmitting apparatus according to the first invention, preferably, the transmission timing determining means uses the band allocated to the flow and the data amount of packet data to be transmitted of the flow. The next transmission of the packet data belonging to the flow is determined.

In the transmission apparatus according to the first invention, preferably, the transmission timing determining means is provided corresponding to each of the flows, and defines a time when the packet data belonging to the corresponding flow is transmitted next. Have a plurality of timers.

Further, in the transmitting apparatus according to the first invention, preferably, the length of the packet data is variable.

The communication system of the second invention transmits packet data of a plurality of flows including a band-guaranteed flow and a best-effort flow to the receiving device via the communication line. A communication system having a transmitting device, input / output control means for classifying input packet data for each flow to which the packet data belongs, and outputting the classified packet data for each flow in the order of input; and The transmission timing of the packet data belonging to the bandwidth guaranteed type flow is determined in consideration of the guaranteed bandwidth of the flow, and the best effort type is determined at the transmission timing not transmitting the packet data belonging to the band guaranteed type flow. Transmission timing determining means for determining to transmit the packet data of the flow; The data, in the order in which output from the output control means, a transmission means for transmitting at a transmission timing said determined.

A transmission method according to a third aspect of the present invention is a transmission method for transmitting packet data of a plurality of flows including a flow of a guaranteed bandwidth type and a flow of a best effort type. The packet data is classified for each flow to which the packet data belongs, and the classified packet data is controlled so as to be output in the order of input for each flow, and the transmission timing of the packet data belonging to the band-guaranteed flow is set to Determined in consideration of the guaranteed bandwidth, determined to transmit the packet data of the best effort type flow at a transmission timing that does not transmit the packet data belonging to the bandwidth guaranteed type flow, the packet data of the flow, The transmission is performed at the determined transmission timing in the order of output based on the control.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A communication system according to an embodiment of the present invention will be described below. First Embodiment FIG. 1 is an overall configuration diagram of a communication system 20 according to the present embodiment. As shown in FIG. 1, the communication system 20 includes a network 10 ₁ and 10 ₂ via the relay device 22 is connected, the transmission device 21 ₁ and the receiving apparatus 23 to the network 10 ₁ is connected, the network 10 ₂ transmitting device 21 ₂ is connected to. Note that the configuration of the communication system 20 shown in FIG. 1 is an example, and the number and configuration of networks and the number of transmitting devices and receiving devices connected to the networks are arbitrary. Here, the transmitting device 21
_1, 21 ₂ and the relay device 22 corresponds to the transmitter of the present invention, the receiving device 23 corresponds to the receiving apparatus of the present invention.

Hereinafter, each component of the communication system 20 will be described. [Network 10 ₁ , 10 ₂ ] Network 10 ₁ ,
102 ₂ is a LAN (Local) that can perform communication using variable-length packet data and guarantee the band of the communication.
Area Network) or a communication network such as the Internet.

[Transmission devices 21 ₁ and 21 ₂ ] Transmission device 21
_1, 21 ₂ transmits the data as packet data, for example, a server apparatus or a personal computer. FIG. 2 is a functional block diagram of the transmitting devices 21 ₁ and 21 ₂ . As shown in FIG. 2, the transmitting devices 21 ₁ and 21 _1
2 is, for example, a storage unit 30, a packet input unit 31, a packet queue management unit 32, a flow management unit 33, a timer 3
4. Transmission timing determination unit 35 and packet transmission unit 3
6. Here, the packet queue management unit 32 corresponds to the input / output control unit of the present invention, and the transmission timing determination unit 3
5 corresponds to the transmission timing determining means of the present invention, and the packet transmitting section 36 corresponds to the transmitting means of the present invention.

The storage unit 30 stores one or more systems of content data, and stores the content data in FIG.
The packet data is generated by adding the packet header shown in FIG. 3 and packetizing the packet data, and outputting the packet data to the packet input unit 31. Note that packet data may be generated using content data supplied from a unit other than the storage unit 30.

The packet input unit 31 converts the packet data input from the storage unit 30 for each flow on the basis of the information of each flow managed by the flow management unit 33 described later, using the identifier in the packet header. The packet queue management unit 3 classifies and packet data belonging to the same flow.
2 to the same packet queue.

The packet queue management section 32 has a plurality of packet queues, and stores packet data input from the packet input section 31 in a designated packet queue. Each packet queue of the packet queue management unit 32 outputs the stored packet queue in the order of input. In the present embodiment, the packet queue management unit 32
For example, as shown in FIG. 2, packet queues Qa _{1 to} Qa ₁ for storing packet data of a band-guaranteed flow.
₁₀ and a packet queue Qb for storing packet data of a best effort type flow.

The flow management unit 33 manages conditions for guaranteeing the bandwidth required for each flow to which the packet data belongs.

The timer 34 counts a time (time information of the present invention) serving as a reference for defining the transmission timing of packet data. As described later, the timer 34
When n is an integer satisfying 1 ≦ n ≦ 10, a time t at which the transmission timing determining unit 35 performs scheduling
based on the _current, time C _n until such time that it needs to send the packet data stored in the head of the packet queue Qa _n of the packet queue management unit 32 for performing bandwidth guarantee flow F _n band-guaranteed (Time information of the present invention). In the present embodiment, the time C _n is used only when scheduling is performed by the transmission timing determination unit 35 after transmission of packet data, and the packet data transmission interval of each flow F _n is known in advance from the band of the flow. Has been
Lixia Zhang, VirtualClock: A New Traffic Control Al
gorithm for Packet Switcing Network, ACMSIGCOMM '90
Using the method described in Sep 1990, the time is counted (generated) by one timer, and the time C _n is calculated using the transmission time of the packet data and the transmission interval of each flow.
get _n . Instead of the timer 34 may be used a few minutes of the timer of the flow F _n of bandwidth guaranteed to count each time C _n.

The transmission timing determining unit 35 controls the packet queue managing unit 3 based on the control from the flow managing unit 33.
The transmission timing of packets stored in the plurality of packet queues is scheduled (determined), and the packet transmission unit 36 is instructed on the basis of the determined schedule to transmit packet data. In addition, when it is necessary to transmit packets of a plurality of bandwidth-guaranteed flows at the same transmission timing in order to perform bandwidth guarantee of a bandwidth-guaranteed flow, the transmission timing determination unit 35 performs the transmission according to a predetermined algorithm. One of the bandwidth-guaranteed flows is selected from the bandwidth-guaranteed flows, and it is determined that the packet data of the selected flow is transmitted at the transmission timing. The algorithm includes, for example, (1) preferentially transmitting packet data having a small packet size, (2) packet data having the earliest time input to the packet queue (packet data that has not been output for the longest time). Priority transmission (3)
Give each packet queue a fixed priority (for example,
(Determining according to the characteristics of the flow at the time of reservation, or simply performing random ordering), or (4) using the number and ratio of priority given to the same situation in the past.

FIG. 3 is a diagram for explaining the scheduling processing of the transmission timing of the packet data in the transmission timing determining section 35. The transmission timing determination unit 35 performs the scheduling process each time a packet is transmitted from the packet transmission unit 36.

In FIG. 3, C _n is defined as 1 ≦ n
When set to an integer satisfying ≦ 10, transmission timing determination unit 35 based on the time t _current for scheduling, in order to perform bandwidth guarantee flow F _n, the head of the packet queue Qa _n of the packet queue management unit 32 Shows the time up to the time when the packet data stored in.

Step ST1: Transmission timing decision unit 3
5 is all the flows F of the guaranteed_n About the bandwidth protection
Flow F_n Next packet data
To the time t_current Deduct
Time C_n And the minimum time C _n Identify
I do.

Step ST2: Transmission timing decision unit 3
5, by the specified time C _n is equal to or less than a zero in step ST1, the process proceeds to step ST5 when it is determined to be less than or equal to zero.

Step ST3: Transmission timing decision unit 3
No. 5 determines whether or not packet data is stored in the packet queue Qb storing the packet data of the best effort type flow. If it is determined that the packet data is not stored, the process returns to step ST2 to store the packet data. If it is determined that it has been performed, the process proceeds to step ST4.

Step ST4: Transmission timing decision unit 3
5 instructs the packet transmitting unit 36 to transmit the head packet data of the packet queue Qb storing the packet data of the best effort type flow.

Step ST5: Transmission timing decision unit 3
5 is the packet queue Qa of the packet queue management unit 32
_n top packet size of the packet data stored in the calculated time R _n is divided by the reserved bandwidth of the flow F _n.

The transmission timing determining unit 35 instructs the packet transmitting unit 36 to transmit the first packet data of the packet queue Qb storing the packet data of the best effort type flow.

The transmission timing determining unit 35 determines in step S
Time R calculated in T5_n And time C _n Is added to the
New result C_n And

The packet transmitting section 36 reads out the packet queue from the packet queue of the packet queue managing section 32 based on the instruction from the transmission timing determining section 35,
The read packet data is transmitted to the network 10 ₁ in the case of the transmitting device 21 ₁ , and is transmitted to the network 10 ₂ in the case of the transmitting device 21 ₂ . At this time, as shown in FIG. 4, the packet transmission unit 36 determines that the control unit 40 transmits the transmission timings of the packet queues Qa _{1 to} Qa ₁₀ and the top packet queue of Qb based on the instruction from the transmission timing determination unit 35. Is determined based on the above-described times C _{1 to} C ₁₀ .

Hereinafter, an operation example of the transmission devices 21 ₁ and 21 ₂ will be described. Best In First operation example] In this operation example, the processing of step ST4 in the processing of the transmission timing determination unit 35 shown in FIG. 3 is executed, stored from the transmitting apparatus 21 _1, 21 ₂ at the head of the packet queue Qb A case where packet data of an effort type flow is transmitted will be described. In the operation example, there are _four flows F ₁ , F ₂ , F ₃ , and F ₄ as the bandwidth guaranteed flows F _n .

[0041] Figure 5, in this example of operation, a packet data flow F _n of guaranteed-bandwidth (packet queues Qa _n
FIG. 9 is a diagram for explaining scheduling of transmission timing of (the first packet data). In FIG. 5, the horizontal axis indicates time. As shown in FIG. 5, in the present operational example, flow F ₁ of the band-guaranteed, F _2, F _3, the time C ₁ for _{F 4, C 2, C 3} , C 4 are all positive. Further, packet data is stored in the packet queue Qb of the best effort type flow, and the packet transmission unit 36
Packet data flow of best effort stored in the head of the packet queue Qb are transmitted over the network 10 ₁ or 10 ₂ is read from.

[Second Operation Example] In this operation example, in the processing of the transmission timing determination unit 35 shown in FIG.
Process T6 is performed, the packet data of the flow of the stored bandwidth guaranteed to the beginning of the transmission device 21 _1, 21 ₂ from the packet queue Qa _n will be described when it is transmitted. In the operation example, there are _four flows F ₁ , F ₂ , F ₃ , and F ₄ as the bandwidth guaranteed flows F _n .

For example, as shown in FIG. 6, when the packet data transmission timing is scheduled so that the bandwidth guaranteed flows F ₃ and F ₄ have the same transmission timing, the transmission timing determination unit 35 According to a predetermined algorithm, for example, packet queue Q
and instructs the packet transmitting unit 36 to transmit the packet data flow F ₃ stored in a _3, when the packet transmission unit 36 then performs scheduling, as shown in FIG. 7, the packet queue Qa ₄ Time t ₁ at which the stored packet data of flow F ₄ is to be transmitted is time t ₁
Before _current . That is, the time C _{4 of} the bandwidth guaranteed type flow F ₄ becomes negative, and the transmission timing determination unit 35 performs the processing of steps ST5, ST6, and ST7 shown in FIG.
Packet head on the stored bandwidth-guaranteed flow of packet data queue Qa ₄ is read out and network 1
0 is transmitted over a ₁ or 10 _2.

[0044] [repeater 22] relay device 22, in the example shown in FIG. 1, via the network 10 ₂ 21
₂ relays the packet received from network 10
_The data is transmitted to the receiving device 23 via ₁ and is, for example, a router. FIG. 8 is a functional block diagram of the relay device 22.
As illustrated in FIG. 8, the relay device 22 includes, for example, a packet receiving unit 51, a packet queue managing unit 32, a flow managing unit 33, a timer 34, a transmission timing determining unit 35, and a packet transmitting unit 36. The packet queue management unit 32, the flow management unit 33, the timer 34, the transmission timing determination unit 35, and the packet transmission unit 36 illustrated in FIG. 8 are the same as those described in the first embodiment.

The packet receiving unit 51 is connected to the network 10
_The packet data received from the transmission device 212 via the communication device ₂ is classified for each flow using the identifier in the packet header, and the packet data belonging to the same flow is output to the same packet queue of the packet queue management unit 32.

The processing of the relay device 22 is performed by the packet receiving unit 5
1 except that receives a packet from the network 10 ₂ is the same as the transmitting apparatus 21 _1, 21 ₂ described above.

[0047] [receiving apparatus 23] receiving device 23, for example, a terminal device such as a personal computer, the packet data received via the network 10 ₁ to unpacketization generates content data, use the content data Perform the processing that was performed.

Hereinafter, an example of the entire operation of the communication system 1 shown in FIG. 1 will be described. In the operation example, the transmitting device 21 ₂
A case where packet data is transmitted to the receiving device 23 from the first embodiment will be described. For example, the transmission device 21 _2, through the processing described operation example described above, the packet data of a plurality of flows (content data) is transmitted to the relay device 22 via the network 10 _2. Next, the relay device 22 receives the packet data of the plurality of flows,
The packet data is transmitted to the receiving apparatus 23 via the network 10 ₁ through the process described above. Then, in the receiving apparatus 23, the packet data received via the network 10 ₁ is in the content data is generated unpacketizing, processing using the content data.

As described above, according to the communication system 1, when packet data of a band-guaranteed flow and packet data of a best-effort flow are transmitted via the same networks 10 ₁ and 10 _2. , the transmission device 21 _1, 21 ₂ and the relay device 22 without large-scale and complicated, with the packet data flow for best-effort can be transmitted stably, it is possible to reduce the influence on the flow of the bandwidth-guaranteed . That is, in the transmitting apparatus 21 _1, 21 ₂ and the relay device 22, has been conventionally used, the time up to the time it needs to send the packet data stored in the head of the packet queue Qa _n of the packet queue management unit 32 using the C _n, only by performing the processing shown in FIG. 3 at the transmission timing determination unit 35 shown in FIGS. 2 and 8, a good balance transmits the packet data with the flow of bandwidth guaranteed and best effort flows it can. For example, as shown in FIG. 9, the transmission devices 21 ₁ and 21 ₂ and the relay device 22 schedule transmission of packet data of a band-guaranteed flow even when the transmission of packet data of the band-guaranteed flow is affected. If it is before the time, the packet data of the best effort type flow is transmitted. As a result, the bandwidth guarantee of the bandwidth guaranteed type flow is lost, but if the time is before the scheduled transmission time of the packet data, the effect can be reduced.

The present invention is not limited to the above embodiment. In the present invention, for example, the packet queue management unit 132 shown in FIG. 10 may be used as the packet queue management unit 32 shown in FIG. 2 and FIG. As shown in FIG. 10, the packet queue management unit 132
The same reference numerals as packet queue Qa ₁ ~Qa ₁₀ for storing packet data flow guaranteed bandwidth marked with, in addition to the packet queue Qb for storing packet data of best effort flows, best effort flows and Packet queues Qb _1-
Further comprising a Qb _5. Packet queue Qb ₁ ~Qb ₅
Are provided before the packet queue Qb, and the packet queues Q in the order in which the corresponding best-effort flow packet data are input from the packet input unit 31.
b. As a result, it is possible to handle a best effort type flow of a plurality of systems.

In the above-described embodiment, the case where variable-length packet data is transmitted has been described as an example. However, the present invention can be applied to the case where fixed-length packet data is transmitted.

[0052]

As described above, according to the present invention,
When transmitting packet data of a bandwidth-guaranteed flow and packet data of a best-effort flow through the same communication network, a relatively small and simple configuration is used.
A transmission device, a communication system, and a transmission method that can appropriately avoid a situation in which packet data of a best-effort flow is not transmitted at all can be provided. Further, according to the present invention, it is possible to provide a transmission device, a communication system, and a transmission method capable of reducing the influence of transmission of packet data of a best effort type flow on a bandwidth guaranteed type flow.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a communication system according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of a transmission device shown in FIG. 1;

FIG. 3 is a flowchart for explaining a scheduling process of packet data transmission timing in a transmission timing determining unit;

FIG. 4 is a diagram for explaining a packet transmission unit.

FIG. 5 illustrates a case where the process of step ST4 is executed in the process of the transmission timing determining unit, and packet data of a best effort type flow stored at the head of the packet queue Qb is transmitted from the transmitting device. FIG.

Figure 6 is the processing of step ST5 in the process of the transmission timing determination unit shown in FIG. 3 is executed, the packet data flow guaranteed bandwidth stored in the head of the packet queue Qa _n from the transmission apparatus transmits It is a figure for explaining the case where it is performed.

Figure 7, the processing of step ST5 in the process of the transmission timing determination unit shown in FIG. 3 is executed, the packet data flow guaranteed bandwidth stored in the head of the packet queue Qa _n from the transmission apparatus transmits It is a figure for explaining the case where it is performed.

FIG. 8 is a functional block diagram of the relay device shown in FIG. 1;

FIG. 9 is a diagram illustrating an example of packet data transmission in the communication system according to the present embodiment.

FIG. 10 is a diagram for explaining a modification of the packet queue management unit shown in FIGS. 2 and 8;

FIG. 11 is an overall configuration diagram of a conventional communication system.

FIG. 12 is a diagram for explaining a packet data transmission method of a conventional communication system transmission device and a relay device.

FIG. 13 is a diagram for explaining the configuration of a header of packet data.

FIG. 14 is a diagram for explaining scheduling of packet data transmission timing of a bandwidth guaranteed type flow in the conventional communication system shown in FIG. 11;

FIG. 15 is a diagram for explaining transmission timing of packet data scheduled at the same timing in the case shown in FIG. 14;

FIG. 16 is a diagram for explaining the transmission timing of the best-effort packet data in the conventional communication system shown in FIG. 11;

FIG. 17 is a diagram for explaining a problem of the conventional communication system shown in FIG. 11;

[Explanation of symbols]

1: Communication system, 21 ₁ , 21 ₂ : Transmitting device, 22:
Relay device, 23 receiving device, 30 storage unit, 31 packet input unit, 32 packet queue management unit, 33 flow management unit, 34 timer, 35 transmission timing decision unit, 36 packet transmission unit, 51 ... Packet receiving unit, Q
packet queue for storing a ₁ ~Qa ₁₀ ... packet queue for storing packet data flow guaranteed bandwidth, Qb, a packet data flow Qb ₁ ~Qb ₅ ... Best Effort

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K030 HA08 KA03 KA21 KX29 LC01 LC08 5K034 EE11 HH01 HH21 HH65 JJ23 MM11 MM22

Claims (14)

[Claims] 1. A transmitting apparatus for transmitting packet data of a plurality of flows including a bandwidth-guaranteed flow and a best-effort flow, wherein the transmitting apparatus transmits input packet data to each of the flows to which the packet data belongs. An input / output control unit that classifies and outputs the classified packet data in order of input for each flow, and determines a transmission timing of the packet data belonging to the band-guaranteed type flow in consideration of a guaranteed band of the flow. Transmission timing decision means for deciding to transmit the packet data of the best effort type flow at a transmission timing not transmitting the packet data belonging to the bandwidth guaranteed type flow; Transmitting means for transmitting at the determined transmission timing in the order of output from the control means Transmitting device having a. 2. The transmission timing determining means according to a predetermined priority, when it is necessary to transmit a plurality of packets of the band guarantee type flow at the same transmission timing in order to perform the band guarantee. The transmission device according to claim 1, wherein one of the band-guaranteed flows is selected from a plurality of the band-guaranteed flows, and it is determined that the packet data of the selected flow is transmitted at the transmission timing. 3. The transmission timing determining means has a timer for generating time information used to determine the timing of transmitting the packet data, and the time information is determined for each of the bandwidth guaranteed flows. From the indicated time, time information indicating a time obtained by subtracting the time when the packet data belonging to the flow is determined to be transmitted next is generated, and based on the time information, the packet data belonging to the band-guaranteed flow is generated. The transmission device according to claim 1, wherein a transmission timing at which packet data is not transmitted is specified. 4. The transmission timing determining means determines that the packet data of the best effort type flow is transmitted when the time information of all the bandwidth guaranteed type flows indicates a positive value. The transmitting device according to claim 3, wherein 5. The transmission timing determining means, using the bandwidth allocated to the flow and the data amount of packet data transmitted in the flow, when transmitting the packet data belonging to the flow next time The transmission device according to claim 3, wherein the transmission device determines: 6. The transmission timing determination means according to claim 1, wherein said transmission timing determination means includes a plurality of timers provided corresponding to each of said flows, and defining a next transmission time of said packet data belonging to the corresponding flow. Transmission device. 7. The transmitting apparatus according to claim 1, wherein said packet data length is variable. 8. A communication system comprising: a receiving device; and a transmitting device that transmits packet data of a plurality of flows including a guaranteed bandwidth flow and a best effort flow to the receiving device via a communication line. The transmitting device classifies the input packet data for each flow to which the packet data belongs, and an input / output control unit that outputs the classified packet data in order of input for each flow, The transmission timing of the packet data belonging to the flow is determined in consideration of the guaranteed bandwidth of the flow, and the packet data of the best-effort flow is transmitted at a transmission timing at which the packet data belonging to the bandwidth-guaranteed flow is not transmitted. Transmission timing determining means for deciding to perform packet data of the flow, Sequentially outputted from the output control means, a communication system having a transmitting means for transmitting at a transmission timing said determined. 9. A transmission method for transmitting packet data of a plurality of flows including a guaranteed bandwidth type flow and a best effort type flow, wherein the input packet data is transmitted for each of the flows to which the packet data belongs. Classify, control to output the classified packet data for each flow in the order of input, determine the transmission timing of the packet data belonging to the bandwidth guaranteed type flow in consideration of the guaranteed bandwidth of the flow, It decides to transmit the packet data of the best effort type flow at a transmission timing not transmitting the packet data belonging to the bandwidth guaranteed type flow, and the packet data of the flow is output in an order based on the control. A transmission method for transmitting at the determined transmission timing. 10. When a plurality of packets of the bandwidth guarantee type flow need to be transmitted at the same transmission timing in order to perform the bandwidth guarantee, the plurality of bandwidth guarantee type flows are determined based on a predetermined priority. The transmission method according to claim 9, wherein one of the bandwidth-guaranteed flows is selected from the flows, and it is determined that the packet data of the selected flow is transmitted at the transmission timing. 11. Time information used to determine a timing of transmitting the packet data is generated, and for each of the bandwidth guaranteed flows, the packet data belonging to the flow from the time indicated by the time information. A request for generating time information indicating a time obtained by subtracting a time when it is determined that the packet data is transmitted next, and specifying a transmission timing at which the packet data belonging to the band-guaranteed flow is not transmitted, based on the time information. Item 10. The transmission method according to Item 9. 12. The method according to claim 11, wherein when the time information of all the bandwidth guaranteed flows indicates a positive value, it is determined to transmit the packet data of the best effort flow. Transmission method. 13. The method according to claim 11, wherein a next transmission time of the packet data belonging to the flow is determined by using a band allocated to the flow and a data amount of packet data transmitted in the flow. The transmission method described. 14. The transmission method according to claim 9, wherein said packet data data length is variable.