JP2865049B2 - ATM network communication 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 communication system having a communication band changing function in an ATM network, and more particularly to a communication system suitable for processing a band increase request.

[0002]

2. Description of the Related Art Conventionally, an ATM network communication system having this kind of communication band changing function is disclosed in a literature ("Fast Bandwidth Allocation in ATM Networks"("Fast Bandwidth Allocat").
ion in ATM networks ")", October 1992, IS'92, Issue 2, .A5.2 (ISS '92, vol.2, .A5.2, O
ct. 1992), it is used to change the bandwidth used by a certain communication channel.

FIG. 5 is a block diagram showing an example of a conventional ATM network communication system having a communication band changing function.

Referring to FIG. 5, a node 29 is a packet transmitting node composed of a connection control unit 32 and a data transmitting unit 33, and establishes and disconnects a connection serving as a communication channel, changes a connection band, and performs cell switching. It has a function of sending the packetized packet to the receiving node. The connection control unit 32 includes a connection opening unit 21 and a one-to-one connection table 22. The data transmission unit 33 includes a delivery connection determination unit 23 and a cell unit 24.

[0005] The node 30 is a packet receiving node composed of a connection control unit 34 and a data receiving unit 35. The node 30 restores cells delivered from the transmitting node into packets, requests connection establishment and bandwidth change. Has the function of returning permission to the transmitting node. The connection control unit 34 is connected to the connection opening units 25 and 1
And a one-to-one connection table 26. The data receiving unit 35 includes the packetizing unit 28 and the packet buffer 27.

The connection 31 is a connection for connecting the node 29 and the node 30, and is a connection via a plurality of ATM switches on the ATM network 36.

The connection opening unit 21 of the node 29 and the connection opening unit 25 of the node 30 open the connection 31 used for communication on the ATM network 36, and store the opened connection in the one-to-one connection table 22 and the one-to-one connection table. Type 1 connection table 26
Has the function of writing to

FIG. 7 shows the contents of the one-to-one connection table 22 of the node 29 and the one-to-one connection table 26 of the node 30. As shown in FIG. 7, the one-to-one connection table 22 of the node 29 and the one-to-one connection table 26 of the node 30 are tables showing the correspondence between the session ID to which the packet belongs, the connection ID, and the bandwidth. , Session I
D and connection ID are associated one-to-one.

The delivery connection determining unit 23 of the node 29
Has a function of referring to the connection table 22 to determine a connection for delivering a packet. Node 2
9 has a function of decomposing a packet delivered to the connection 31 into cells.

The packetizing section 28 of the node 30 has an ATM
It has a function of restoring cells delivered from the network 30 into packets. The packet buffer 29 of the node 30 has a function of storing the packet sent by the packetizing unit 28.

Next, the operation of the conventional ATM network communication system having a communication band changing function shown in FIG. 5 will be described. FIG. 6 is a flowchart for explaining an operation when a bandwidth change request is made in the conventional ATM network communication system shown in FIG.

When the node 29 receives a bandwidth change request for an existing connection (step 301), the bandwidth change request is passed to the connection opening unit 21, and the establishment of a connection having a bandwidth satisfying the request is sent to the ATM network 36. Request (step 302).

If the connection that satisfies the requested bandwidth is successfully established in step 302, the flow branches to "Yes" in step 302, and the connection table 22 is updated based on the change (step 3).
04), the process ends. At this time, also in the node 30, the connection opening unit 25 sends the ATM network 3
6, the connection table 26 is updated.

On the other hand, in step 302, if the establishment of a connection that satisfies the requested bandwidth fails, the process branches to "No" in step 302, and returns a notification of the failure of the bandwidth change to the request source (step 302). Step 303), the process ends.

As described above, when a connection that satisfies the requested bandwidth is established and the delivery of the data packet is started, the data packet delivered from the node 29 is passed to the delivery connection determining unit 23, A connection ID to be delivered is determined in accordance with the session ID to which this belongs. The data packet is converted into the cell unit 24.
, And is decomposed into cells and transmitted over the ATM network 36. The transmitted cell is delivered to the node 30 by the determined connection (connection 31) of the ATM network 36, and is reconstructed from the cell to the packet by the packetizing unit 28 of the node 30. The reconstructed packet is stored in the packet buffer 27.

[0016]

However, in the conventional ATM network communication system having the communication band changing function as described above, the band of the connection currently used in response to the band change request is set on the same path. The upper limit of the bandwidth of the connection is determined by the bandwidth between the ATM switches on the ATM network, and the bandwidth that is equal to or greater than the maximum bandwidth of the connection path currently used is adopted. There is a problem that it is not possible to set the connection that has.

Therefore, the present invention has been made in view of the above-mentioned problems, and the connection bandwidth is distributed and utilized on the ATM network irrespective of the connection path currently used. An object of the present invention is to provide an ATM network communication system capable of making a change.

[0018]

To achieve the above object, the present invention relates to an ATM network communication system having a function of changing the bandwidth of an ATM network connection comprising a plurality of ATM switches and a plurality of ATM nodes. When a bandwidth change request for an existing connection on the ATM network fails on a predetermined single path, a connection with an increased bandwidth is opened on another path, and the existing connection and the An ATM network communication system characterized by improving the success rate of setting a connection having a requested bandwidth by diverting a packet to a connection having an increased bandwidth.

In the ATM network communication system according to the present invention, it is preferable that the packet is divided according to a bandwidth ratio between the existing connection and a connection having the increased bandwidth.

Further, in the ATM network communication system according to the present invention, it is preferable that the packets are divided according to the amount of untransmitted packets in a transmission buffer managed for each connection.

Further, in the ATM network communication system according to the present invention, it is preferable that the process of integrating a plurality of connections into which the packet is diverted is executed at predetermined intervals to suppress an increase in the number of connections.

Next, the principle or operation of the present invention will be described. In the ATM network communication system according to the present invention, when it is impossible to increase the bandwidth on a predetermined single path, a connection having the increased bandwidth is opened on another path and the packet is distributed to a plurality of connections. By doing so, it is possible to cope with a band change exceeding the upper limit of the band on a single path.

FIG. 2 is a diagram for conceptually explaining the principle or operation of the ATM network communication system according to the present invention. The principle or operation of the present invention will be described in more detail with reference to FIG. 2. A connection is established on a path 55 passing through an ATM switch 53 between a node 51 and a node 52 connected via an ATM network 57. It is assumed that an attempt is made to change the bandwidth of this connection to a value exceeding the upper limit of the route 55. In this case, although the band change fails in the above-described conventional ATM network communication system, in the ATM network communication system of the present invention, it is determined whether or not the band of the path 56 passing through the ATM switch 54 is vacant by the increase of the change request. If the connection is free, a new connection is opened on the route 56, and a packet is diverted to the existing connection and the connection having the increased bandwidth, thereby realizing a change in the bandwidth of the connection. It is possible to do.

As described above, according to the ATM network communication system of the present invention, the effective use of the vacant bands distributed on the ATM network is realized, and the upper limit of the band on the single path of the ATM network is affected. Instead, the band can be changed.

Further, according to the ATM network communication system of the present invention, the division of packets, that is, the distribution of packets to a plurality of connections, is performed according to the bandwidth ratio of the connections or the untransmitted packets held in the transmission buffer table. By performing the processing according to the amount, it is possible to efficiently distribute packets to a plurality of connections.

Further, according to the ATM network communication system of the present invention, the integration process for integrating a plurality of divided connections is executed at predetermined intervals, thereby integrating the connections that can be integrated into one and reducing the number of connections. It is possible to suppress the increase and reduce the load of connection management in the ATM network.

[0027]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the ATM network communication system of the present invention.

Referring to FIG. 1, a node 12 is a packet transmitting node composed of a connection control unit 16 and a data transmitting unit 17, and establishes and disconnects a connection serving as a communication channel, changes a connection band, and changes a cell. It has a function of sending the packetized packet to the receiving node. The connection control unit 16 includes a connection opening unit 1, a connection opening control unit 2, a 1: N connection table 3, a connection integration unit 4, and a timer 5.
It is composed of The data transmission unit 17 includes a delivery connection determination unit 6 with a packet distribution function and a cell unit 7.

The node 13 is a packet receiving node composed of a connection control unit 18 and a data receiving unit 19. The node 13 restores a cell delivered from the transmitting node to a packet, and issues a connection opening request and a bandwidth change request. Has the function of returning permission to the transmitting node. The connection control unit 18 includes a connection opening unit 8 and a 1: N connection table 9. The data receiving unit 19 includes the packetizing unit 11 and the packet buffer 1
0.

Connection 14 and Connection 15
Is a connection connecting between the node 12 and the node 13, and a plurality of ATMs on the ATM network 20.
This is a connection via a switch.

The connection opening section 1 of the node 12 has a function of opening and closing a connection and changing a connection bandwidth. Connection establishment control unit 2
Has a function of passing a connection opening request to the connection opening unit 1, issuing a connection opening request for increasing connection depending on the success or failure of the bandwidth change request, and writing the result to the one-to-N type connection table 3.

FIG. 4 shows the contents of the one-to-N connection table 3 of the node 12. As shown in FIG.
The type connection table 3 is a table showing a correspondence relationship between a session ID to which a packet belongs, a connection ID, and a bandwidth, and can take a plurality of connection ID and bandwidth entries for one session ID. The one-to-N connection table 3 is updated when a connection is newly opened or a bandwidth is changed, and is referred to when deciding which connection to deliver a packet to and when managing the connection. You.

The connection integration unit 4 of the node 12 uses the periodic signal from the timer 5 as a trigger to determine whether a session formed from a plurality of connections can be integrated into one connection. To the connection establishment unit 1. The timer 5 of the node 12 has a function of periodically sending a signal to the connection integration unit 4.

The delivery connection determining unit 6 with the packet distribution function of the node 12 determines the session ID to which the packet belongs.
The connection to which the packet is to be delivered is determined with reference to the one-to-N connection table 3 based on
When a plurality of connections are assigned to one session ID, a function of distributing packets to each connection according to the bandwidth ratio of the plurality of connections is provided.

The distribution of packets to a plurality of connections is performed not only according to the bandwidth ratio of the connections but also according to the amount of untransmitted packets in the transmission buffer held in the transmission buffer table. You can also. Specifically, packets are preferentially distributed to connections with a small amount of untransmitted packets stored in a transmission buffer managed for each connection.

The celling unit 7 of the node 12 has a function of decomposing a packet delivered to the connection 14 and the connection 15 into cells and adding an identifier (connection ID) of the delivered connection to a header of the cell.

The connection opening unit 8 of the node 13 responds to the connection opening request from the node 12 and stores the opened connection in the one-to-N connection table 9.
Has the function of writing to

The one-to-N connection table 9 of the node 13 corresponds to the one-to-N connection table 3 shown in FIG.
Similarly, the connection ID corresponding to the session ID
9 is a table showing a correspondence relationship between a session ID and a bandwidth, and an entry for allocating one session ID to a plurality of connection IDs and bandwidths can be taken.

The packetizing unit 11 of the node 13 performs the
It has a function of reconfiguring cells delivered from the network 20 into packets. The packet buffer 10 has a function of storing packets sent from the packetizing unit 11.

Next, the operation of the embodiment of the ATM network communication system of the present invention shown in FIG. 1 will be described.

FIG. 3A is a flowchart for explaining the operation when a bandwidth change request is made in the ATM network communication system shown in FIG. In the following description, a case where another connection is opened in addition to the current connection is taken as an example. However, the same can be applied even when two or more connections are newly opened.

When the node 12 receives a bandwidth change request for an existing connection (step 101), the bandwidth change request is passed to the connection opening control unit 2 to satisfy the bandwidth requested for the connection opening unit 1. A request is made to open a connection (step 102).

If the connection establishment unit 1 succeeds in establishing a connection satisfying the requested bandwidth in step 102, the process branches to "Yes" in step 102, and the one-to-N type corresponding to the connection successfully established is established. After updating the entry in the connection table 3 (step 105), the process ends.

On the other hand, if the connection opening unit 1 fails to open a connection that satisfies the requested bandwidth in step 102,
"o", and the connection establishment control unit 2 sends a connection establishment request having a difference (increase) between the requested band and the currently used band to the connection establishment unit 1 (step 103). .

If the connection opening unit 1 succeeds in opening a connection having the increased bandwidth in step 103, the process branches to "Yes" in step 103,
Each item of the connection ID and the bandwidth of the corresponding session ID is added to the one-to-N connection table 3, and the number of connections corresponding to the session ID is increased by "1" (step 106), and the process is terminated. .

On the other hand, if the connection opening unit 1 fails to open a connection having the increased bandwidth in step 103, the "No"
After returning to the request source via the connection establishment control unit 2 (step 104), the process is terminated.

As described above, when the connection that satisfies the requested bandwidth is established and the delivery of the data packet is started, the data packet delivered from the node 12 is passed to the delivery connection determining unit 6 with the packet distribution function. It is. Delivery connection decision unit 6 with packet diversion function
Determines the connection to be delivered corresponding to the session ID to which the packet belongs with reference to the 1: N connection table 3.

At this time, if the number of connections to be delivered is "2" or more, packets are sorted according to the bandwidth ratio of the plurality of connections to be delivered. The packet whose distribution destination is determined is transmitted to the cell conversion unit 7.
To be decomposed into cells. The header of the disassembled cell includes a connection I to which the packet is delivered.
D is added. After that, the disassembled cells are
The packet is distributed via the connection 14 and the connection 15 on the M network,
At 1, the cell is reassembled into a packet. The reconstructed packet is stored in the packet buffer 10.

FIG. 3B is a flowchart for explaining the operation at the time of connection integration processing in the ATM network communication system shown in FIG. When the periodic signal from the timer 5 is input to the connection integration unit 4, the connection integration unit 4 checks whether or not the number of connections for each session ID in the one-to-N connection table 3 is "2" or more. (Step 20
1).

In step 201, if the number of connections is "1", there is no need to integrate the connections, so the process branches to "No" in step 201 and ends. On the other hand, if the number of connections is “2” or more, the process branches to “Yes” in step 201, and a connection having a total bandwidth of the connections corresponding to the session ID is opened, that is, the connection is established. The integration is requested to the connection opening unit 1 (step 202).

If the integration of the connection is successful in step 202, "Yes" in step 202
After the entry is updated in the one-to-N connection table 3 (step 203), the processing is terminated. On the other hand, if the connection integration fails in step 202, the process branches to "No" in step 202 and ends.

When there are a plurality of sessions in which the number of connections is “2” or more in the one-to-N type connection table 3, the processing of the above steps 201 to 203 may be repeatedly executed.

As described above, by periodically executing the integration process for integrating a plurality of divided connections,
An increase in the number of connections can be suppressed, and the burden of connection management in the ATM network can be reduced.

While the embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, but includes various embodiments according to the principle of the present invention.

[0056]

As described above, according to the ATM network communication system of the present invention, a plurality of connections are allocated to one session to increase the available bandwidth limit. A connection having a band exceeding the upper limit of the band on a single path can be opened.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of an ATM network communication system of the present invention.

FIG. 2 is a diagram conceptually illustrating the principle or operation of the ATM network communication system of the present invention.

FIG. 3 is a flowchart for explaining the operation of one embodiment of the ATM network communication system of the present invention. (A) shows the operation when a bandwidth change request is made, and (B) shows the operation at the time of connection integration processing.

FIG. 4 is a diagram showing the contents of a connection table used in one embodiment of the ATM network communication system of the present invention.

FIG. 5 is a configuration diagram showing an example of a conventional ATM network communication system having a communication band changing function.

FIG. 6 is a flowchart illustrating an operation when a bandwidth change request is made in a conventional ATM network communication system.

FIG. 7 is a diagram showing the contents of a connection table used in a conventional ATM network communication system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Connection opening part 2 Connection opening control part 3 1-to-N type connection table 4 Connection unifying part 5 Timer 6 Delivery connection decision part with packet diversion function 7 Celling part 8 Connection opening part 9 1-to-N type connection table 10 Packet buffer 11 Packetization unit 12, 13 Node 14, 15 Connection 16 Connection control unit 17 Data transmission unit 18 Connection control unit 19 Data reception unit 20 ATM network 21 Connection opening unit 22 One-to-one connection table 23 Delivery connection determination unit 24 Cell conversion unit 25 connection opening unit 26 one-to-one connection table 27 packet buffer 28 packetizing unit 29, 30 node 31 connection 32 connection control unit 33 data transmission 34 the connection control unit 35 data reception unit 36 ATM network 51 nodes 53, 54 ATM switch 55, 56 path 57 ATM network

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04L 12/28 H04L 12/56

Claims (6)

(57) [Claims] 1. An ATM network communication system having a function of changing a bandwidth of an ATM network connection comprising a plurality of ATM switches and a plurality of ATM nodes, wherein a bandwidth change request for an existing connection on the ATM network is provided. Fails on a given single path,
A connection having an increased bandwidth is opened on another path, and a packet is divided between the existing connection and the connection having the increased bandwidth, thereby setting the connection having the requested bandwidth. An ATM network communication system for improving a success rate. 2. The ATM network communication system according to claim 1, wherein said packet is diverted according to a bandwidth ratio between said existing connection and a connection having said increased bandwidth. 3. The ATM network communication system according to claim 1, wherein said packets are diverted in accordance with the amount of untransmitted packets in a transmission buffer managed for each connection. 4. The ATM network communication system according to claim 1, wherein an integration process of the plurality of connections into which the packet is diverted is executed at predetermined intervals to suppress an increase in the number of connections. 5. The ATM network communication system according to claim 2, wherein an integration process of the plurality of connections to which the packet is diverted is executed at predetermined intervals to suppress an increase in the number of connections. 6. The ATM network communication system according to claim 3, wherein an integration process of the plurality of connections to which the packet is diverted is executed at predetermined intervals to suppress an increase in the number of connections.