JPH0563725A - Multiplexing system for lap-b - Google Patents

Abstract

PURPOSE:To attain a LAP-B link to be multiplexed by providing a communication identifier management means with plural links assigned thereto to one terminal equipment of a terminal adaptor setting the LAP-B link between a network and a terminal equipment. CONSTITUTION:A caller terminal equipment 20 establishes a physical virtual communication line to transmission destination terminal equipments 21, 22 independently by a LAP-B link through a physical line 23 independently. A communication identifier management section 19 is provided to a terminal adaptor and the management section 19 manages the link state. The terminal adaptor 24 is provided with a terminal communication control section 25 implementing the communication with a terminal equipment, a LAP-B control section 26 establishing the LAP-B link and a B-ISDN communication identifier management section 27. The management section 27 manages the LAP-B link for ISDN communication corresponding to the communication destination terminal equipment. A driver section is provided with a terminal equipment and network driver for a terminal equipment and network 23, and a transfer control section is provided in a terminal equipment use driver and a B-ISDN communication identifier management section is provided in a network driver in a control layer at an upper layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal adapter for performing ISDN communication, and more particularly to a LAP-B multiplexing system for multiplexing LAP-B in B-ISDN.

[0002]

2. Description of the Related Art ISDN has been put into practical use and developed as a data transfer communication system capable of high-speed data communication.

The transfer procedure of narrow band ISDN (N-ISDN) is X. Twenty-five link level protocols are used. This protocol is called LAP-B (Concurrent Link Access Protocol). For example, with this LAP-B, 1.5MB with N-ISDN
It is possible to transfer digital data up to about / sec to the user, and it is possible to transfer information such as telephone, facsimile, still images and video conferences.

However, in recent years, there has been a demand for video information such as CATV, high quality video transmission, and large-capacity file transfer. The system to deal with this is BI
SDN (broadband ISDN), which enables large-capacity digital data transfer.

An ATM switch is used in the B-ISDN. The packet multiplex method in packet switching is most often used as the asynchronous multiplex communication method, and the HDLC procedure is used as the procedure. By these procedures, flow control is performed and transmission error is reduced to 0.
I am trying.

However, this method has a drawback that complicated processing is required and high speed is difficult. Therefore, in the ATM system, the processing is simplified, the early detection / retransmission procedure is not used, and the length of the ATM cell (packet) is made constant.

As shown in FIG. 7, the basic structure of the ATM is that the terminals 10 and 11 which are workstations are connected via terminal adapters (TA) 12 and 13, respectively, to the ATM switch 1.
It is connected to 4, 15. And ATM switch 14,1
5 is connected to the network 16.

When communication is started, for example, the terminal 10 uses the network 1
Logical channel numbers are assigned from 6. After calling the partner terminal 11, the network 16 determines a path passing through the line and notifies the passing ATM node. This ATM node (ATM node represents a plurality of communication nodes provided in the network 16) determines the logical channel number of the path used for communication according to the instruction and registers the conversion method of the logical channel number in the routing table. To do.

The terminals 10 and 11 attach the assigned logical channel number to the header of the cell and send it to the network. As a result, each node converts the logical channel number of the cell into the logical channel number of the next path according to the routing table and sends it out, and delivers the cell to the partner terminal 11.

In this data transfer, LAP-B is used as shown in FIG. This LAP-B is CCI
TT Recommendation X. The procedure is based on 25, and each terminal is connected by the LAP-B via the exchange (SWITCH) 17.

The cell structure used in the so-called ATM connected by the LAP-B has the structure shown in FIG. One cell has 53 bytes, and 50 bytes are used as an ATM header. In FIG. 9, flow control (GFC) is first provided. When a plurality of terminals are connected to the user interface and the buffer memory interface cable or the like is shared, flow control becomes necessary. It is provided for this purpose. Then VPI (VIR
(TUAL PATH IDENTIFYE) is provided. In ATM, some logical channels are combined into V
IRTURALPATH is created and used as a management unit of the network. VPI is an identifier showing this VIRTUALPAT.

Further, in ATM, a plurality of logical channels can be used by using a logical channel number. V
CI is an identifier of this logical channel. PT (PA
YLOAD TYPE) indicates that the cell is for network management. HEC (HEADER ERROR
CONTROL) is a code for error correction in the header part. The ATM cell has a SAR header behind the ATM header, and further has a data and SAR trailer behind it.

ATM is divided into three layers: a physical layer, an ATM layer, and an adaptation layer. The physical layer functions as the physical medium itself and bit synchronization. A
The TM layer has functions such as cell synchronization cell and cell multiplexing.
The adaptation layer has a role of an interface of the user information and the ATM system, and disassembles the user information cell,
Take measures against assembly, loss of cells, etc.

FIG. 10 is a sequence diagram of data transfer control. When a SETUP REQ is generated from the terminal 10, the terminal adapter section (TA) 12 sends out a SETUP (VPI / VCI request) to the network 16 via the ATM 14. On the other hand, the network 16 similarly sends the request to the TA 13 via the ATM 15, and the signaling processing unit of the TA 13 sends INCOMING CALL INDICATIO.
N is sent to the terminal 11.

The terminal 11 is INCOMING CALL
ACCEPTANCE is transmitted to TA 13, and TA 13 sends CONN to the network 16. Prior to this, when the network 16 received the SET UP, the CALL-PROC (VP
I / VCI) to the TA 12. Then, the above-mentioned CONN is added from the network 16 to the signal processing unit of the TA 12, and the network further sends CONN-ACK to the TA 13 side.

On the other hand, the LAPB sequence operates as follows. When the VPI / VCI notification is added to the data transfer control unit of the TA 12 from the terminal 11 side and the link processing request (VPI / VCI, DT) is transmitted by the signaling processing unit of the TA 12, the data transfer control unit sends the LAP-B setting request to the ATM. To send to. The request is sent to the TA 13 on the receiving side via the network 16 by SABM (SADM: SET ASYMCHRONO).
Received as US BALANCED MODE).

The network 16 corresponds to the non-numbering verification (U
A: UNNUMBERED ACKNOWLEDGE), and then LAP-
A B-link establishment notification is sent to TAs 12 and 13, and TA1
The data transfer control units 2 and 13 notify the signaling processing unit of the link establishment, and the SETUP COMPLETE
To the terminal 10 and the terminal 11, respectively. As a result, the LAP-B link is established (layer), and X.
The layer 3 communication is controlled by the 25 protocol. Then the data is transferred.

When the communication is terminated, the terminal 10 issues a DISC REQUEST, the TA 12 changes the link release request, and further the LAP-B link release request, joins the ATM, and the ATM issues the DISC. Then, the release completion corresponding to this becomes the LAP-B link release completion and is notified to both signaling processing units.

By this reception, the signaling processing unit of the TA 12 notifies the signaling processing unit of the TA 13 side via the network 16. Correspondingly, REL is transferred from the network to the corresponding signaling processing unit,
From the signaling processing unit to the terminal 10, the DISC C
OMPLETE, and REL-CO for network 16
Notify M. Similarly, REL is sent from the signaling processing unit, REL-COM is similarly transferred from the network 16, and DISC INDICATION is output to the terminal 11. And from terminal 11 DISC RESPON
The SE is output to the signaling processing unit and the link is released.

Communication is established and released by setting the connection of LAP-B as described above.

[0021]

The terminals 10 and 11 are connected by LAP-B as shown in FIG. On the other hand, when multiplexing LAP-B, LAP-B
Since only one link can be set on the physical line, the multiplexing on one LAP-B is performed by the control of the upper layer. However, in addition to LAP-B multiplexing and one-to-one communication, simultaneous LAP-B for one-to-many terminals is possible.
It had a problem that it could not be set.

The present invention is based on the LAP-B in B-ISDN.
It is an object of the present invention to provide a LAP-B multiplexing method for setting a plurality of links.

[0023]

The present invention relates to a terminal adapter for setting a LAP-B link provided between a network and a terminal.

Communication identifier management means for managing a communication identifier to which a plurality of links are assigned is provided for one terminal, and 1
LAP from one terminal to multiple terminals
Manage the B link.

With this management means, LA with one terminal is
Multiple links of P-B can be managed, and multiple connections of LAP-B are possible.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings.
FIG. 1 is an explanatory diagram of multiplexing in LAP-B in B-ISDN. The source terminal 20 physically establishes a virtual virtual communication channel to the B-ISDN by the LAP-B link to the destination terminals 21 and 22 via the physical line 23. A communication identifier management unit 19 is provided on the terminal adapter side in order to allocate a plurality of links to one terminal, and the communication identifier management unit 19 manages the state of each link.

FIG. 2 is a block diagram of the terminal adapter 24 provided between the terminal and the network. The terminal adapter (TA) 24 is provided with a terminal communication control unit 25 that controls communication with a terminal, a LAP-B control unit 26 that establishes a LAP-B link, and a B-ISDN communication identifier management unit 27. This B-ISDN communication identifier management unit 27 manages the LAP-B link of each ISDN communication corresponding to the communication destination terminal.

FIG. 3 is a hierarchical structure diagram of links. The driver unit is provided with a terminal driver, a terminal driver for the network 23, and a network driver, respectively. There is a control layer in the upper layer thereof, and in this control layer, transfer control is provided for the terminal driver, and a B-ISDN communication identifier management unit is provided for the network driver. This B-ISDN communication identifier management unit performs LAP-B communication control for controlling LAP-B and LAP-D communication, and LAP-D.
The network driver is controlled by the instruction from the communication control.
Further, a transfer terminal control unit is provided in the application layer corresponding to the LAP-B communication control and the transfer control, and the transfer between the terminals via the network by the data transfer control application is performed by this application layer.

FIG. 4 is a sequence diagram of LAP-B multiplexing. When a communication channel acquisition request is issued from the terminal TE, TA2
The terminal communication control unit 25 of No. 4 issues a channel acquisition request to the network 23, and the network 23 sends a communication channel acquisition notification of the receiving side to TA2.
It is sent to the terminal communication control unit 25 'of 4'. The network 23 also returns an acquisition notice for the request to the TA 24,
The destination TA 24 recognizes the passage notification from the LAP-B control unit 26 '. Then, from the terminal communication control unit 25 to the LAP
When a setting request is added to the -B control unit 26, the LAP-B control unit 26 issues a SABM to the network 23 and the transmission destination TA2
At 4 ', UA is returned. Further, the terminal communication control unit 25 '
To the terminal communication control unit 2
5'transmits completion of communication channel acquisition to the terminal 20. In addition, a notification of link establishment is also sent to the communication terminal control unit 25 of the transmitting side TA 24, and the terminal communication control unit 25 ′ notifies the terminal 20 ′ of completion of communication channel acquisition. As a result, the link in LAP-B is established and communication is in progress.

On the other hand, when the same request is further generated,
By obtaining a similar procedure for a similar communication path acquisition request, another link can be established as shown in FIG.
In this case, the communication identifier management unit 27 manages LA
LO corresponding data of management information, L1 corresponding data ... Are provided for the P-B link identifiers L0, L1 ,. The corresponding data is the identifier information part and the VPI.
Also, it is managed by VCI as shown in FIG.

By the respective management as described above, the X.
A plurality of LAP-B used in No. 25 can also be used in B-ISDN. In addition, communication is multiplexed by acquiring a plurality of virtual communication paths at the physical level of ISDN. Therefore, the LAP-B link can be set for each of several virtual communication paths acquired on the physical line, and the LAP-B can be multiplexed.

That is, the above operations are summarized as follows. When the terminal sends a communication path acquisition request to the TA to acquire a communication path in the physical line, the TA control unit sends a communication path acquisition request to the network. The network acquires the communication path and notifies the originating and terminating TAs of its identifier. TA
The control unit sets the LAP-B link on this communication path by the procedure described above. After this setting, communication is possible. When the TA again receives a request for acquisition of a new communication path from the TE side, the network acquires the communication path by the same procedure. Then, another LAP-B link is set on this communication path, and communication is simultaneously performed by a plurality of LAP-B. The TA has a B-ISDN communication identifier management unit for managing a physical level communication path and a LAP-B control unit communication control unit, and all data processed inside the TA has a B-ISDN communication identifier. Communication is performed based on the above and the destination of data is correctly determined.

[0033]

According to the conventional method X. LAP used in 25 only-
The B link level protocol can also be used in B-ISDN, and more than one LAP-B on the physical line.
It is possible to provide LAP-B multiplexing by providing a physical virtual communication path. In addition, the identifiers of the respective communication paths are managed by the B-ISDN communication identifier management unit inside the TA, and it is possible to determine the destination of data transmission / reception. -B can be set.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of multiplexing of LAP-B in B-ISDN.

FIG. 2 is a configuration diagram of a terminal adapter.

FIG. 3 is a block diagram of hierarchical management.

FIG. 4 is a sequence diagram of LAP-B multiplexing.

FIG. 5 is an explanatory diagram of multiplexing of LAP-B.

FIG. 6 is a configuration diagram of management information.

FIG. 7 is a system configuration diagram of an ATM switching network.

FIG. 8 is an explanatory diagram of LAP-B.

FIG. 9 is a configuration diagram of a header.

FIG. 10 is a sequence diagram.

FIG. 11 is an explanatory diagram of a conventional LAP-B.

Claims (1)

[Claims] 1. A terminal adapter which is provided between a network and a terminal and which sets a LAP-B link, is provided with communication identifier management means for managing a communication identifier in which a plurality of links are assigned to one terminal. LAP-B characterized by
Multiplexing method.