JP3159961B2 - Cell receiving device and traffic control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell receiving apparatus and a traffic control system, for example, an ABR (Av
ATM that guarantees service class of “ailable bit rate”
It is suitable for application to an exchange of a network system.

[0002]

2. Description of the Related Art An ATM network system uses an ATM (Asynchronous Transfer) transmission system for transmitting data in units of cells by using data (called cells) divided into fixed lengths as the minimum unit of data flowing in the network.
Mode).

Since the cell structure is small and has a fixed length, high-speed processing by hardware is possible. A feature is that even data having different characteristics, such as voice, image, and data for computer processing, can be stored in a cell and a service can be provided as needed through an ATM network system.

[0004] In order to cope with various services required for data to be handled, service categories are defined in the ATM, and a user selects an optimum service category in accordance with characteristics of data to be put on a network. .

[0005] One of the service categories is an ABR service. The ABR specifies a minimum bandwidth and a maximum bandwidth, and the network strives to provide as much traffic and transmission quality as possible to the serviced connection between the bandwidths. In the ABR service, a cell in which resource management information called an RM (Resource Management) cell is exchanged between connections, and resource management is performed so that the connection does not fail.

[0006] In the ABR service, there are several means used by an ATM switch to perform traffic control. One of the main methods is R.
There is an ER marking method for managing a band by ER (Explicit Rate) information recorded in an M cell.

FIG. 2 is a diagram for explaining the ER marking method. In FIG. 2, an RM cell in which the transmission rate of the resource node is written is output for each connection at a predetermined timing from the resource node 210 of the ABR service, and the ATM switch 220 outputs the RM cell based on the processing capability of the switch. Explicit rate information (ER information) indicating how much the rate can be reduced or increased from the transmission rate written in the RM cell
Is written to the RM cell and sent back to the source resource node 210. In the resource node 210, the next transmission rate is controlled based on the ER information written in the returned RM cell.

[0008] As described above, the ER indicates the band that the connection can provide for the data source, is recorded in the RM (Resource Management) cell, and is determined by each switch in the network through which the connection passes. It will be rewritten to a band that can be provided.

[0009]

By the way, in the ER marking system, which is one of the ABR traffic control systems, as described above, the processing capability of the switch through which the connection passes the ER value (the real-time used bandwidth and congestion of congestion). Must be calculated according to the degree, etc.
The algorithm for the R calculation is not defined in the recommendation, and various calculation methods have been conventionally proposed.

However, in the various calculation methods proposed in the prior art, since the ER is an estimate of the processing capacity of the ATM switch through which the connection passes, the queue of the shaper (which functions to keep the output rate constant) in the switch is provided. Is determined in consideration of the congestion information and the current input rate of the cell, or some factors in addition thereto, the calculation is complicated, and therefore, the hardware configuration of the ER calculation is complicated, and the processing speed is slow. There was a problem of becoming.

In a normal ER marking system, A
The bandwidth that can be distributed to the entire BR service connection is fairly distributed to each connection (fair share). For more precise bandwidth management, the ABR connection is divided into any number of groups, and the groups are divided into groups. An intra-group fair share scheme that fair shares bandwidth within the group has also been proposed. In this intra-group fair share method, there is no generally known ER calculation method.

Here, the intra-group fair share scheme is
When trying to realize each group by the conventional ER marking method, in order to manage the ER in units of divided groups, the switch has as many shaping queues as the number of divided groups in the switch and receives the congestion information thereof. There is a problem that the hardware configuration becomes more complicated and the processing speed becomes slower than the normal ER marking method, such as performing ER calculation for each group.

Therefore, there has been a demand for a cell receiving device and a traffic control system having a simple hardware configuration and a high processing speed.

[0014]

According to a first aspect of the present invention, there is provided a resource management system having transmission band information of each connection inserted between information cells via one or a plurality of switch means. (1) The latest transmission band of each connection is stored in the cell receiving side device, and when the resource management cell arrives, the resource management unit receives the resource based on the transmission band information of the incoming resource management cell. Transmission bandwidth storage means for updating the latest transmission bandwidth of the connection of the management cell; and (2) when the resource management cell arrives,
The bandwidth that can be transmitted by the incoming resource management cell connection is calculated from the latest transmission bandwidth of each connection stored in the transmission bandwidth storage means and the maximum transmission bandwidth allocated to the entire connection. Resource management cell returning means for returning the resource management cell having the available bandwidth information.

A second aspect of the present invention is a resource management system which inserts a resource management cell having transmission band information of a connection for each connection on a transmission side of an information cell transmitted via one or a plurality of switch means. In the traffic control system including the management cell insertion means, (1) storing the latest transmission band of each connection on the receiving side of the information cell transmitted via the switch means, and arriving when the resource management cell arrives; Transmission band storage means for updating the latest transmission band of the connection of the resource management cell, based on the transmission band information of the resource management cell, (2)
When a resource management cell arrives at the receiving side of the information cell transmitted via the switch means, the bandwidth that can be transmitted by the incoming resource management cell connection is stored in the transmission bandwidth storage means. Resource management cell returning means for calculating a resource management cell having the calculated available transmission bandwidth information from the latest transmission bandwidth and the maximum transmission bandwidth allocated to the entire connection, and (3)
On the transmitting side of the information cell to be transmitted via the switch means, the next transmission band of each connection is determined based on at least the transmittable bandwidth information of the resource management cell returned from the resource management cell returning means. And transmission band control means for transmitting information cells to the switch means in the determined transmission band.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (A) First Embodiment Hereinafter, a cell receiving apparatus and a traffic control system according to the present invention will be described by using an ATM which guarantees an ABR service class.
A first embodiment applied to an exchange of a network system will be described in detail with reference to the drawings.

(A-1) Description of the Configuration FIG. 1 is a block diagram showing the configuration of the ATM switch of this embodiment. In FIG. 1, this ATM switch is A
BR control unit 110 and VCS (Virtual ChannelShaper)
It has an incoming line IF having a unit 120, an ATM switch unit 130, and an outgoing line IF having a VPS (Virtual Path Shaper) unit 140 and an ABR control unit 150.

The ABR control unit 110 includes an input cell rate calculation unit 111 and a CCR (Current Cell Rate) setting unit 1
12 and an ACR (Allowed Cell Rate) calculation unit 113, and each of these components has a function described below.

The input rate calculator 111 calculates the input rate of each connection of the ABR based on the number of cells arriving for each connection.

The ACR calculation unit 113 includes an ABR control unit 15
Based on the ER information written in the RM cell returned from 0, the information on the minimum bandwidth and the maximum bandwidth previously declared at the time of setting each connection of ABR, the information that the user wants to increase the predetermined ABR connection bandwidth, etc. It calculates the ACR (permissible cell rate) of the connection.

The CCR setting section 112 calculates the VCS section 12 based on the input rate of each connection of ABR calculated by the input rate calculation section 111 and the allowable cell rate of each connection of ABR calculated by the ACR calculation section 113.
CCR (outflow cell rate) of each connection flowing from 0
Is set.

The VCS unit 120 prepares a queue for each ABR connection, shapes the connection for each connection based on the CCR set by the CCR setting unit 112, and provides the ATM switch unit 130 with the shaped data. Also, V
The CS unit 120 writes the set CCR information into the R
An M cell is generated for each connection, the address of the connection is added, and the cell is inserted between transmission cells.

The ATM switch 130 exchanges incoming cells for each connection based on the address information attached to the header section of the incoming cells.

The VPS unit 140 has a queue prepared for each service class, and shapes cells exchanged by the ATM switch unit 130 for each service class. Here, the VPS unit 140 is provided with a queue for an ABR connection, and all cells of the connection receiving the ABR service are stored in this queue and output at a constant rate.

The ABR control unit 150 includes an ER calculation unit 151
The ER calculation unit 151 has the following functions.

When the RM cell inserted by the VCS unit 120 is given from the VPS unit 140, the ER calculation unit 151
CCR of the connection of this RM cell from this RM cell
Based on the read CCR information, the latest CCR information read from the RM cell of another ABR connection given so far, and the bandwidth allocated to the ABR connection by the VPS unit 140, ER indicating the rate that can be currently transmitted in the connection of the RM cell is calculated (a specific calculation method will be described later),
The calculated ER information is written in the RM cell, and is sent back to the ABR control unit 110 that is the transmission source.

(A-2) Description of Operation The operation of the ATM exchange having the above configuration will be described with reference to FIGS.

The ABR control unit 110 calculates the input rate of each connection of the ABR based on the number of arriving cells, and writes the ER written in the returned RM cell.
ACR (allowable cell rate) of each connection of the ABR is calculated based on the information and other various information described above,
Based on the calculated input rate and allowable cell rate, the CCR of each connection of the VCS unit 120 is set.

In the VCS unit 120, a queue is prepared for each ABR connection, and an incoming ABR cell
The ATM switch 130 is shaped for each connection based on the CCR set by the BR controller 110 and
Given to. Further, an RM cell in which the set CCR information is written is generated for each connection, and inserted between transmission cells. The ATM switch unit 130 performs switching connection for each connection based on the address information attached to the header part of the incoming cell. The VPS unit 140 prepares a queue for each service class.
The cells exchanged in 30 are shaped for each service class. Here, the VPS unit 140 is provided with a queue for an ABR connection, and all cells of the connection receiving the ABR service are stored in this queue and output at a constant rate.

Here, when the RM cell inserted by the VCS unit 120 is given from the VPS unit 140, the ABR control unit 150 (ER calculation unit 151) reads the CCR information of the connection of the RM cell from the RM cell. Issued
Based on this CCR information, the latest CCR information read from the RM cell of another ABR connection given so far, and the band allocated to the ABR connection by the VPS unit 140, the connection of this incoming RM cell The ER indicating the rate at which the current can be transmitted is calculated, the calculated ER information is written in this RM cell, and sent back to the ABR control unit 110 that is the transmission source.

FIG. 3 is a flowchart showing an ER calculation process in the ER calculation section 151. In FIG. 3, when an RM cell of a certain connection is given from the VPS unit 140 (step 301), the CCR information written in this RM cell is read (step 302), and the read CCR is stored in the VPS unit 140. From the band assigned to the ABR connection in the entire band of the ABR connection currently flowing from the VCS unit 120 (the latest CC of all the other ABR connections given so far)
ER is calculated by adding a value obtained by subtracting (R sum) (step 303). Here, if the calculated ER is lower than the minimum bandwidth guaranteed in advance when setting this connection (step 304), this ER is rewritten to the minimum bandwidth value (step 305). The ER information calculated in this manner is written into the incoming RM cell, and the RM cell is sent back to the ABR control unit 110 that is the transmission source (step 306).

In the ABR control unit 110, the next CCR of this connection is set based on the ER information of the returned RM cell.

(A-3) Description of Effects As described above, according to the present embodiment, each connection at the present time is determined based on the CCR of each connection of the ABR and the band allocated to the ABR connection by the VPS unit 140. ER that calculates the ER indicating the band that can flow
Since the calculation unit 151 is provided, the VPS
The ER calculation is simplified, the ER calculation is simplified, the hardware configuration of the ER calculation unit 51 is simplified, and the calculation speed can be improved without requiring the congestion information of the unit 140 and other information.

(B) Second Embodiment Hereinafter, a cell receiving apparatus and a traffic control system according to the present invention will be described by using an ATM which guarantees an ABR service class.
A second embodiment applied to an exchange of a network system will be described in detail with reference to the drawings.

(B-1) Description of Configuration FIG. 4 is a block diagram showing the configuration of the ATM exchange according to this embodiment. In FIG. 4, the ATM exchange is
It has an incoming line IF having a BR control unit 410 and a VCS unit 420, an ATM switch unit 430, and an outgoing line IF having a VPS unit 440 and an ABR control unit 450.

Here, the ABR control unit 410 and the VCS unit 4
20, the ATM switch unit 430, and the VPS unit 440 are the same as the components having the same names described in the first embodiment, and a description thereof will be omitted. Therefore, the ABR control unit 450 will be described below.

The ABR control unit 450 includes an ER calculation unit 451
This ER calculation unit 451 has a VPS
When the RM cell inserted by the VCS unit 420 is given from the unit 440, the RM cell
R information is read, and the read CCR information and another ABR in the same group as the connection of the given RM cell.
Based on the latest CCR information read from the RM cell of the connection and the bandwidth allocated to the given group of RM cell connections by VPS section 440, the rate that can be currently passed through this incoming RM cell connection Is calculated (a specific calculation method will be described later), and the calculated ER information is written in this RM cell and sent back to the ABR control unit 410 that is the transmission source.

(B-2) Description of Operation The operation of the ATM exchange having such a configuration will be described with reference to FIG. 5 focusing on points different from the first embodiment, that is, the calculation processing of the ER calculation unit 451. It will be described with reference to FIG.

FIG. 5 is a flowchart showing an ER calculation process in the ER calculation unit 451. In FIG. 5, when an RM cell of a certain connection is provided from the VPS unit 440 (step 501), the CCR information written in this RM cell is read (step 502), and this connection is stored in the read CCR. From the bandwidth assigned to the group having the ABR connection of the current group flowing through the VCS unit 420 (the latest bandwidth of the other ABR connection of this group)
ER is calculated by adding the value obtained by subtracting (the sum of CR information) (step 503). Here, if the calculated ER is a value lower than the minimum bandwidth previously guaranteed at the time of setting this connection (step 504), the ER is rewritten to the minimum bandwidth value (step 505). The ER information calculated in this way is written to the incoming RM cell,
The RM cell is sent back to the source ABR control unit 410 (step 506).

(B-3) Description of Effects As described above, according to this embodiment, the same effects as those of the first embodiment can be obtained, and the ER calculation unit 451 calculates the CCR of each connection of the ABR. VPS unit 44
0, the bandwidth allocated to the ABR connection is managed and set for each of the divided ABR groups.
The PS unit 440 has one physical queue for the ABR connection. However, the same effect as when a queue is logically provided for each group can be obtained, and the configuration is the same as that of the first embodiment. The ER can be managed for each group.

(C) Other Embodiments In each of the above embodiments, the present invention is applied to an exchange of an ATM network system which guarantees an ABR service class. Of course, the present invention can be applied to a system.

In each of the above embodiments, a case has been described in which service classes other than ABR are also mixed.
The cell of the service class of only ABR may be exchanged.

In each of the above embodiments, the traffic control is performed for the ABR service class. However, a service class similar to the ABR will be defined in the future. Of course, it can be applied to classes. That is, it is not limited to the ABR service class.

Further, in each of the above embodiments, the ATM
Although the exchange has one incoming line IF and one outgoing line IF, the same applies to a case where one or both of them are plural (in this case, the number is actually larger). The present invention can be applied.

[0045]

As described above, according to the first and second aspects of the present invention, (1) storing the latest transmission band of each connection, and when the resource management cell arrives, the incoming resource management cell Transmission bandwidth storage means for updating the latest transmission bandwidth of the resource management cell connection based on the transmission bandwidth information contained in (2), and (2) when the resource management cell arrives, the connection of the resource management cell arrives. A resource management cell having a transmittable band calculated from the latest transmission band of each connection stored in the transmission band storage means and the maximum transmission band allocated to the entire connection, and having the calculated transmission band information. And a resource management cell return means for returning the transmission bandwidth, so that the calculation element of the transmittable bandwidth is the latest transmission bandwidth of each connection and the maximum transmission allocated to the entire connection. In band alone, without requiring other elements, it simplifies the calculation of the allowable communication bandwidth, therefore, the hardware configuration can be simplified, and the processing speed is increased.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an ATM exchange according to a first embodiment.

FIG. 2 is a diagram illustrating the operation of a conventional ER marking method.

FIG. 3 shows E in the ER calculator 151 of the first embodiment.
It is a flowchart which shows R calculation processing.

FIG. 4 is a block diagram illustrating a configuration of an ATM exchange according to a second embodiment.

FIG. 5 shows E in the ER calculation unit 451 of the second embodiment.
It is a flowchart which shows R calculation processing.

[Explanation of symbols]

 140 ... VPS section, 151 ... ER calculation section.

Continuation of the front page (56) References JP-A-9-107364 (JP, A) JP-A-10-70536 (JP, A) JP-A-10-107801 (JP, A) JP-A-11-163879 (JP, A) JP-A-2000-13378 (JP, A) JP-A-2000-151652 (JP, A) JP-A-2000-92078 (JP, A) JP-A-8-149134 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 12/56 H04L 12/28

Claims (8)

(57) [Claims] An apparatus for receiving a resource management cell having transmission band information of each connection inserted between information cells via one or a plurality of switch means, comprising: Transmission bandwidth storage means for updating the latest transmission bandwidth of the connection of the resource management cell based on the transmission bandwidth information of the incoming resource management cell when the resource management cell arrives; When the service cell arrives, the bandwidth that can be transmitted by the connection of the incoming resource management cell is determined from the latest transmission bandwidth of each connection stored in the transmission bandwidth storage means and the maximum transmission bandwidth allocated to the entire connection. And a resource management cell returning means for returning a resource management cell having the calculated available transmission bandwidth information. Le receiving device. 2. The resource management cell return means divides each connection into a plurality of arbitrary groups, and allocates a band that can be transmitted by an incoming resource management cell connection to a maximum transmission allocated to the connection group. 2. The cell receiving apparatus according to claim 1, wherein the calculation is performed from a band and a latest transmission band of each connection of the group stored in the transmission band storage means. 3. The transmission band storage means stores the latest transmission band for each connection of a predetermined service class, and the resource management cell returning means stores the latest transmission band for each connection of the predetermined service class. 3. The cell receiving apparatus according to claim 1, wherein a bandwidth that can be transmitted by the connection of the arriving resource management cell is calculated and the resource management cell is returned. 4. The cell receiving apparatus according to claim 3, wherein the predetermined service class is an ABR service class. 5. A resource management cell insertion unit for inserting a resource management cell having transmission band information of a connection for each connection on a transmission side of an information cell transmitted via one or a plurality of switch units. In the traffic control system, the latest transmission bandwidth of each connection is stored on the receiving side of the information cell transmitted via the switch means, and when the resource management cell arrives, the transmission bandwidth information contained in the incoming resource management cell is stored. Based on the transmission band storage means for updating the latest transmission band of the connection of the resource management cell, and the resource management cell arrives at the receiving side of the information cell transmitted via the switch means. The band that can be transmitted by the connection of the resource management cell is the latest transmission band of each connection stored in the transmission band storage means. Resource management cell returning means for calculating a resource management cell having the calculated transmission bandwidth information calculated from the maximum transmission bandwidth allocated to the entire connection, and transmitting the information cell transmitted via the switch means. On the side, a next transmission band of each connection is determined based on at least the transmittable bandwidth information of the resource management cell returned from the resource management cell returning means, and the information cell is switched in the determined transmission band by the switching means. And a transmission band control unit for transmitting the traffic to the traffic control system. 6. The resource management cell returning means divides each connection into an arbitrary plurality of groups, and allocates a band that can be transmitted by an incoming resource management cell connection to a maximum transmission allocated to the connection group. 6. The traffic control system according to claim 5, wherein the calculation is performed from a band and the latest transmission band of each connection of the group stored in the transmission band storage means. 7. The resource management cell insertion unit inserts a resource management cell for each connection of a predetermined service class, and the transmission band storage unit inserts a resource management cell for each connection of the predetermined service class. The latest transmission band is stored, and the resource management cell return means calculates, for each connection of the predetermined service class, a band that can be transmitted by the connection of the incoming resource management cell, and calculates the resource management cell. The transmission band control means determines a next transmission band for each connection of the predetermined service class, and transmits information cells in the determined transmission band. 3. The traffic control system according to 1. 8. The traffic control system according to claim 7, wherein the predetermined service class is an ABR service class.