KR0150529B1 - Communicationless server system having selective multicasting function - Google Patents

Abstract

The present invention relates to a selective multicasting function configuration in a connectionless server in an ATM (Asynchronous Transfer Mode) network, comprising: cell division means for dividing an input cell into a data cell and an OAM cell or a control cell; Cell copying means for receiving a multicasting cell having a group address value and performing a multicasting function; OAM processing means for processing the OAM cell input from the cell discriminating means; Connection control means for processing a control cell input from said cell discriminating means; Header conversion and DA processing for converting a VIP / VCI / MID value according to a destination address (DA) of a data cell inputted from the cell discriminating means and providing the cell copying means, the OAM processing means and the connection control means. Way; And a cell discrimination and multiplexing means for receiving the outputs of the cell copying means, the OAM processing means and the connection control means, separating the multicasting cells, feeding them back to the cell copying means, and multiplexing the data cells and the multicasting and control cells. Features can optionally have multicasting capabilities.

Description

Connectionless server system with optional multicasting capability

1 is a configuration diagram for providing a connectionless data service in an ATM network.

2 is a diagram illustrating a multicasting function in a connectionless server.

3 is a block diagram of a connectionless server system according to the present invention.

4 is a diagram illustrating a header conversion process in a connectionless server according to the present invention.

5 is a diagram illustrating a group address and a group address cell processing according to the present invention.

6 is an output cell format diagram of a header converter according to the present invention.

7 is an explanatory diagram of a cell copying process according to the present invention.

8 is an explanatory diagram of a cell duplication process according to the present invention.

* Explanation of symbols for main parts of the drawings

31: destination address (DA) processing unit 32: header conversion unit

33: cell separator 34: cell separator and multiplexer

35: OAM processing unit 36: connection control unit

37: cell copy unit 38: CRC-10 generator

The present invention relates to a connectionless server system having an optional multicasting function in an asychronous transfer mode (ATM) network.

The conventional multicasting server system is applied to an ATM switch. In a switch having M inputs and N outputs, M-2 has as input ports, N-1 as output ports, and one transfer port. It has a primary header converter and a secondary header converter with input and output terminals for multicasting.

Header converters act as chainers and distributors, respectively. Input terminals of the connector and the distributor are respectively connected to the transmission port of the switch to receive data for multicasting.

When data cells to be routed to a number of different addresses are received at an input port on an address according to a connection identifier (VPI / VCI), an indication is made on the switch to allow the cells to be routed to the transport pod. The transport port is connected to two header converters, one of the two header converters is a chainer, and the other is a distributor.

For multicasting, data cells routed from one of the switch's input ports to the transport port are simultaneously entered into the chainer and the distributor. However, even if the data cells are simultaneously input to the chainer and the distributor, the data cells for multicasting are identified by the chainer according to the address of the cell.

The chainer modifies the address indicated by the link identifier (VPI / VCI) and transmits it to the transport port through the input terminal of the switch together with the data cell and inputs it back to the chainer and the distributor. The chainer then creates a newly modified address, and the distributor recognizes the modified address, changing the routing indication and the link identifier (VPI / VCI) so that the data cell has one output at the input of the switch. To be sent to the port.

The CHAINER operates in feedback mode to generate a series of addresses having a form that the distributor can recognize. This operation continues until it generates a final address that indicates an unrecognized termination when fed back.

The Distributor operates to create an address indicator and translate the connection identifier (VPI / VCI) for each address, and with each address indicator to place the data cell through the switch's input terminal in an appropriate location on the switch's output port. To route.

As described above, a conventional multicasting server system includes two header converters in a device by adding a multicasting device to a switch, and one of the two header converters performs address translation according to an individual address belonging to a group address, and the other. As a result, the device has a disadvantage in that the device is complicated and the copying function according to the feedback must be made as well as the last address in the group address is generated.

Therefore, the present invention devised to solve the problems of the prior art as described above does not have a multicasting function when the sender wants to transmit the same information to multiple receivers at the same time by using a copy of one cell through multicasting. The server treats the CLNAP-PDU (ConnectionLess Network Access Protocol-Protocol Data Unit) with group addresses the same as the CLNAP-PDU with individual addresses, and allows only a few servers in a network with multiple connectionless servers. Optional multicasting function that allows the server to process CLNAP-PDUs with group addresses in the same way as CLNAP-PDUs with individual addresses, when multicasting functions do not exist within the server and as separate devices. The purpose is to provide a connectionless server system having a.

The present invention for achieving the above object, Cell division means for analyzing the input cell and outputting divided into a data cell, an operation management (OSM) cell and a control cell; OSM processing means for processing the OSM cell input from the cell discriminating means; Connection control means for performing connection control according to a control cell inputted from the cell classification means; The header value of the data cell inputted from the cell discrimination means is converted into an output virtual connection identifier (VPI), a virtual channel identifier (VCI), a multiplex identifier (MID), and a multicasting indication (MI) value according to a destination address. Destination address header converting means; Cell copying means for receiving a multicasting cell having a group address value and copying the cell; If the data cell inputted from the destination address header converting means is not a multicasting cell, it is outputted by multiplexing with the OSM cell and control cell inputted from the OSM processing means and the connection control means, and the data inputted from the destination address header converting means. Cell discrimination and multiplexing means for outputting to the cell copying means when the cell is a multicasting cell and multiplexing with the OAM cell and the control cell inputted by the OAM processing means and the connection control means when a cell copy is made; And a CRC generating means for performing a cyclic redundancy check on a cell inputted from the cell division and multiplexing means, and then adding and outputting a cyclic redundancy check (CRC) value.

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

1 is a block diagram for providing a connectionless data service in an ATM network. The ATM network 13 having an ATM switching function 11 such as an ATM switch and a connectionless server (CLS) 12, a user LAN via a network consisting of an Interworking Unit (IWU) 14 connected to an ATM network via a User Network Interface (UNI) and a plurality of Local Area Networks (LAN) 15 connected to the IWU. Traffic generated at 15 is transferred to the other LAN 15 through a virtual connection established between the IWU 14 and the connectionless 12.

The IWU 14 transmits the traffic generated from the LAN 15 to the connectionless server 12 through a virtual connection established between the IWU 14 and the connectionless server 12.

The connectionless server (CLC) 12 performs routing according to the destination address value of the connectionless data inputted from the subscriber, where the connectionless data service subscriber encapsulates the data into a CLNAP-PDU and delivers it to the CLS 12. In the CLS 12, routing is performed according to the destination address.

In this structure, for the multicasting function, there is an area in the form of address indicating a group address or an individual address in the destination address, and the connectionless server (CLS) 12 copies the CLNAP-PDU having the group address value and belongs to the group. Deliver to subscribers of individual addresses.

2 shows an example of performing a multicasting function in a connectionless server.

Not all servers need to have a multicasting function. If the transmitting terminal A 21 sends a CLNAP-PDU having a group address, the CLSI 22 having no multicasting function bypasses the CLNAP-PDU to perform the multicasting function. CLS4 (23) to transmit.

The Group Address Agent (GAA) 212 in the CLS4 (23) with multicasting function includes a cell copying unit and a group address control unit, and searches an address table using a group address in a CLNAP-PDU. do. The group address GA then knows that it should be delivered to the individual addresses of terminals A 21 / B 24 / C 25 / D 26 / E 27.

The GAA 212 then duplicates and transmits the CLNAP-PDUs having individual addresses to the terminals B 24 and C 25 belonging to the CLS2 29 without the multicasting function, except for the transmitting terminal A 21. do. In addition, the CLS4 210 having a multicasting function transmits a CLNAP-PDU having a NES (Nested Group Address) having a terminal D 26 and an E 27 as an element, and a CLS3 ( 210 analyzes the resolution of the group address included in the NGA, and duplicates and transmits the CLNAP-PDU having the individual address to the terminals D 26 and E 27.

In the connectionless server, group address generation, removal and modification are performed by the GAA (Group Address Agent 212), thereby handling the CLNAP-PDU having the group address. The GAA 212 is the NGAA to increase the processing efficiency. (Nested Group Address Agent) 211 can be created, which is responsible for the copy function.

As such, the connectionless service for the connectionless data service should be able to deliver the group address message to another connectionless server having the multicasting function or to selectively transmit the multicasting function to its own multicasting function.

That is, a connectionless server can optionally have a multicasting function, so a server without a multicasting function treats a CLNAP-PDU having a group address in the same manner as a CLNAP-PDU having an individual address, and processes a plurality of connectionless servers. If only some servers in the network have multicasting functions, or if the multicasting function does not exist in the server and exists as a separate device, the server uses the CLNAP-PDU with the group address as the CLNAP-PDU with the individual address. Can be processed as

3 is a block diagram of a connectionless server system according to the present invention, in which 31 is a destination address (DA) processor, 32 is a header converter, 33 is a cell separator, 34 is a cell separator and multiplexer, 35 denotes an OAM processing unit, 36 a connection control unit, 37 a cell copy unit, and 38 a CRC-10 generation unit.

The connectionless server system includes a destination address (DA) processor 31, a header converter 32, and a data cell for converting a VPI / VCI / MID value from a cell input from an ATM network to a destination address value. A cell separator 33 for dividing and outputting an OAM cell or a control cell, a multi-casting cell, a cell separator and a multiplexer 34 for multiplexing a data cell, a multicasting cell and a control cell, and outputting a CRC. CRC-10 generating unit 10, the OAM processing unit 35 for processing the network management cell (OAM) among the cells input to the server, the connection control to receive the control cell and perform the connection control of the input cell (Connection Control Unit 36, and a cell copy unit 37 for receiving a cell having a group address value and copying and outputting the cell.

The cell separator 33 searches for a connection identifier (VPI / VCI) among the inputted cells and receives an error through a CRC-10 check on a cell payload of a cell having a virtual connection number that is not already set and a cell having a set virtual connection number. Remove the cell where it occurred.

The OAM cell, which is a cell for transmitting network management information of the CLS 12, among the cells in which no error occurs, is transmitted to the OAM processing unit 35, and in the case of a control cell, the connection control unit 36. The data cell is outputted to the header converter 32 and the destination address processor 31.

The OAM processor 35 receives an OAM cell from the cell separator 33, processes the OAM cell, and outputs the OAM cell to the cell separator and multiplexer 34. The connection controller 36 inputs a control cell from the cell separator 33. The destination address processor 31 is controlled, and the control cell is output to the cell division and multiplexer 34.

The destination address (DA) processor 31 receives the destination address value extracted from the data cell, analyzes it under the control of the connection control unit 36, and analyzes the same, and then, if the cell has an individual address, the header value of the cell. Is converted into a connection identifier (VPI / VCI) set between the destination and the server, and is stored in a non-connected server (CLS), in the case of a cell having a group address with a multicasting function. For the cell to be delivered to the connected server (CLS), the header value of the cell is converted into a virtual connection identifier (VPI / VCI) set between the destination and the connectionless server (CLS), and stored, and multicasted to the connectionless server (CLS). In the case of a cell having a group address with a function, the cells to be duplicated in the CLS among the cells having the group address can be inputted and output as individual addresses included in the group address. To convert a header value to be stored in a table.

At this time, the cell type with the group address is displayed by setting the arbitrary bit of the header error check (HEC) field of the cell to 1, and the HEC field is not used in the connectionless server (CLS). To indicate a group address.

The header converter 32 extracts the header value from the data cell input by the cell separator 33, and then retrieves the header value converted and stored by the destination address processor 31 from the table using the header value as an index value. After converting the header into the header value, the data cell is outputted to the cell separator and multiplexer 34.

The cell division and multiplexer 34 outputs the cell copy unit 37 if the data cell input from the header converter 32 is a multicasting cell, and the OAM cell input from the OAM processing unit 35 if the cell is not a multicasting cell. And multiplex the data cells together with the control cells input from the connection control unit 36 and output them to the CRC-10 generating unit 38. Further, the cell copied by the cell copying unit 37 and the OAM cell and the control cell are multiplexed and outputted to the CRC-10 generating unit 38.

The CRC-10 generator 38 performs a Cyclic Redundancy Check (CRC) on the cells input from the cell division and multiplexer 34, and then adds a CRC value to the destination.

As described above, the connectionless data service subscriber in the B-ISDN transmits data to the CLS by encapsulating the CLNAP-PDU, and the connectionless server performs routing according to the destination address value of the connectionless data input from the subscriber. Perform.

The connectionless server defines the group address value at the destination address for multicasting. The connectionless server copies the CLNAP-PDU with the group address value to the subscriber of the individual address in the group.

Such a function performs copying and header conversion on a cell basis, but it is preferable that a multicasting function that simplifies processing functions by continuously processing cells constituting one CLNAP-PDU is implemented in a connectionless server.

4 is a view for explaining a header conversion process in a connectionless server according to the present invention, the header converter 32 receives a data cell from the cell separator 33, the destination address processor 31 is a cell separator The destination address extracted from the data cell inputted from the unit 33 is inputted, and among the header values of the input message start (BOM) / signal segment message (SSM) cell, a virtual path identifier (VPI), a virtual channel identifier (VCI), and a MID. Multiplexing Identifier is stored in the header mapping table 41.

The destination address processor 31 receives the destination address and stores the output VPIo / VCIo / MIDo / MIo in the header mapping table 41 under the control of the connection controller 36.

The header converting unit 32 searches for a header mapping table 41 by using the VPI / VCI / MID of the input data cell as an index key and corresponds to the header mapping table 41.

After reading the VPIo / VCIo / MIDo / MIo value, the data cell is output by replacing the header value of the data cell with this value.

In this case, the MI (Multicasting Indication bit) is a value indicating whether the cell is to be duplicated in the cell copy unit 37 in the server, and uses any bit in the HEC field of the cell header. At this time, the header converting unit 32 converts the header when a message ending (EOM) / signal segment message (SSM) cell indicating the end of the message is input, and then removes data related to the cell from the header mapping table 41. Let's do it.

The destination address processor 31 provides a channel number of the virtual connection between the destination and the connectionless server (CLS), and allocates a MID value and an MI value for a message to be transmitted through the virtual connection.

Therefore, the cell header conversion in the header converter 32 should be performed after the VPIo / VCIo / MIDo / MIo values of the message including the cell are completely stored in the header mapping table 41.

FIG. 5 is a diagram for explaining group address and group address cell processing according to the present invention, which is processed in the same manner for a CLNAP-PDU having a group address.

When the group address is input, the DA_ID of the destination address is output from the destination address identifier (DA_ID) table 51 of the destination address processor 31, and the CO_ID is output according to the DA_ID output from the destination address identifier table 51. (Connectio

n_Identifier) table 52 outputs CO_ID.

The multiplexing identifier (MID) generation unit 53 sets the MID to a specific value based on the CO_ID value output from the CO_ID table 52.

In the VIP / VCI table 54, the CLNAP-PDU having a group address is set to a multicasting bit fmf '1' and stored in the header mapping table 41.

In this case, a specific value (for example, VPI = k) indicating a cell having a group address is allocated to the VPI area, and the VCI area is used as a group address identifier (GA_ID: Group Address_Identifier) corresponding to the group address value.

Through this, the connectionless server (CLS) may determine whether the cell is a group address cell by looking at the VPI region of the input cell, and determine which cell belongs to the CLNAP-PDU having a destination address of the value from the VCI region.

When CLNAP-PDUs with the same group address are input from different subscribers, MID values are assigned in the same way as with individual addresses, even if the CO_ID value corresponding to the group address is entered. Therefore, the cells constituting the CLNAP-PDU can be distinguished using the VCI and MID values.

The cell separator 55 has a specific value indicating that the VPI is a cell having a group address when the MI bit of the data cell input from the header converter 32 is set to 'I', and the group address is included in the VCI area. Since GA_ID is assigned, the cell copy is made through the cell copy unit 37 using the GA_ID corresponding to the group address in the VCI area, and then transmitted to the multiplexer 56. The cell separator 55 transmits the data cell directly input to the multiplexer 56 when the MI bit is set to '0'.

The multiplexer 56 multiplexes the group address cell, the individual address cell, the OAM cell, and the control cell, and outputs the result to the CRC-10 generator 38.

6 is a diagram illustrating an output cell format of a header converter, and uses a HEC (Header Error Check) field 61 of a cell header to indicate that the cell is a group address cell to be transmitted to the cell copyer 37.

Since the HEC field 61 is not used inside the server, it represents a group address using any of 8 bits of the HEC field 61 as a multicasting indicator bit. In FIG. 6, the first bit is MI. The example used as a bit is shown.

7 is an explanatory diagram of a cell copying process according to the present invention, which shows a process of copying a group address cell arrived at a CLS and delivering it to a destination of an individual address belonging to the group.

First, the cell is read from the Read FIFO 71 and if the VPI value of the cell is a multicasting cell, the VCI and MID values are checked and stored in the message queue at the corresponding location.

This message queue is a queue that temporarily stores until all cells constituting one CLNAP-PDU arrive. When a message start cell (BOM) constituting a new CLNAP-PDU arrives, a new queue is allocated and continuously entered. Cells having the same VCI / MID value are stored, and when the message end cell (EOM) arrives, all cells are delivered to the cell replicator 72 and the queue is removed.

The cell replicator 72 outputs the copied cell to a write (WR) packet (FIFO) 73.

In this case, the multicasting function performs copying and header conversion on a cell basis, but the processing function can be simplified by continuously processing cells constituting one CLNAP-PDU.

8 is a diagram illustrating a cell duplication process according to the present invention.

The input cell is stored in the copy register 83, the group address identifier (GA_ID) is searched for the group address (GA) index table 81 by using the key to obtain the GA table address, and the VPI of the mapping table according to the GA table address. / VCI is stored in the header of the input cell, the object address value is stored in the destination address area if the segment type (ST) of the input cell is a BOM / SSM cell, and the MID value is used in the header converter 32 Is converted to a specific value that is not passed.

Many group address identifiers (GA_IDs) are supported, of which certain values can be used for broadcasting to all subscribers in the server. The rest is used for multicasting. The maximum number of individual addresses that a GA_ID can have is variable.

The group address table 84 has, for each group address, an individual address value of all terminals belonging to the group address and a VPI / VCI value corresponding to the address.

Therefore, read the VPI / VCI value and the individual address value from the first entry in the group address table and write it to the VPI / VCI and address fields of the copy register (including AT section: AT = 1100) and then in the copy register. Send the cell.

The cell replication is repeated until the last entry in the group mapping table 82. VPI / VCI is written regardless of the cell type, but the address value is written only if the cell type is BOM / SSM, otherwise writing is not possible. It doesn't work.

In this way, the server assigns a single group address to a set of individual addresses composed of several different individual addresses, and removes or, if necessary, performs a group address creation / delete / change function.

That is, the multicasting of the present invention as described above can transmit the same information to multiple receivers at one time, which is much more efficient than individually transmitting cells of the same information to multiple subscribers.

Therefore, the present invention can selectively have a multicasting function and has the effect of configuring a flexible connectionless server that can be applied in various cases as shown in FIG.

Claims (5)

Cell dividing means for analyzing the input cell and dividing the input cell into a data cell, an operation management (OAM) cell, and a control cell; OAM processing means for processing the OAM cell input from the cell discriminating means; Connection control means for performing connection control according to a control cell inputted from the cell classification means; A destination address for outputting a header value of a data cell inputted from the cell distinguishing means as a value of a virtual connection identifier (VPI), a virtual channel identifier (VCI), a multiplex identifier (MID), and a multicasting indication (MI) according to a destination address Header conversion means; Cell copying means for receiving a multicasting cell having a group address value and copying and outputting the cell; If the data cell inputted from the destination address header converting means is not a multicasting cell, the OAM cell and the control cell inputted by the OAM processing means and the connection control means are multiplexed and outputted, and the cell inputted from the destination address header converting means. A cell discrimination and multiplexing means for outputting to the cell copying means for the multicasting cell and multiplexing with the OAM cell and the control cell inputted from the OAM processing means and the connection control means when a cell copy is made; And a CRC generating means for performing a cyclic redundancy force on a cell inputted from the cell division and multiplexing capability, and then adding and outputting a Cyclic Redundancy Check (CRC) value. system. The method of claim 1, wherein the destination address header converting means extracts and stores a virtual connection identifier (VIP), a virtual channel identifier (VCI), and a multiplex identifier (MID) of a data cell inputted from the cell separator. A header mapping table for storing an output virtual connection identifier (VPI), a virtual channel identifier (VCI), a multiplexing identifier (MID), and a multicasting indication (MI) value; Receiving a destination address extracted from the data cell inputted from the cell discriminating means, the virtual connection identifier (VPI), virtual channel identifier (VCI), multiplexing identifier (MID) and multicasting according to the destination address are controlled by the connection control means. Destination address processing means for outputting an indication (MI) value to the header mapping table; And an output virtual corresponding to the header mapping table by searching the header mapping table using the index key of the virtual cell identifier (VPI), the virtual channel identifier (VCI), and the multiplex identifier (MID) of the input data cell. And a header converting means for receiving a connection identifier (VPI), a virtual channel identifier (VCI), a multiplexing identifier (MID), and a multicasting indication (MI) value, and converting and outputting a header value of a data cell. Connectionless server system with multicasting capability. 3. The header converting means according to claim 2, wherein the header converting means sets a random bit among 8 bits of a header error check (HEC) field of a cell not used in a connectionless server as a multicasting indication bit. Connectionless server systems with optional multicasting capabilities. 2. The apparatus of claim 1, wherein the cell copying means comprises: a read buffer buffering an input multicasting cell; Read the multicasting cell from the read buffer and temporarily store the cell in the corresponding location according to the VCI and MID values of the multicasting cell until all cells constituting one CLNAP-PDU (ConnectionLess Address Protocol-Protocol Data Unit) arrive. Message queue; Cell duplication means for receiving cells having the same VCI / MID value from the message queue and duplicating and outputting the cells; And a write buffer for buffering the output of the cell replicating means. 5. The apparatus of claim 4, wherein the cell duplication means comprises: a group address index table for storing a table address storing an individual address according to a group address and outputting a table address corresponding to a group address identifier; A plurality of group mapping tables storing individual addresses according to group addresses and outputting corresponding virtual connection identifiers (VPI / VCI) and individual addresses according to table addresses of the group address index table; And storing the input cell, writing the header of the cell as a virtual connection identifier (VPI / VCI) stored in the group mapping table, and writing the object address stored in the group mapping table to a destination address if the segment type indicates the beginning of the message. Connectionless server system having an optional multicasting function, characterized in that it comprises a copy register to output.