JPH06261057A - Line concentrator for local area network - Google Patents

Abstract

PURPOSE:To easily realize closed area connection limited to packet transfer only within the same group even when the same line concentrator is used for plural groups. CONSTITUTION:Group identification header additional functions 12, 22 and group filtering functions 13, 23 are provided in subscriber circuits 11, 21 of a line concentrator 1. Group identification header additional functions 12, 22 add group identification information preset to registers 14, 24 as a group identification header to a packet received from subscriber terminal equipments 2, 3 and transfer the result onto a trunk bus 4. When the group identification header of a packet transferred on the trunk bus 4 is coincident with group identification information of the registers 14, 24 and the destination address of said packet is coincident with the address of the subscriber terminal equipments 2, 3, the group filtering function 13, 23 eliminate the group identification header from the packet and send the result to the subscriber terminal equipments 2, 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concentrator of a local area network, and more particularly to a closed area connection method in a concentrator of a star type local area network.

[0002]

2. Description of the Related Art Conventionally, in a star type local area network concentrator, a simultaneous broadcast type backbone bus,
And a subscriber circuit accommodating a subscriber terminal. The subscriber circuit of this concentrator is provided with a bus transmission interface for transferring a packet received from the accommodated subscriber terminal to the backbone bus.

Also, when it is detected that the destination address of the packet transferred on the backbone bus and the address of the subscriber terminal to be accommodated are detected in the subscriber circuit of the concentrator, the packet is taken in, An address filtering function for transmitting to a subscriber terminal accommodating the is provided.

[0004]

In the above-described conventional star-type local area network concentrator, the destination address of the packet transferred on the backbone bus is accommodated in its own circuit by the address filtering function of the subscriber circuit. If it matches the address of the subscriber terminal, the packet is taken in regardless of the sender subscriber terminal and the packet is transmitted to the subscriber terminal accommodated in its own circuit. For this reason, when the same concentrator is used in a plurality of groups, it is difficult to establish a closed connection that limits packet transfer only within the same group.

Therefore, an object of the present invention is to solve the above problems and to easily realize a closed connection in which only the packet forwarding within the same group is limited even when the same concentrator is used in a plurality of groups. It is to provide a concentrator for a local area network.

[0006]

A local area network concentrator according to the present invention is a local area network concentrator comprising a plurality of subscriber circuits each accommodating a corresponding subscriber terminal, and is preset. Holding means for holding group identification information of the subscriber terminal,
A means for adding the group identification information to the packet received from the subscriber terminal and transferring the packet to the backbone bus, and a group identification information added to the packet transferred on the backbone bus are held in the holding means. A means for determining whether or not the destination address that matches the group identification information and that is added to the packet matches the address of the subscriber terminal, and a match between the group identification information and the destination address is detected. Each of the plurality of subscriber circuits is provided with means for transmitting data other than the group identification information among the packet data from the backbone bus to the subscriber terminal.

[0007]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In the figure, a concentrator 1 has subscriber circuits 11 and 21 for accommodating subscriber terminals 2 and 3, respectively, and a backbone bus 4. Each of the subscriber circuits 11 and 21 is provided with a group identification header adding function 12 and 22 and a group filtering function 13 and 23.

The group identification header adding functions 12 and 22 add the group identification information preset in the registers 14 and 24 to the packet received from the subscriber terminals 2 and 3 via the concentrator branching units 15 and 25. And is transferred to the trunk bus 4 via the branching branch units 16 and 26.

Here, group identification information indicating a group to which the subscriber terminals 2 and 3 belong is preset in the registers 14 and 24. The group identification information can be set in the registers 14 and 24 from the subscriber terminals 2 and 3,
It is also possible to set from the outside through an input device (not shown).

In the group filtering functions 13 and 23, the group identification header of the packet transferred on the backbone bus 4 matches the group identification information of the registers 14 and 24, and the destination address of the packet is the subscriber terminal 2 or 2.
It is determined whether or not it matches the address of No. 3.

As a result, the group filtering function 1
When it is determined that the group identification header and the destination address of the packet match, the packets 3 and 23 take in the packet through the concentrator / branching units 16 and 26 and delete the group identification header from the packet. The group filtering functions 13 and 23 collect the received packets by the line concentrators 15 and 2
5 to the subscriber terminals 2 and 3.

The subscriber terminals 2 and 3 are terminals connected to an existing local area network, and the backbone bus 4
Is a simultaneous broadcast type bus. Further, P in the drawing is a packet, P1 is a destination address (DA), and P2 is a group identification header (GRP).

The operation of one embodiment of the present invention will be described with reference to FIG. The operation of transmitting a packet in which the address of the subscriber terminal 3 is set as the destination address from the subscriber terminal 2 will be described below.

When the subscriber terminal 2 transfers data to the subscriber terminal 3, the subscriber terminal 2 transmits to the concentrator 1 the packet P in which the address of the subscriber terminal 3 is set as the destination address P1. Upon receiving the packet P from the subscriber terminal 2, the subscriber circuit 11 of the concentrator 1 adds the group identification header P2 to the packet P based on the group identification information of the register 14 by the group identification header adding function 12 to form a backbone bus. Transfer to 4 above.

At this time, if the subscriber terminals 2 and 3 belong to the same group, the group filtering function 23 of the subscriber circuit 21 of the concentrator 1 stores the group identification header P2 of the packet P on the backbone bus 4 in the register 24. It is determined that it matches the group identification information of.

At the same time, the group filtering function 23
Determines that the destination address P1 of the packet P on the backbone bus 4 matches the address of the subscriber terminal 3. As a result, the group filtering function 23 takes in the packet P from the backbone bus 4 and outputs the group identification header P2.
Is deleted and the packet P is transferred to the subscriber terminal 3.

On the other hand, if the subscriber terminals 2 and 3 belong to different groups, the group filtering function 23 of the subscriber circuit 21 of the concentrator 1 uses the packet P on the backbone bus 4.
It is determined that the group identification header P2 of No. 2 does not match the group identification information of the register 24.

Therefore, even if the destination address P1 of the packet P on the backbone bus 4 matches the address of the subscriber terminal 3, the group filtering function 23 does not fetch the packet P from the backbone bus 4, The packet P is not transferred to the subscriber terminal 3.

Thus, the subscriber circuit 1 of the concentrator 1
1 and 21, group identification header addition functions 12 and 22 for adding the group identification header P1 to the packet P received from the subscriber terminals 2 and 3 and transferring it to the backbone bus 4, and the packet P on the backbone bus 4. When the group identification header P2 indicates the group to which the subscriber terminals 2 and 3 belong and the destination address P1 indicates the address of the subscriber terminals 2 and 3, the packet P is fetched from the backbone bus 4 to identify the group. Group filtering functions 13 and 2 for deleting the header P2 and transferring the packet P to the subscriber terminals 2 and 3.
By including 3 and 3, a closed connection can be realized using a terminal connected to an existing local area network.

As a result, the subscriber terminals 2 and 3 receive only the data of the same group, and the transfer of the data beyond the group is restricted. Therefore, even when the same concentrator 1 is used in a plurality of groups, it is possible to easily realize a closed connection that is limited to packet transfer only in the same group.

[0022]

As described above, according to the present invention, the function of adding the group identification information of the subscriber terminal to the packet received from the subscriber terminal and transferring the packet to the backbone bus, and the function of transferring the packet on the backbone bus have been used. Of the packet from the backbone bus when it is detected that the group identification information added to the packet matches the group identification information of the accommodated subscriber terminal and the destination address matches the address of the subscriber terminal. By providing each of a plurality of subscriber circuits with a function of transmitting data other than group identification information among the subscriber terminals, packet transfer within the same group even when the same concentrator is used in a plurality of groups There is an effect that it is possible to easily realize the closed area connection limited to.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

[Explanation of symbols]

 1 line concentrator 2,3 subscriber terminal 4 backbone bus 11,21 subscriber circuit 12,22 group identification header addition function 13,23 group filtering function 14,24 register P packet P1 destination address P2 group identification header

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 8732-5K H04L 11/20 103 E

Claims (1)

[Claims] 1. A concentrator of a local area network comprising a plurality of subscriber circuits each accommodating a corresponding subscriber terminal, and holding means for holding preset group identification information of the subscriber terminal. A means for adding the group identification information to the packet received from the subscriber terminal and transferring the packet to the backbone bus, and a group identification information added to the packet transferred on the backbone bus are held in the holding means. A means for determining whether or not the destination address that matches the group identification information and that is added to the packet matches the address of the subscriber terminal, and a match between the group identification information and the destination address is detected. And a means for transmitting data other than the group identification information in the packet data from the backbone bus to the subscriber terminal. A concentrator which is included in each of a plurality of subscriber circuits.