JP2002135320A - Transmitter, communication system and transmission method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmitter that can efficiently transmit packet data of a band warrant type flow and packet data of a best effort type flow via the same communication network. SOLUTION: The transmitter is provided with a flow management section 33 that assigns a prescribed communication bandwidth to the band warrant type flow and the best effort type flow, a transmission timing decision section 35 that takes band warrant of communication using the assigned communication bandwidth into account to decide transmission timing of the packet data of the band warrant type flow and the best effort type flow, and a packet transmission section 36 that sequentially transmits the packet data of the band warrant type flow in the order outputted from queues Qa1-Qa10 and sequentially transmits the packet data of the best effort type flow in the order outputted from a queues Qb in the decided transmission timing.

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. 14, 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 15 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 scheduled in advance, for example. 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, the transmission device 11 _1, 11 ₂ and the relay device 12, as shown in FIG. 16, the queue Qa
Consider the case where the schedule when transmitting a first packet data of _{1 ~Qa 10.} In this case is the transmission of the first packet in the queue Qa ₃ and Qa ₁₀ at time t ₁ is conflict, according to a predetermined algorithm, for example, the transmission of the first packet in the queue Qa ₁₀ is selected. Then, as shown in FIG. 17, is performed anew scheduling, the first packet in the queue Qa ₃ is sent at time t _2. Thereafter, as shown in FIG. 17, for possible conflicts, the transmission of the first packet in the queue Qa ₁ at time t _3, the transmission of the first packet in the queue Qa ₁₀ at time t _5, the queue at time t ₆ the transmission of the first packet of Qa _1, the transmission of the packet at the head of the queue Qa ₂ at time t _7,
The transmission of the packet at the head of the queue Qa ₃ at time t ₈ is performed in the order. 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. 18, 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 of 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 that transmits packet data of a plurality of flows using a predetermined communication bandwidth, including:
First input / output control means for outputting the input packet data of the guaranteed bandwidth type flow in the order of input; second input / output control means for outputting the input packet data of the best effort type flow in the input order; A flow management unit for allocating the predetermined communication bandwidth to the band-guaranteed flow and the best-effort flow; and considering the band guarantee of communication using the allocated communication bandwidth, the band-guaranteed type Timing determining means for determining the transmission timing of the packet data of the best effort flow and the best effort flow, and the first input / output control of the packet data of the bandwidth guaranteed flow at the determined transmission timing. Means for transmitting the packet data of the best-effort flow in the second ingress / egress direction. And a transmitting means for transmitting the order to be outputted from the control means.

The operation of the transmitting apparatus according to the first invention is as follows. A predetermined communication bandwidth of the transmitting apparatus is assigned to the band-guaranteed type flow and the best-effort type flow by the flow management unit, and communication using the allocated communication bandwidth is set by the transmission timing determining unit. In consideration of the bandwidth guarantee, the transmission timing of the packet data of the bandwidth guaranteed type flow and the best effort type flow is determined. Then, at the determined transmission timing, the packet data of the bandwidth-guaranteed flow is transmitted by the transmission unit in the order in which the packet data is output from the first input / output control unit, and the packet of the best-effort flow is transmitted. Data is transmitted in the order in which the data is output from the second input / output control means.

[0013] In the transmission apparatus according to the first invention, preferably, the flow management means allocates a communication bandwidth required for bandwidth guarantee to the bandwidth-guaranteed flow from the predetermined communication bandwidth. , And allocate the remaining communication bandwidth to the best effort type flow.

[0014] In the transmission apparatus of the first invention, preferably, the transmission timing determining means sets a first time which is a time until transmission timing of next transmission of packet data of the bandwidth guaranteed type flow. Calculating a second time which is a transmission time required to transmit packet data to be output next from the second input / output control means;
When the time is shorter than the first time, it is determined that the packet data to be output next from the second input / output control means is transmitted.

[0015] In the transmission apparatus of the first invention, preferably, the transmission timing determining means is configured to transmit packets of the plurality of flows at the same transmission timing based on a predetermined priority. One flow is selected from the plurality of flows, and it is determined that the packet data of the selected flow is transmitted at the transmission timing.

Further, in the transmitting apparatus according to the first aspect of the present invention, preferably, the transmission timing determining means has a timer for generating time information used to determine a timing of transmitting the packet data; For each guaranteed flow, the first time is 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.

[0017] In the transmission apparatus according to the first invention, preferably, the transmission timing determining means determines a communication bandwidth allocated to the best effort type flow and a second bandwidth from the second input / output control means. The second time is obtained by using the packet size of the output packet data.

In the transmission device 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.

In the transmitting apparatus according to the first invention, preferably, at least one of the first input / output control means and the second input / output control means transmits packet data of the input flow, The packet data is classified for each flow to which the packet data belongs, and the classified packet data is output for each flow in the order of input.

[0020] In the transmission device of the first invention, preferably, the packet data length is variable.

The communication system according to a second aspect of the present invention transmits packet data of a plurality of flows including a band-guaranteed flow and a best-effort flow to a receiving device and the receiving device via a communication line. A communication system comprising: a transmission device, the transmission device comprising: a first input / output control unit configured to output, in an input order, packet data of an input bandwidth-guaranteed flow; Second input / output control means for outputting packet data in the order of input, flow management means for allocating the predetermined communication bandwidth to the band-guaranteed flow and the best-effort flow, and the allocated communication bandwidth The packet data of the bandwidth-guaranteed flow and the best-effort flow in consideration of the bandwidth guarantee of communication using A transmission timing determining means for determining a transmission timing at the transmission timing at which the determined,
The packet data of the bandwidth guaranteed type flow is transmitted in the order output from the first input / output control means, and the packet data of the best effort type flow is transmitted in the order output from the second input / output control means. And transmission means for transmitting.

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 guaranteed bandwidth type flow and a best effort type flow using a predetermined communication bandwidth. , Output the input packet data of the guaranteed bandwidth type flow in the order of input for each flow,
The input packet data of the best effort type flow is output in the input order, the predetermined communication bandwidth is allocated to the bandwidth guaranteed type flow and the best effort type flow, and the allocated communication bandwidth is used. In consideration of the bandwidth guarantee of communication, a transmission timing of the packet data of the flow of the bandwidth guarantee type and the flow of the best effort type is determined, and the packet data of the flow of the bandwidth guarantee type is determined at the determined transmission timing. Are transmitted in the output order, and the packet data of the best effort type flow is transmitted in the output order.

[0023]

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 22 correspond to the transmitting device of the present invention, and the receiving device 23 corresponds to the receiving device 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 queues Qa _{1 to} Qa ₁₀ of the packet queue management unit 32 correspond to the first input / output control unit of the present invention, and the packet queue Qb corresponds to the second input / output control unit of the present invention. The management unit 33 corresponds to the flow management unit of the invention, the transmission timing determination unit 35 corresponds to the transmission timing determination unit of the invention, and the packet transmission unit 36 corresponds to the transmission unit of the invention. Transmission device 2
1 _1, 21 _2, for example, has a total communications bandwidth W in the transmission of packet data.

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. 5 and packetizing the packet data, and outputting the packet data to the packet input unit 31.

The packet input unit 31 includes a flow management unit 33
, The packet data input from the storage unit 30 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 packet queue management unit 32 has a plurality of packet queues, and stores packet data input from the packet input unit 31 into 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 allocates a communication bandwidth to the flow based on a band guarantee condition required for the band-guaranteed type flow, and transmits the transmission devices 21 ₁ and 21 2.
Assigning the remaining communication bandwidth after allocating the flow of guaranteed bandwidth of 2 ₂ total communications bandwidth W to best effort flows. In the present embodiment, the flow management unit 33
For example, as shown in FIG. 3, allocates a communication bandwidth Wa ₁ ~Wa ₁₀ respectively flow Fa ₁ ~Fa ₁₀ band-guaranteed among all communications bandwidth W, the best effort and the remaining communication band width Wb Is assigned to the type flow Fb.

The timer 34 counts a reference time (time information of the present invention) for defining the transmission timing of the 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, the flow Fa _n, packet queue Qa packet queue management unit 32 for performing bandwidth guarantee of Fb _n, Time Ca _n until such time that it needs to transmit the packet data stored in the head of the Qb , Cb (time information of the present invention). In the present embodiment, the times Ca _n and Cb are used only when scheduling is performed by the transmission timing determination unit 35 after the transmission of the packet data, and the respective flows Fa _n and Fb are used.
Since the transmission interval of the packet data b is known in advance from the band of the flow, Lixia Zhang, VirtualClock: A
New Traffic Control Algorithm for Packet Switcing N
Etwork, using the procedures described in ACM SIGCOMM '90 Sep 1990, counts the time with one timer (generation), the time Ca _n, the transmission time of the packet data Cb, and a transmission interval for each flow To obtain the time C _n . Instead of the timer 34, the flow Fa _n that counts time Ca _n, Cb, respectively, may be used a few minutes of the timer of Fb.

The transmission timing determining unit 35 controls the packet queue managing unit 3 based on the control from the flow managing unit 33.
The packet transmission unit 36 schedules (determines) the transmission timing of the packets stored in the plurality of packet queues, and instructs the packet transmission unit 36 on the packet data transmission timing based on the determined schedule. In addition, when it is necessary to transmit packets of a plurality of bandwidth-guaranteed flows at the same transmission timing in order to guarantee the bandwidth of each flow, the transmission timing determination unit 35, in accordance with a predetermined algorithm, The algorithm for selecting one band-guaranteed flow from the guaranteed flow and determining to transmit the packet data of the selected flow at the transmission timing is, for example, (1) small packet size Send packet data with priority,
(2) Packet data with the earliest time input to the packet queue (packet data that has not been output for the longest time) is transmitted preferentially. (3) Each packet queue has a fixed priority (for example, (Determined according to the characteristics of the flow at the time of reservation, or simply performing random ordering), or (4) using the number or ratio of priority given to the same situation in the past.

The transmission timing determining unit 35 performs the scheduling process every time a packet is transmitted from the packet transmitting unit 36. Hereinafter, first to third examples of the scheduling process performed by the transmission timing determining unit 35 will be described. <First Example> FIG. 4 is a flowchart for explaining a first example of the scheduling process performed by the transmission timing determining unit 35. In the first example, the transmission timing determination unit 35 treats these flows equally to ensure that the bandwidths allocated to the bandwidth-guaranteed flow and the best-effort flow are as equal as possible. Determine the timing.

Step ST1: Transmission timing decision unit 3
5, all the flows Fa _n band-guaranteed and best-effort, the Fb, minus the time t _current from the Fa _n, the time that must be sent to the next packet data Fb to perform bandwidth guarantee time Ca _n,
To obtain Cb, or identify the minimum time among the Ca _n or Cb.

Step ST2: Transmission timing decision unit 3
5, step when the minimum time Ca _n or Cb identified in step ST1, it is determined whether a 0 or less, the flow proceeds to the processing in step ST1 if it is determined that less than or equal to zero, otherwise The process returns to ST1.

Step ST3: Transmission timing decision unit 3
5 instructs the packet queue Qa _n corresponding to the minimum time specified in step ST1 Ca _n or Cb, and transmitting a first packet data Qb to the packet transmission unit 36.

[0036] Step ST4: assigned minimum packet size of the packet data stored in the beginning of the time Ca _n or packet queue Qa _n or Qb corresponding to Cb identified in step ST1, the corresponding flow Fa _n or Fb communication bandwidth Wa _n or time divided by Wb R
Is calculated.

Step ST5: Transmission timing decision unit 3
5, the time R calculated in step ST4 is calculated in step S4.
It was added to the minimum time Ca _n or Cb specified in T1, the result of the addition as new time Ca _n or Cb.

As described above, according to the first operation example, the transmission timing determining unit 35 ensures that the bandwidths allocated to the bandwidth guaranteed type flow and the best effort type flow are guaranteed as much as possible. Therefore, the packet queue of the best-effort type flow can be reliably transmitted because it is instructed to transmit the packet data by treating the same flow as the same.

<Second Example> FIGS. 5 and 6 are flowcharts for explaining a second example of the scheduling process performed by the transmission timing determining unit 35. In the second example, the transmission timing determination unit 35 treats these flows equally to ensure that the bandwidths allocated to the band-guaranteed type flow and the best-effort type flow are as equal as possible. The timing is determined, and an instruction is made to transmit the packet data of the best-effort flow within a range that does not affect the bandwidth-guaranteed flow during a period in which the packet data of the bandwidth-guaranteed flow is not transmitted.

Step ST11: The transmission timing decision unit 35 needs to transmit the packet data of the relevant Fa _n and Fb next time in order to guarantee the bandwidth for all the bandwidth guaranteed and best effort type flows Fa _n and Fb. The time Ca obtained by subtracting the time t _current from a certain time Ca
_n, to obtain Cb, minimum time among the Ca _n or Cb
To identify.

[0041] Step ST12: transmission timing determination unit 35, the minimum time Ca _n identified in step ST11
Alternatively, it is determined whether or not Cb is 0 or less, and if it is determined that it is 0 or less, the process proceeds to step ST11, and if not, the process proceeds to step ST16.

[0042] Step ST13: transmission timing determination unit 35, the minimum time Ca _n identified in step ST11
Or packet queue Qa _n corresponding to Cb, the packet transmitting unit 36 to transmit the first packet data Qb
To instruct.

[0043] Step ST14: assigned the smallest packet size of the packet data stored in the beginning of the time Ca _n or packet queue Qa _n or Qb corresponding to Cb identified in step ST11, the corresponding flow Fa _n or Fb by dividing the communication speed when using the communication bandwidth Wa _n or Wb calculates the time R was.

[0044] Step ST15: transmission timing determination unit 35, the time R calculated in step ST14, adds the minimum time identified Ca _n or Cb in step ST1, and the addition result new time Ca _n or Cb I do.

Step ST16: The transmission timing determination unit 35 determines the time L required to transmit the head packet data of the packet queue Qb of the best effort type flow using the entire communication bandwidth W. The packet size of the packet data is divided by the communication speed when the entire communication bandwidth W is used.

[0046] Step ST17: transmission timing determination unit 35, the step if the time L obtained in step ST16 is to determine the minimum Ca _n or Cb is smaller than or not specified in step ST11, determines that the small ST
Proceeds to the process of step 18; otherwise, step ST1
It returns to the process of 1.

Step ST18: The transmission timing decision unit 35 instructs the packet transmission unit 36 to transmit the head packet data of the packet queue Qb.

Step ST19: The transmission timing decision unit 35 divides the packet size of the packet data stored at the head of the packet queue Qb by the communication speed when using the communication bandwidth Wb allocated to the flow Fb. The time R is calculated.

Step ST20: The transmission timing determining section 35 determines the time R calculated in step ST19 as
b, and the result of the addition is set as a new time Cb.

As described above, according to the second operation example, the transmission timing determination unit 35 ensures that the bandwidths allocated to the bandwidth guaranteed type flow and the best effort type flow are guaranteed as much as possible. Therefore, the packet queue of the best-effort type flow can be reliably transmitted because it is instructed to transmit the packet data by treating the same flow as the same. Further, according to the second operation example, the best effort type flow is not affected during the period in which the packet data of the bandwidth guaranteed type flow and the best effort type flow are not transmitted, on the condition that the flow is not affected. Since packet data of a flow can be transmitted, by allocating a bandwidth to a best-effort flow, transmission of packet data of a best-effort flow can be prevented from being limited to the bandwidth. The transmission timing determination unit 35 is configured, for example, as shown in FIG.
As shown in (A) to (E), the bandwidth is guaranteed.
Packet queues Qa _{1 to} Qa _{4 of} bandwidth guaranteed type flows
And the packet queue Qb of the best-effort flow
When the transmission timing of the first packet data is scheduled, there is no packet data to be transmitted at time t ₀ , and there is sufficient time to transmit the packet data to be transmitted next from the packet queue Qb. as shown in FIG. 7 (F), instructs the packet transmitting unit 36 to transmit the packet data of best effort flows at time t _0.

<Third Example> FIGS. 8 and 9 are flowcharts for explaining a third example of the scheduling process performed by the transmission timing determining unit 35. The third example is a modification of the second example described above. In packet data transmission, a bandwidth-guaranteed flow has a higher priority than a best-effort flow.

[0052] Step ST31: transmission timing determination unit 35 for all the bandwidth-guaranteed flows Fa _n, the time t _current from the Fa _n times that need to be sent to the next packet data to perform bandwidth guarantee subtracting time to obtain a Ca _n, specifies the minimum time among the Ca _n.

[0053] Step ST32: transmission timing determination unit 35, the minimum time Ca _n identified in step ST31
Is determined to be 0 or less, and if it is determined to be 0 or less, the process proceeds to step ST33; otherwise, the process proceeds to step ST36.

[0054] Step ST33: transmission timing determination unit 35, the minimum time Ca _n identified in step ST31
Sending a first packet data of the corresponding packet queue Qa _n to instruct the packet transmitting unit 36.

Step ST34: The steps ST31
Set minimum time Ca_n Packet queue Qa corresponding to
_n Packet size of packet data stored at the beginning of
To the corresponding flow Fa _n Communication bandwidth allocated to
Wa_n To calculate the time R.

[0056] Step ST35: transmission timing determination unit 35, the time R calculated in step ST34, adds the minimum time identified Ca _n in step ST31, the result of the addition as new time Ca _n.

Step ST36: The transmission timing determining unit 35 determines the time t from the time when the packet data of the best effort type flow Fb needs to be transmitted next time in order to guarantee the allocated bandwidth.
_The time Cb obtained by subtracting the _current is obtained, and the time C becomes 0
It is determined whether or not it is less than or equal to 0. If it is determined that it is 0 or less, the process proceeds to step ST39, and if not, the process proceeds to step ST37.

Step ST37: The transmission timing determination unit 35 determines the time L required to transmit the head packet data of the packet queue Qb of the best effort type flow using the entire communication bandwidth W. The packet size of the packet data is divided by the total communication bandwidth W.

[0059] Step ST38: transmission timing determination unit 35, time L obtained in step ST37 is to determine the minimum Ca _n smaller than or not specified in step ST31, if it is determined that the small step ST39 Proceed to the process, otherwise return to the process of step ST31.

Step ST39: The transmission timing determining unit 35 instructs the packet transmitting unit 36 to transmit the head packet data of the packet queue Qb.

Step ST40: The transmission timing decision unit 35 divides the packet size of the packet data stored at the head of the packet queue Qb by the communication speed when using the communication band Wb allocated to the flow Fb, and calculates the time. Calculate R.

Step ST41: The transmission timing determining unit 35 determines the time R calculated in step ST40 as the time C
b, and the result of the addition is set as a new time Cb.

The packet transmission unit 36 reads out packet data from the packet queue of the packet queue management unit 32 based on the instruction from the transmission timing determination unit 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. 10, 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 the 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 .

[0064] [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. 11 is a functional block diagram of the relay device 22. As illustrated in FIG. 11, 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 shown in FIG.
Transmission timing determination unit 35 and packet transmission unit 36
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.

[0067] [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 overall operation of the communication system 20 shown in FIG. 1 will be described. In the operation example, the transmitting device 21
_The case where packet data is transmitted from ₂ to the receiving device 23 will be exemplified. 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, in the relay device 22, the packet data of the plurality of flow is received, the packet data is transmitted to the receiving apparatus 23 via the network 10 ₁ through the process described above. next,
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 20, the packet data of the flow of the guaranteed bandwidth and the packet data of the best-effort flow are transmitted through 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 , the transmission timing determination unit 35 shown in FIGS. 2 and 11 only performs the processing shown in FIGS. 4, 5, 6, 8, and 9, and thus guarantees the bandwidth-guaranteed flow and best effort. It is possible to transmit packet data with a type flow in a well-balanced manner.

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. 12 may be used as the packet queue management unit 32 shown in FIG. 2 and FIG. As shown in FIG. 12, the packet queue management unit 132 includes packet queues Qa _{1 to} Qa ₁₀ for storing packet data of a band guarantee type flow denoted by the same reference numerals as those in FIGS. 2 and 11, and a best effort type flow. Packet queue Qb for storing the packet data of the best effort type flow in addition to the packet queue Qb for storing the packet data of
Further comprising a _{1 ~Qb 5.} Packet queues Qb ₁ -Q
b ₅ is provided in front of the packet queue Qb, and outputs the order of entry packet data of the flow of the corresponding best effort from the packet input unit 31 to the packet queue Qb. 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 exemplified. However, the present invention can be applied to the case where fixed-length packet data is transmitted.

[0072]

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, the packet data of the best-effort flow is relatively small and simple. A transmission device, a communication system, and a transmission method capable of appropriately avoiding a situation in which transmission cannot be performed 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 diagram for explaining band allocation to each flow by a flow management unit shown in FIG. 2;

FIG. 4 is a flowchart for explaining a first example of scheduling processing of packet data transmission timing in a transmission timing determination unit;

FIG. 5 is a flowchart illustrating a second example of a packet data transmission timing scheduling process performed by the transmission timing determining unit;

FIG. 6 is a flowchart for explaining a second example of the packet data transmission timing scheduling process in the transmission timing determination unit.

FIG. 7 is a diagram for explaining an example of transmission timing of a packet queue when the second example shown in FIG. 6 is used.

FIG. 8 is a flowchart for explaining a third example of the scheduling process of the transmission timing of the packet data in the transmission timing determining unit.

FIG. 9 is a flowchart for explaining a third example of the scheduling processing of the transmission timing of the packet data in the transmission timing determining unit.

FIG. 10 is a diagram for explaining a packet transmission unit.

FIG. 11 is a functional block diagram of the relay device shown in FIG. 1;

FIG. 12 is a diagram for explaining a modification of the packet queue management unit shown in FIGS. 2 and 11;

FIG. 13 is an overall configuration diagram of a conventional communication system.

FIG. 14 is a diagram for explaining a packet data transmission method of a conventional communication system transmission device and a relay device.

FIG. 15 is a diagram for explaining a configuration of a header of packet data;

FIG. 16 is a diagram for explaining scheduling of packet data transmission timing of a flow of a guaranteed bandwidth type in the conventional communication system shown in FIG. 13;

FIG. 17 is a diagram for explaining transmission timings of packet data scheduled at the same timing in the case shown in FIG. 16;

FIG. 18 is a diagram for explaining transmission timing of best-effort packet data in the conventional communication system shown in FIG.

FIG. 19 is a diagram for explaining a problem of the conventional communication system shown in FIG. 13;

[Explanation of symbols]

20 communication system, 21 ₁ , 21 ₂ transmission 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 determination 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

Claims (18)

[Claims] 1. A transmitting apparatus for transmitting packet data of a plurality of flows including a band-guaranteed flow and a best-effort flow using a predetermined communication bandwidth, wherein the input band-guaranteed flow is provided. First input / output control means for outputting the packet data of the best effort type flow, second input / output control means for outputting the input best effort type packet data in the input order, Flow management means for allocating to the bandwidth-guaranteed flow and the best-effort flow; considering the bandwidth guarantee of communication using the allocated communication bandwidth, the bandwidth-guaranteed flow and the best-effort flow A transmission timing determining means for determining a transmission timing of the packet data of the flow; and The packet data of the bandwidth guaranteed type flow is transmitted in the order output from the first input / output control means, and the packet data of the best effort type flow is transmitted in the order output from the second input / output control means. A transmission device having transmission means. 2. The flow management means allocates a communication bandwidth necessary for bandwidth guarantee to the bandwidth guaranteed type flow from the predetermined communication bandwidth, and allocates the remaining communication bandwidth to the best effort type flow. The transmitting device according to claim 1, wherein the transmitting device is assigned to a flow. 3. The transmission timing determining means obtains a first time which is a time until a transmission timing for transmitting packet data of the bandwidth guaranteed type flow next, and a second time from the second input / output control means. A second time, which is a transmission time required to transmit the packet data output to the second, is obtained. If the second time is shorter than the first time, the second input / output control means The transmission device according to claim 1, wherein the transmission device determines to transmit the packet data output to the transmission device. 4. The transmission timing determining means, when it is necessary to transmit packets of a plurality of flows at the same transmission timing, selects one flow from the plurality of flows based on a predetermined priority, The transmission device according to claim 1, wherein the transmission device determines to transmit the packet data of the selected flow at the transmission timing. 5. 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 band-guaranteed flows, the time information is 4. The transmission device according to claim 3, wherein the first time is obtained by subtracting a time when it is determined that the packet data belonging to the flow is to be transmitted next from the indicated time. 6. The transmission timing determining means uses a communication bandwidth allocated to the best effort type flow and a packet size of packet data to be output next from the second input / output control means. 4. The transmitting apparatus according to claim 3, wherein the second time is obtained. 7. The transmission timing determination means according to claim 3, wherein said transmission timing determination means includes a plurality of timers provided corresponding to each of said flows and defining a time when said packet data belonging to the corresponding flow is transmitted next. Transmission device. 8. The first input / output control means and the second input / output control means.
At least one of the input / output control means of the above (1) classifies the input packet data of the flow for each flow to which the packet data belongs, and outputs the classified packet data for each flow in the order of input. The transmitting device according to claim 1. 9. The transmitting apparatus according to claim 1, wherein said packet data length is variable. 10. A communication system comprising: a receiving device; and a transmitting device that transmits packet data of a plurality of flows including a band-guaranteed flow and a best-effort flow to the receiving device via a communication line. The transmission device includes a first input / output control unit that outputs the input packet data of the guaranteed bandwidth type flow in the input order, and a second input / output control unit that outputs the input packet data of the best effort type flow in the input order. Output control means, flow management means for allocating the predetermined communication bandwidth to the bandwidth-guaranteed flow and the best-effort flow, and taking into account the bandwidth guarantee of communication using the allocated communication bandwidth. A transmission for determining a transmission timing of the packet data of the bandwidth guaranteed flow and the best effort flow. Timing determination means, at the determined transmission timing, transmits the packet data of the bandwidth guaranteed flow in the order output from the first input / output control means, and transmits the packet data of the best effort flow A transmission unit for transmitting the signals in the order of output from the second input / output control unit. 11. The flow management means allocates a communication bandwidth required for bandwidth guarantee to the bandwidth-guaranteed flow from the predetermined communication bandwidth, and allocates the remaining communication bandwidth to the best-effort-type flow. Claim 10 to assign to flow
A communication system according to claim 1. 12. A transmission method for transmitting packet data of a plurality of flows including a band-guaranteed type flow and a best-effort type flow using a predetermined communication bandwidth, wherein the input band-guaranteed type flow is provided. The packet data of the best-effort type flow is output in the input order for each flow, and the predetermined communication bandwidth is allocated to the band-guaranteed type flow and the best-effort type flow. In consideration of the bandwidth guarantee of the communication using the allocated communication bandwidth, the transmission timing of the packet data of the bandwidth guaranteed flow and the best effort flow is determined. At the transmission timing, the packet data of the bandwidth guaranteed type flow is transmitted in the output order, and the best Method of transmitting packet data flow over preparative the order to be the output. 13. A communication bandwidth required for bandwidth guarantee is allocated to said guaranteed bandwidth flow from said predetermined communication bandwidth, and the remaining communication bandwidth is allocated to said best effort flow. Transmission method described in. 14. A first time which is a time until a transmission timing at which packet data of the bandwidth guaranteed type flow is transmitted next.
And a second time which is a transmission time required to transmit the packet data to be output next from the second input / output control means is obtained. The second time is the first time 13. The transmission method according to claim 12, wherein when the time is shorter, it is determined that the packet data to be output next from the second input / output control unit is transmitted. 15. When the packets of a plurality of flows need to be transmitted at the same transmission timing, one flow is selected from the plurality of flows based on a predetermined priority, and the packets of the selected flows are selected. The transmission method according to claim 12, wherein it is determined that the data is transmitted at the transmission timing. 16. Using a timer for generating time information used to determine the timing of transmitting the packet data, for each of the band-guaranteed flows, from the time indicated by the time information, to the flow The transmission method according to claim 14, wherein the first time is obtained by subtracting a time when it is determined that the packet data belonging to the packet data is to be transmitted next. 17. Using the communication bandwidth allocated to the best-effort flow and the packet size of the packet data to be output next from the second input / output control means, the second time is calculated. The transmission method according to claim 14, wherein the transmission is performed. 18. The transmission method according to claim 12, wherein said packet data length is variable.