KR0132952B1 - Communication method using mask table and marker tible of - Google Patents

Abstract

The present invention relates to a communication method using a mask table and a marker table in a ring-type ATM communication network, and in particular, a first step of determining whether a node is included in a multicast communication group when receiving a multicasting cell; In the first step, if the node is not included in the multicast communication group, the cell is transmitted to the next neighbor node using a marker table. If the node is included in the multicast communication group, the cell is transmitted. A second step of transmitting to the physical layer and the ATM processing unit 11 and determining whether the node is located at the end of the communication group by using a mask table; In the second step, if the node is located at the end of the communication group, the cell is deleted. If the node is not located at the end of the communication group, the cell is transmitted to the adjacent node using a marker table. Through the third step, the subscriber is classified using the mask table and the marker table, and the cells received at each ring node are processed accordingly, thereby realizing a simple and high-speed communication method in a ring-type ATM communication network. .

Description

Communication Method Using Mask Table and Marker Table in Ring-type ATM Network

1 is a structural diagram of an ATM communication network having a ring structure to which the present invention is applied, FIG. 2 is a structure of a ring cell for internal communication between ring nodes, and FIG. 3 is an explanatory diagram illustrating a DNID and ONID allocation scheme in a one-to-one connection. 4 is an explanatory diagram illustrating a DNID allocation method in multicasting, FIG. 5 is a flowchart of a multicasting cell processing method of an inner ring communication processing unit, FIG. 6 is an exemplary diagram of a mask table used in the cell processing method of FIG. 7 is an explanatory diagram showing a logical connection relationship between an input port and an output port of a ring node, and FIG. 8 is a flowchart of a method for generating a marker when a cell is input from a physical layer and an ATM processor in a one-to-one access cell, and FIG. 9 is a flowchart illustrating a method of generating a marker when a cell is input from an external interface in a one-to-one access cell, and FIG. 10 is an explanatory diagram illustrating a multicasting generation and release process.

* Explanation of symbols for main parts of the drawings

10: ring node system 11: physical layer and ATM processing unit

12: internal ring communication processing unit

The present invention relates to a communication method using a mask table and a marker table in a ring-type asynchronous transfer mode (ATM) network, and particularly, a mask table while using a method of erasing a cell from a destination node in a ring-type ATM network. And a communication method for realizing a point-to-point connection, multicasting, and broadcast service using a table and a marker table.

Unlike a point-to-point communication network structure, in a ring-structured communication network, all traffic is connected to the same ring. As the traffic volume of a user increases, a network device may become a bottleneck in the entire communication network. Therefore, the method to increase the efficiency of network link should be considered. The same problem occurs in a ring-type Asynchronous Transfer Mode (ATM) network, which is frequently applied to a subscriber access network or a private network of a broadband integrated services digital network (B-ISDN). The ring will continue to cycle unless it is cleared.

In general, there are two methods of erasing a cell: a method of erasing a cell at a transmitting node and a method of erasing at a called node. In case of erasing a cell from a transmitting node, it can be performed without a separate message (eg, ACK / NACK) about whether the corresponding cell has been received without error on the destination node, and can easily provide fairness between ring nodes. There is an advantage. On the other hand, when the cell is deleted from the destination node, careful attention is required to maintain fairness between nodes, and a separate protocol for ACK / NACK message is required. However, as the communication line becomes faster and the propagation delay becomes a major factor of the total cell delay, the performance of the entire communication network can be greatly improved when the destination node erases the cell.

Accordingly, the present invention provides a point-to-point connection, multicasting, and broadcast service using a mask table and a marker table while using a method of erasing a cell from a destination node in a ring-type ATM communication network. It is an object of the present invention to provide a communication method using a mask table and a marker table in a ring-type ATM communication network.

In order to achieve the above object, the present invention provides a physical layer and ATM processing unit for performing four physical layer interface functions, ATM cell processing, multiplexing and demultiplexing, and cell exchange and copy functions. And an inner ring communication processor configured to route the ATM cell transmitted from the processing unit to another ring node, and to receive the ATM cell received from the other ring node to its own physical layer and ATM processing unit or to relay to an adjacent ring node. A communication method applied to a ring-type ATM communication network, comprising: a first step of determining whether a node is included in a multicast communication group when receiving a multicasting cell; In the first step, if the node is not included in the multicast communication group, the cell is transmitted to the next neighbor node using a marker table, and if the node is included in the multicast communication group, the cell is transmitted. A second step of determining whether a node is located at the end of a communication group by using a mask table after transmitting to a physical layer and an ATM processor; In the second step, if the node is located at the end of the communication group, the cell is deleted. If the node is not located at the end of the communication group, the cell is transmitted to the adjacent node using a marker table. A communication method using a mask table and a marker table in a ring-shaped ATM communication network comprising a third step.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an ATM communication network having a ring structure to which the present invention is applied. The ATM communication network uses an inner ring, each of which has four external interfaces (for example, a subscriber device and a network device interface), a physical layer and an ATM. It consists of four ring node systems 10 having a processing unit 11 and an inner ring communication processing unit 12.

The physical layer and the ATM processor 11 perform four physical layer interface functions, ATM cell processing, multiplexing and demultiplexing, and cell exchange and copy functions.

The inner ring communication processing unit 12 routes the ATM cell delivered from the ATM connection and processing unit 11 to another ring node, and transfers the ATM cell received from the other ring node to its own physical layer and ATM processing unit 11. ) Or relay to an adjacent ring node.

2 shows the structure of a ring cell for internal communication between ring nodes.

The inner ring communication processing unit 12 is a module for realizing communication between ring nodes through the inner ring, and communication between ring nodes is achieved by transmitting / receiving a ring cell between the inner ring communication processing units 12, and the ring cell is shown in FIG. Have the same structure. Where R is ring identifier, CT is connection type, DNID is destination node identifier, ONID is raw node identifier, CNID is Corresponding node identifier, PT is payload type, CLP is cell discard priority, HEC is Show head error correction respectively.

The ring cell structure is the same as the ATM cell structure for the high speed implementation of the system and the effective ATM cell transmission / reception, and the GFC and VPI (Virtual Pass) of ATM cells can be used to distinguish and route connections through the inner ring between ring nodes. Only part of the Identifier field and the Virtual Channel Identifier field are used. Therefore, the payload type (PT) and cell discard priority (CLP) can be used for cell communication and operation management in the ring.

Two bits of R are used to select a ring when there is more than one internal communication ring, or to designate a communication group when there is more than one logical communication group through the ring. A two-bit CT is used to distinguish which type of cell is one-to-one ('00'), broadcast ('11'), or multicasting ('01') connection. Four bits of DNID, ONID, and CNID are used to indicate the destination and origin of the ring cell and the external interface participating in the multicasting connection, which is used to route, erase, and select the ring cell.

FIG. 3 is a diagram illustrating a DNID allocation method for ONID and one-to-one access service.

When the four bits that make up the ONID are marked as 'y1y2y3y4' and the four bits that make up the DNID are marked as 'x1x2x3x4', 'y1y2' and 'x1x2' are used to distinguish the sending and receiving nodes, respectively. 'y3y4' and 'x3x4' are used to distinguish the four external interfaces connected to each node. In this case, the CNID is used to distinguish a plurality of sessions that may occur between subscribers selected by the ONID.

4 is a diagram illustrating a DNID allocation method in the case of a multicast service.

In this case, the DNID only specifies the node that contains the subscriber included in the multicasting. That is, when the subscriber connected to the node whose ID is i is included in the multicasting service, the xi + 1 bit becomes 1. In FIG. 4, the subscriber related to the multicasting service is indicated by '●'. At this time, nodes including subscribers belonging to the multicast communication group are '00', '01', and '11'. Therefore, in this case, the DNID is assigned a value of '1101'.

The node receiving the cell using the DNID value transmits the cell to the external interface using the CNID value. When multiple subscribers are involved in the multicasting service in a node, the cell is duplicated and transmitted to each external interface. Detailed description thereof will be described later. In the case of a broadcast service, a DNID has no meaning because a cell must be delivered to all nodes.

5 is an operation flowchart of the multicasting cell processing method of the inner ring communication processor 12. In each node, whether or not to receive a cell transmitted from an adjacent node and whether or not to delete the cell is returned to the adjacent node. It shows the algorism of whether to deliver.

When the delivered cell is a one-to-one access service and broadcast, it is easily determined that the cell is erased from the ring. That is, in the case of one-to-one access service, the receiving node may delete the cell after receiving it, and in the case of broadcasting, the transmitting node may delete the cell.

6 is a mask table used for a multicasting cell in the cell selection and erase algorithm operation. Here, ONID = y1y2y3y4, DNID = x1x2x3x4, and the node ID is displayed as own-ID.

If the transmitted cell is a multicasting cell, that is, CT = 01, if its node is included in the multicast communication group, the cell is transmitted to the physical layer and the ATM processing unit 11, and then the node of the node is the communication group. If the group is located at the end of the cell, the cell is erased. Otherwise, the cell is deleted. If the node is not included in the communication group, the cell is simply transmitted to the next neighbor node. In order to erase a cell, a method for determining whether its own node is the last node in a communication group is needed. This method is performed by using an algorithm as shown in FIG. 5 after obtaining a mask value from the mask table shown in FIG. 6 using y1y2 of the ONID and its node ID as indes.

The cell delivered to the physical layer and the ATM processor 11 must be transmitted to the actual subscriber. That is, it must be sent to one or many of the four external interfaces. Cells from external interfaces must also be sent to other nodes or rings on their nodes. Therefore, the physical layer and the ATM processing unit 11 require a kind of switch function. When the external interface is represented by C1, C2, C3, and C4, the physical layer and the ATM processor 11 are represented by PM, and the inner ring communication processor 12 is represented by RM, each cell is inputted. The logical relationship with each output port from the port is shown in FIG.

FIG. 7 is a diagram illustrating a logical connection relationship between an input port and an output port of a ring node.

The marker (M) of the output port to which the cell should be transmitted from each input port is composed of four bits of 'm1m2m3m4', which indicates that the cell should be output to the first output port when mi is '1'.

For example, in FIG. 7A, if m4, m3, m2, m1 = 1, 0, 1, 1, cells from the physical layer and the ATM processor 11 are simultaneously connected to the external interfaces of C1, C2, and C4. Output, but not sent to the C3 external interface. Thus, the operation of this switch depends on how to create a marker for each service.

When the input cell is a one-to-one access service, the method of generating a marker differs depending on the case where the input port is an external interface and the case of the physical layer and the ATM processor 12.

8 illustrates a method of generating a marker when input from a physical layer and an ATM processor.

9 illustrates a method of generating a marker when the input port is an external interface.

When the input cell is for broadcasting, the input port should always be markers m4, m3, m2, m1 = 1, 1, 1, 1, regardless of whether the input port is an external interface or the physical layer and the ATM processor 11. That is, cells must be sent to all output ports.

However, if the input cell is for multicast, the cell should be transmitted to an output port included in the multicast group. At this time, the multicasting call is distinguished by ONID and CNID. Therefore, the marker can be obtained from the marker table created at the time of multicasting call setup using ONID and CNID as indexes.

10 is a diagram illustrating a multicasting call generation and release process. The generation of the marker table necessary for the switching of the multicasting cell uses the DNID, ONID and CNID of the ESTABLISH message transmitted during the generation process. If the ESTABLISH message has an ONID, CNID pair that does not exist in the table, the message arrives first among the messages for that group, so add a marker with the marker bit corresponding to the DNID of the message set to 1. .

For the message having the ONID and CNID pairs present in the table, the marker bit corresponding to the DNID is set to 1 for the marker corresponding to the ONID and CNID pairs.

As the call is released, the table entry no longer has any meaning. When the call is released, the corresponding record in the table is deleted by the REMOVE message.

For example, consider a case in which C2 connected to node '00' having node ID '0001' sends multicasting call generation requests in order from nodes such as 0011, 0101, 0110, 1100, and 1111. It is assumed here that CNID = '0000' is determined.

The ring node with the address of '00' checks the first transmitted DNID = 0011, ONID = 0001, and establishment of CNID = 0000 (ESTABLISH) message. Add entries 0001, 0000, 1000.

Then, the next message DNID = 0101, ONID = 0001, and CNID = 0000 is examined. The upper two bits of the DNID of this message are different from their IDs, so they are sent to the inner ring communication processor. Find the entry with the CNID '0000' and set the mask bit.

That is, the entries of 0001, 0000, and 0010 that are created first are changed to 0001, 0000, and 0110.

The present invention proposes a communication scheme for one-to-one connection, multicasting, and broadcasting by setting the number of nodes connected to a ring node and the number of external interfaces connected to each node to 4, respectively, and the number of arbitrary external interfaces and ring nodes. In order to apply a multicast scheme in a communication network having a number, a case of adjusting the number of bits of a DNID or coding a DNID using a specific coding method corresponds to a modification of the present invention.

As described above, the present invention distinguishes subscribers using a mask table and a marker table, and processes cells received at each ring node accordingly, thereby simplifying communication in a ring-type ATM communication network and enabling high-speed processing. It can be realized.

Claims (1)

It is transmitted from the physical layer and ATM processing unit 11 and the ATM access and processing unit 11 that perform four physical layer interface functions, ATM cell processing, multiplexing and demultiplexing, and cell exchange and copy functions. Inner ring communication processing unit 12 for routing the ATM cell to the other ring node of interest and receiving the ATM cell received from the other ring node to its own physical layer and ATM processing unit 11 or relaying to the adjacent ring node. A communication method applied to a ring-type ATM communication network, comprising: a first step of determining whether a node is included in a multicast communication group when receiving a multicasting cell; In the first step, if the node is not included in the multicast communication group, the cell is transmitted to the next neighbor node using a marker table. If the node is included in the multicast communication group, the cell is transmitted. A second step of transmitting to the physical layer and the ATM processing unit 11 and determining whether a node is located at the end of the communication group by using a mask table; In the second step, if the node is located at the end of the communication group, the cell is deleted. If the node is not located at the end of the communication group, the cell is transmitted to the adjacent node using a marker table. A communication method using a mask table and a marker table in a ring-shaped ATM communication network comprising a third step.