JP3183368B2 - Burst communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burst communication apparatus, and more particularly, to a virtual path (VP) and a virtual channel (VC) for which a path has already been set in a transmission network using ATM technology. The present invention relates to a burst communication device which enables cell transmission in burst units at any time.

[0002]

2. Description of the Related Art In order to enable cell transmission in a burst unit at an arbitrary time, a first method is to allocate a peak rate of a band to the communication, and a second method is necessary. When changing to the required bandwidth ("A
Reservation Principle with Applications to the ATM
Traffic Control ", Computer Networks and ISDN Syst
ems 24, pp. 321-334, 1992).

[0003] A first method of assigning a peak rate is:
Since a fixed peak rate is assigned to the communication method, cell transmission in burst units can be performed at any time.

[0004] Further, the second method of changing to a necessary band when necessary is to negotiate a band necessary for communication of the burst with the network before transmitting the burst, and as a result, change the band (bandwidth). Capacity increase). Thereafter, transmission of a burst is started. After the end of the burst transmission, the bandwidth is restored (reduced bandwidth capacity). Therefore, network resources can be effectively used.

[0005]

However, in the above-mentioned first conventional method, transmission of cells using a burst can be arbitrarily performed. However, when a burst is not transmitted, other communication uses the band. Cannot be used. For this reason, it is necessary to allocate a band even when it is not necessary, and there is a problem that waste occurs and network resources cannot be effectively used.

The second conventional method has a problem in that it takes a long time to negotiate with a network, so that a delay occurs. As described above, the conventional method cannot satisfy requirements such as efficient use of network resources or communication delay.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been made in view of the above-mentioned problems, and provides a burst communication apparatus capable of providing an efficient and prompt communication service in burst communication of an ATM network. The purpose is to provide.

[0008]

FIG. 1 is a block diagram showing the first principle of the present invention.

According to the present invention, an ATM in which communication nodes are connected by a transmission line, and a logical line is accommodated in the transmission line.
In a burst communication device used in a communication network, when a cell arrives, a cell identification means 1 for identifying a head cell, a middle cell, and a last cell of a burst, which is a set of cells, At the time of arrival, the accommodation judging means 2 for judging whether or not the burst can be accommodated in the communication band 6 using the burst by referring to the control information 3. And a control unit 5 for transferring cells belonging to a burst registered in the registration unit 4 to a transmission path, and discarding cells belonging to an unregistered burst.

FIG. 2 is a block diagram showing the second principle of the present invention.

Further, the present invention provides a burst communication device used in an ATM communication network in which communication nodes are connected by a transmission line and a logical line is accommodated in the transmission line.
When a cell arrives, a cell identification means 1 for identifying a head cell using a burst, which is a set of cells, an intermediate cell, a last cell, and communication using no burst, and a communication band 6 using burst are logically defined. An accommodation determination unit 2 that determines whether or not accommodation of communication using burst is possible for a band for communication using burst with reference to the control information 3;
A registration unit 4 for registering a communication whose burst has been accepted by the accommodation determination unit 2, and a communication band 7 that does not use bursts for cells of communication identified as not using burst communication by the cell identification unit 1. To the registration means 4
And a control unit 5 for transferring cells belonging to the burst registered in the communication unit to the communication band 6 using the burst and discarding cells belonging to the burst whose accommodation has not been accepted by the registration unit 4.

When the bandwidth capacity 6 for communication using N times the maximum bandwidth of communication using bursts is prepared, the accommodation determination means 2 of the present invention controls the number of bursts currently accommodated. It is stored in information 3, and if the number of accommodated bursts does not exceed N, it is determined that accommodation is possible.

Further, the accommodation determining means 2 of the present invention holds the sum of the communication bands of the bursts in the control information 3 and, when a communication band P using bursts is prepared, assigns the first cell of each burst to the cell. The value of the described communication band Pi of the burst is read, and if P + Pi does not exceed the sum total of the control information 3, it is determined that it can be accommodated.

Further, in the accommodation determining means 2 of the present invention,
If the head cell of the burst is not accepted, the transmission side is notified when the transmission side requests transmission.

The cell identification means 1 of the present invention identifies the first cell, the middle cell, the last cell, and the communication cell without using the burst by using the two bits of the header or the payload of the cell. .

Further, the cell identification means 1 of the present invention identifies whether or not communication using a burst is made based on the path identifier of the arriving cell, and identifies the first cell, middle cell and last cell using the channel identifier. Do.

Further, the cell identification means 1 of the present invention comprises an OAM
The cell is identified as the first cell or the last cell of the burst, and by using one bit of the header or the payload of the cell, the middle cell and the cell of the communication that does not use the burst are identified.

[0018]

According to the present invention, when a transmitting terminal transmits cells in burst units, the transmitting terminal transmits cells indicating the first cell (BOB), the middle cell (MOB), and the last cell (EOB) of the burst. The communication nodes on the path of the virtual path (VP) manage the bandwidth in burst units, and transfer / discard of cells is controlled accordingly. When the first BOB of the burst is received, all cells belonging to the burst are transferred, but when the BOB is not received, the entire burst is discarded.

Also, when the EOB does not arrive, the BOB
It is possible to arrive. Eventually, only bursts transferred in all communication nodes through which the VP passes are transmitted to the receiving terminal.

Further, the probability that the burst is transmitted to the receiving terminal successfully can be adjusted by setting the free capacity to the number of VPs accommodated in each transmission path. Usually all V
Since the maximum available capacity is smaller than the sum of the peak rates of P, efficient operation of network resources is possible.

Further, since there is no need to negotiate a bandwidth change with the network in advance, there is no delay due to a waiting time from the burst transfer request to transmission.

As described above, according to the present invention, it is possible to efficiently and quickly realize communication for transmitting cells in burst units by managing the bandwidth in burst units.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows the configuration of the burst communication system of the present invention. In the figure, a transmitting terminal 100 and a receiving terminal 20
0 is a communication node located between the communication device 50 _1-5
0 _n is connected by a link 60 ₁ to 60 _n, cells transmitted from the transmitting terminal 100 is sent to the receiving terminal 200 via the virtual path 70. However, the link here refers to a transmission medium such as an optical fiber transmission line, and includes a wireless transmission line.

FIG. 4 shows an outline of a communication apparatus according to the present invention.

The communication device 21 shown in FIG.
1, a routing table 41, and a burst control unit 51. The burst control unit 51 includes a resource control unit 91, a resource management unit 71, a control information holding unit 81, and a control signal communication unit 61.

In the configuration shown in the figure, a virtual path identifier (VPI) assigned to a cell in the ATM network (however, the present invention is applicable to both VP and VC,
In this embodiment, a virtual path (VP) is defined by a VP) and a routing table 41 of a communication node (communication device) 21.

The switch unit 31 refers to the VPI of the cell transferred via the transmission line 11 and refers to the routing table 41.
The cell is transferred to the transmission line 11 'based on the data of (1).

Resource management unit 71 of burst control unit 51
Performs bandwidth management in burst units. The procedure of this band management will be described later. The resource control unit 91 controls cell transfer and discard according to an instruction from the resource management unit 71. The control signal communication unit 61 notifies the receiving terminal of the control result of the cell from the resource control unit 71. The control information holding unit 81 holds control information such as a counter value referred to by the resource management unit 71, a sum of used bands, a free band capacity, and a registered VPI.

FIG. 5 shows a procedure for performing bandwidth management by the resource management unit of the present invention. Here, the cell includes BOB indicating the start of the burst, MOB indicating the middle of the burst, and EO indicating the end of the burst.
Either B or CO indicating that communication does not control cell transmission in burst units is indicated in the header or payload of the cell.

The resource management unit 71 sends a B
When the OB cell arrives (steps 1 and 2), the VP is referred to by referring to the control information stored in the control information holding unit 81.
If I is unregistered (Step 3, No) and there is a free band (Step 4, Yes), the VP of the cell is
I is registered (step 5), and the current value of the free space in the control information of the control information holding unit 81 is updated (step 6).
The data is transferred to the transmission path 11 '(step 9).

If there is no free space in the band as a result of referring to the control information (step 4, No), the arriving cell is discarded by the resource management unit 71. At this time,
Since the VPI is not registered, the M
Since all OB and EOB cells will be discarded,
This is notified to the transmitting terminal via the control signal communication unit 61 (step 7).

When the cell of the MOB arrives (steps 1 and 2), if it is a registered VPI (step 8, Yes), it is transferred (step 9).
If it is a PI (Step 8, No), it is discarded (Step 13).

When the EOB cell is registered (steps 1 and 2), if it is a non-registered VPI (step 10, No), it is discarded (step 13), but if it is registered, the VPI is registered. (Step 1
1) Change the free space of the control information band (step 1).
2) Perform cell transfer (step 9).

When a CO cell arrives (step 1,
Step 2) Since there is no need to perform bandwidth management in burst units, the data is transferred as it is (step 9).

<< First Embodiment >> A first embodiment of the present invention will be described below. The configuration of the communication node in this embodiment is the same as that of FIG.

A plurality of transmission paths 11 are connected to the communication node 21. In the transmission path 11, a plurality of VPs 101
Is housed. The VP is identified by the VPI,
The routing table 41 determines the output transmission path and the VPI on the transmission path. The switch unit 31 outputs the cell according to the information in the routing table 41 to the output transmission line 1.
Transfer to 1 '. The burst control unit 51 is provided in the communication node for each transmission path, and manages an available band of the transmission path in charge. Of course, the burst control unit 51 may be disposed at one location of the communication node to centrally manage all transmission paths.

FIG. 6 shows the structure of the cell. FIG. 9A shows a case where the cell type is set in the header,
(B) shows the case where it is set to 2 bits of the payload. The cell includes BOB indicating the start of the burst, MOB indicating the middle of the burst, and EO indicating the end of the burst.
B and CO indicating that burst communication is not used
Are shown using two bits of the header or the payload.

For example, BOB is "00", MOB is "01", EOB is "10", and CO is "11".
A terminal performing burst communication stores BOB, MOB, E in a cell.
It is sent with an OB indication. A terminal that is not performing burst communication sends a cell with the indication of CO added to the cell.

Assume that the peak rate of the burst communication is P, and the available bandwidth prepared in advance for each transmission path is N · P
And Therefore, N communications can be accommodated. When the number of burst communications is M, M ≧ N can be satisfied, and network resources can be effectively used.

Hereinafter, for simplicity, the case where N = 1 will be described. Normally, M = 1, but another burst communication can be performed during a period when the burst communication is not performed. That is, it is possible to accommodate two or more communications. In this way, network resources are effectively used.

FIG. 7 shows a procedure of bandwidth management by the resource management unit according to the first embodiment of this invention.

The resource management section 71 executes the procedure shown in FIG. 7 to manage the bandwidth in burst units. In this embodiment, the control information holding unit 81 stores the registered VPI,
The count C is held.

When a BOB cell arrives from the transmission line 11 (steps 100 and 101) and the cell is a VPI not registered in the control information holding unit 81 (step 10).
2, No), C <N (count value is smaller than the predetermined number of communication lines), and if there is a margin in the band (Yes in Step 103), the VPI is registered (Step 104), and C = C + 1. Increments the count of the control information holding unit 81 (step 105). As a result, all the cells of the burst to which the cell belongs are output to the output transmission line 1 via the resource control unit 91 and the switch unit 31.
1 '(step 111).

In step 103, C ≧ N
(The count value is equal to or more than a predetermined number of communication lines) and the band has no margin (step 103, No), the BO
Since B is discarded (step 112), the fact is notified to the transmitting terminal via the control signal communication unit 61 (step 106). Since cells belonging to the burst in which the BOB has been discarded have no VPI registered, all subsequent cells of the burst to which the cell belongs are also discarded. Here, the management of the free bandwidth is managed by the resource management unit 71 by the counter C, and the counter C indicates the number of communications currently accommodated in the free bandwidth. If it is assumed that a maximum of N communications can be accommodated in the empty band at the same time, and C = N, even if a new BOB cell arrives, the burst is discarded.

When the BOB cell arrives, if there is no available band and the BOB is discarded (step 106,
Step 112) When the BOB cell is discarded, the transmission terminal 1 notifies the discard of the discard via the control signal communication unit 61.
Notify 1. This notification may be sent in a signaling cell or
This is performed by the OAM cell.

In step 101, when the arriving cell is the MOB, if the VPI of the BOB of the burst has been registered (step 107, Yes), the cell is transferred to the output transmission line 11 'via the switch unit 31. Will be transferred. If the VPI is not registered (step 107, N
o), discard the cell (step 112).

When the EOB cell arrives (steps 100 and 101) and its VPI is registered (step 108, Yes), since the end of the burst, the VPI registration is deleted and the counter C Decrease the value by one.

A registered VPI MOB cell or CO
If a cell arrives (steps 100, 101, 1
07, Yes), do nothing and transfer the cell. In this case, since the band used in the burst communication is fixed at P, the band can be managed by the counter C.
For communication using a CO cell (communication not using burst), a band is allocated in advance separately from an empty band used for burst communication.

The above processing is performed for each communication node, and finally a burst is transmitted to the receiving terminal. Therefore, unlike the conventional case where the capacity is changed, there is no processing / delay associated with the capacity change, so that the burst transfer can be performed at a high speed.

<< Second Embodiment >> Next, a second embodiment will be described. In the first embodiment, the peak rate of the burst communication is fixed to P and one type, but a process in the case where the peak rate of the band differs for each communication will be described.

In the case of the first embodiment described above, the management of the free band is realized by the counter of the control information holding unit 81. However, here, a memory is prepared in the control information holding unit 81 and is stored in the memory. The sum of the bands actually used is held, and the reception of the burst is determined by comparing with the free band.

Therefore, the control information holding unit 81 holds the used band, the free band, and the registered VPI. When the peak rate Pi of each communication is known to the communication node in advance, Pi is set in the control information holding unit 81, and Pi during communication is set.
(Psum) is managed. However, if the communication node does not know Pi, BOB and EOB are changed to O as shown in FIG.
It must be realized by an AM cell. An OAM cell is indicated by a particular VCI value. The type of the OAM cell is indicated by a field defined on the payload, and indicates that the OAM cell is an OAM cell according to the present invention. BOB and EOB are indicated using one bit on the payload. A field indicating the peak rate is provided in the payload.

FIG. 9 shows a procedure of bandwidth management by the resource management unit according to the second embodiment of the present invention.

When a BOB cell arrives (step 20)
0, Step 201, Step 202), Pi is read from the control information holding unit 61, and if the sum (Psum + Pi) of the communication band when the burst is accepted is equal to or less than the available bandwidth capacity (Yes in Step 203), the reception is accepted. Is registered (step 204). Otherwise, it is not accepted (step 206).

If the EOB arrives and is a registered VPI (step 200, step 201, step 20)
7, Yes), the registration is deleted (step 209), and Pi is deleted.
Is subtracted (step 210). In this case, MOB, C
O can be identified by one bit of the header or the payload.

According to the above procedure, even when the peak rate differs for each communication, the bandwidth can be managed in burst units.

Third Embodiment Next, a third embodiment will be described. In both the first and second embodiments, the burst management function is incorporated in the communication node. In this embodiment, an example in which the burst management function is implemented by another external device will be described.

FIG. 10 shows a system configuration according to the third embodiment of the present invention.

The communication node 600 shown in the figure has no function of managing bursts. VP that performs burst communication
Are routed to a specific transmission path. The burst management device 610 is connected to the communication node 600, and receives an output cell of the communication node 600 and an output cell of the burst management device 610.

The burst management device 610 calculates the V of the input cell.
The output transmission path of the communication node can be known from the PI. Therefore, it is possible to manage the free bandwidth for each output transmission line of the communication node.

The sequence performed by the burst management unit 611 of the burst management device 610 is the same as that of the first embodiment described above.
Any of the second embodiments may be used.

In the above-described embodiment, the description has been given of the method in which the BOB may arrive before the EOB arrives. However, if the BOB arrives before the EOB, it is regarded as abnormal and the VPI registration is performed. Can be erased and subsequent cells can be discarded. Also, the maximum burst length is set in advance,
The counting of the number of cells is started from the arrival of the BOB cell, and a burst exceeding the maximum value can perform a burst end sequence even if the EOB does not arrive. The burst end sequence may be voluntarily performed by each communication device, or the communication device located at the entrance of the network may transmit the EOB.
Cells may be sent. Also, set a time limit and set the BO
Even if the EOB does not arrive after a certain period of time from the arrival of B, the burst end sequence can be performed. In this case, the length of time can be made variable according to the peak rate.

It is also possible not to notify the transmitting terminal when the BOB is discarded.

Note that BOB, MOB, EOB, and CO are identified using the header or 2 bits of the payload as described in the above embodiment, but when the present invention is implemented based on VP, Since it is possible to discriminate between communication using a burst and communication not using the VPI, it is possible to assign a specific VCI value to each of BOB, MOB, and EOB to identify them.

[0066]

As described above, according to the present invention, the communication for transmitting a burst at an arbitrary time can be performed without adding a communication delay by adding a bandwidth management function for each burst to a communication node. Burst communication can be serviced efficiently and quickly.

[Brief description of the drawings]

FIG. 1 is a first principle configuration diagram of the present invention.

FIG. 2 is a second principle configuration diagram of the present invention.

FIG. 3 is a configuration diagram of a burst communication system according to the present invention.

FIG. 4 is a diagram showing an outline of a communication device of the present invention.

FIG. 5 is a diagram illustrating a procedure in which a resource management unit of the present invention performs band management.

FIG. 6 is a diagram showing a configuration of a cell.

FIG. 7 is a diagram illustrating a procedure of band management of a resource management unit according to the first embodiment of this invention.

FIG. 8 is a diagram showing a configuration of each cell according to a second example of the present invention.

FIG. 9 is a diagram illustrating a procedure of bandwidth management of a resource management unit according to a second embodiment of this invention.

FIG. 10 is a system configuration diagram of a third embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 cell identification means 2 accommodation determination means 3 control information 4 registration means 5 control means 6 communication band using burst 7 communication band not using burst 11, 11 'transmission path 21 communication device 31 switch unit 41 routing table 50 link 51 Burst control unit 60 Communication device 61 Control signal communication unit 70 Virtual path 71 Resource management unit 81 Control information holding unit 91 Resource control unit 100 Transmission terminal 101 Virtual path 200 Receiving terminal 600 Communication node 610 Burst management device 611 Burst management unit

Continuation of front page (72) Inventor Noji Kanayama 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-7-66807 (JP, A) JP-A-3-3 135248 (JP, A) JP-A-4-345241 (JP, A) Proceedings of the 1994 IEICE Spring Conference B-765 (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12 / 28 H04L 12/56

Claims (2)

(57) [Claims] The communication nodes are connected by a transmission path,
ATM communication network in which a logical line is accommodated in a transmission line
In the burst communication device used in When all cells arrive, use the burst that is the set of the cells.
The first cell, middle cell, last cell and
The header or payload of the relevant cell
Cell identification means for identifying using two bits of the code, To a communication band using the burst prepared logically
On the other hand, whether communication using the burst can be accommodated.
Accommodation determination means for determining with reference to the control information; The communication in which the accommodation of the burst is accepted by the accommodation judgment means.
Registration means for registering Burst-free communication is identified by the cell identification means.
The communication cell to a communication band that does not use bursts.
To the bursts registered by the registration means.
Transfer to a band for communication using the burst, and
Belongs to a burst whose containment has not been accepted by the means
And control means for discarding cells.
Burst communication device. 2. The communication node is connected by a transmission path,
ATM communication network in which a logical line is accommodated in a transmission line
In the burst communication device used in Start of burst by OAM cell when all cells arrive
Cell or the last cell, and
By using one bit of the header or payload,
It must be a cell that does not use a cell in the middle or a burst.
Cell identification means for identifying To a communication band using the burst prepared logically
On the other hand, whether communication using the burst can be accommodated.
Accommodation determination means for determining with reference to the control information; The communication in which the accommodation of the burst is accepted by the accommodation judgment means.
Registration means for registering Burst-free communication is identified by the cell identification means.
The communication cell to a communication band that does not use bursts.
To the bursts registered by the registration means.
Transfer to a band for communication using the burst, and
Belongs to a burst whose containment has not been accepted by the means
And control means for discarding cells.
Burst communication device.