JPH0498918A - Digital multiplexing circuit - Google Patents

Abstract

PURPOSE:To attain efficient connection to a time division multiplexer by using the time slots of a prescribed number assigned to every path for the information subjected to label multiplexing. CONSTITUTION:A label read time slot allocation section 19 receiving a fixed length packet from a digital private line 17 reads the label information and identifies an incoming terminal equipment to send a fixed length packet to a terminal interface section (I/F) 15. The I/F 15 converts a received fixed length packet into a relevant variable length packet and sends it to each packet form terminal equipment 11 or to each non-packet form terminal equipment 13 while the packet is restored into a bit string. When all information from plural terminal equipments is subjected to label multiplexing, a time slot is allocated to each path on the line 17. Thus, while the line utilizing efficiency by label multiplexing is enhanced, the time slot location is used as path information and efficient connection to a time division multiplexer is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a digital multiplexing method that combines a time position multiplexing method and a label multiplexing method in digital communication.

[Conventional technology]

Conventional multiplexing methods in digital communications are broadly classified into two types: time position multiplexing and label multiplexing.

The time position multiplexing method is a method of multiplexing information by assigning information from each terminal to time slots within a frame, and route (destination) information is identified by the time position of the time slot.

This time position multiplexing method is usually used by a time division multiplexer (
It is used in the form of connecting a large number of low-speed terminals to a high-speed digital dedicated line via TDM).

On the other hand, the label multiplexing method is a method in which information from a terminal is divided into predetermined blocks, a label is added to the beginning of each block, and multiplexed. Route information is identified by the label in the header. Note that ATM (asynchronous transfer mode) uses cell multiplexing using fixed-length cells, and DD
X and other data exchange networks employ packet multiplexing using variable length data exchange packets.

This label multiplexing method converts only meaningful information from terminals into cells or packets and dynamically allocates them to vacant time slots on the line, making it possible to flexibly respond to changes in the amount of information. .

FIG. 3 is a diagram showing how multiplexing is performed using the time position multiplexing method and the label multiplexing method.

FIG. 3(a) shows the case of the time position multiplexing method, where thick lines indicate frame boundaries and dotted lines indicate term boundaries for each direction of time slots corresponding to paths α, β, and γ.

In the time position multiplexing method, information A, B, C from each terminal is
2... are respectively assigned to predetermined time slots.

FIG. 3(b) shows the case of the label multiplexing method, in which cells composed of a header indicating route information and an information field are multiplexed in a non-fixed manner.

In high-speed communications, label multiplexing, especially packet multiplexing, is considered unsuitable because it takes time to process headers, and time position multiplexing, which allows for high-speed processing, has been the norm. With the development of communication control LSIs that perform high-speed protocol processing and the development of ATM cell multiplexing systems that can handle high-speed processing, label multiplexing systems in the high-speed area have also reached a practical level.

[Problem B to be Solved by the Invention] In the label multiplexing method, the route indicated in the cell or packet header and the position of the multiplexed time slot are random.

On the other hand, in the time position multiplexing method, a fixed time slot is assigned to each terminal from the start to the end of communication, so even if the amount of information decreases and a time slot becomes unused, other Could not be assigned to terminal communication. Therefore, compared to the label multiplexing method, which can flexibly respond to changes in the amount of information, the line usage efficiency has been lower.

In this way, the label multiplexing method and the time position multiplexing method are fundamentally different in how they handle route information.

Therefore, when connecting a label multiplexing device such as a packet multiplexing system (PMX) to an existing communication network using a time division multiplexing device (TDM), for example, a dedicated TDM for each label route is required. The configuration was such that each device was housed in a separate dedicated digital line, making it difficult to implement it efficiently.

The present invention combines the existing time position multiplexing method, which allows efficient use of a single high-speed digital dedicated line, with the label multiplexing method, which has high line usage efficiency, to create a digital multiplexing system that combines the advantages of both. The purpose is to provide a method.

[Means to solve the problem]

The present invention is a digital multiplexing method that performs time position multiplexing by allocating input information to time slots assigned corresponding to information routes, in which the route of input information is identified, and a predetermined number of time slots corresponding to each route are assigned. The information is label-multiplexed by assigning the time position of the information in a non-fixed manner during the time slot.

[For production]

In the conventional time position multiplexing method, the time position allocation of information to each time slot within a frame is fixed, but since a predetermined number of time slots are allocated for each route, the present invention Label multiplexing is performed for information on the same route for slots.

Note that the present invention differs from conventional label multiplexing methods in that when label multiplexing is performed, time slots are allocated for each information route. Furthermore, this method differs from the conventional time position multiplexing method in that the time position of the label multiplexed information is non-fixedly assigned to a predetermined number of time slots allocated to the same route.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

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

In the figure, a multiplexer 1o according to the invention includes a packet type terminal (PT) 11 and a non-packet type terminal (NP
T) 13 terminal interface units (T
IF) 15 and a label reading/time slot allocation section 19 that accommodates a digital dedicated line 17.

Note that each packet format terminal 11 sends out information as a variable length packet, and each output packet is assigned A (AI, A
2, A3,...), B(Bl, B2, B3, B4,...
), C(C1, C2, C3,...). On the other hand, each non-packet type terminal 13 sends out information as a bit string, and each bit string is designated as E and F.

Each terminal interface unit 15 converts or assembles the packet or bit string received from each terminal into a fixed-length packet and sends it to the label reading/time slot allocation unit 19. That is, variable length buckets) AI, A2, A3 are fixed length packets al
, a2, B3, B4, B5, and B6. The same applies to variable length packets B and C. Furthermore, the bit strings are assembled into fixed length packets d1 and B2 with labels attached. The same applies to the focus rows E and F. Note that the data indicated by double frames in the figure is packet type, and -
The data shown in the form is non-packet type.

Therefore, each terminal interface section 15 functions as a packet assembly/disassembly section, and the multiplexer 10 unifies the interface of the information received from each terminal at this stage, and performs label multiplexing.

The label reading/time slot allocation section 19 reads the label information of the fixed length packet received from each terminal interface section 15, and identifies the route from the routing information. Furthermore, label reading/time slot allocation section 1
9 sends each fixed-length packet to the digital dedicated line 17 based on the identified route, and at this time allocates it to an empty time slot of each time slot in the frame assigned to each route. That is, in each time slot corresponding to route α, fixed length packets al~
fixed length packets b1 to b4, d1 are allocated to each time slot corresponding to route β.
~d2 are allocated, and fixed length packets c1 to c3 and el-C3 are allocated to each time slot corresponding to route γ.

Next, the reception operation will be explained.

The label reading/time slot allocation unit 19 that receives the fixed-length packet from the digital dedicated line 17 reads the label information, identifies the destination terminal from the routing information, and sends the fixed-length packet to the terminal interface unit 15 that accommodates the destination terminal. Send fixed length packets.

Here, the terminal interface unit 15 accommodating the packet-format terminals 11 converts the received fixed-length packets into corresponding variable-length packets and sends them to each packet-format terminal 1.
Send to 1. Further, the terminal interface unit 15 accommodating the non-packet type terminals 13 disassembles the received fixed length packet, returns it to a bit string, and sends it to each non-packet type terminal 13.

In this way, when label multiplexing all information from a plurality of terminals, time slots are allocated for each route on the digital dedicated line 17. Note that within multiple time slots assigned to the same route, fixed assignments are not made to individual time slots, but non-fixed assignments are made in the same way as in the label multiplexing method, in order to accommodate fluctuations in the amount of information. It has become.

Therefore, the time slot position can be used as route information while increasing line usage efficiency through label multiplexing, and efficient connection to a time division multiplexer (TDM) can be made possible.

FIG. 2 is a block diagram showing an example of the configuration of a communication network using a multiplexing device according to the present invention.

In the figure, it is assumed that a time division multiplexer (TDM) 21 is connected by a digital dedicated line 17, and a communication network based on the time position multiplexing method is constructed.

On the other hand, the packet type terminal 11 and the non-packet type terminal 13 are accommodated in a local area network (LAN) 23.

Here, when the time division multiplexing device 21 and the local area network 23 are connected via the multiplexing device IO corresponding to the label multiplexing method and the time position multiplexing method according to the present invention, the time division multiplexing method is performed as described above. Even though the information is label-multiplexed, the communication device 21 allocates time slots for each route, making it possible to identify routes. Can be accommodated well.

〔Effect of the invention〕

As explained above, the present invention uses a predetermined number of time slots assigned to each route with label multiplexed information, thereby increasing the line usage efficiency through label multiplexing and changing the time slot position to the route information. It can be used as

Therefore, efficient connection to a time division multiplexer (TDM) is possible, and multi-way communication that takes advantage of the label multiplexing method can be realized using a single digital dedicated line.

Particularly, for example, when a private company network has already been constructed using a time division multiplexer and a digital dedicated line, the use of the multiplexer according to the present invention makes it easy to efficiently connect terminals to that communication network. become.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a block diagram showing an example of the configuration of a communication network using a multiplexing device according to the present invention. FIG. 3 is a diagram showing how multiplexing is performed using a time position multiplexing method and a label multiplexing method. 10...Multiplexing device, 11...Packet format terminal (
PT), 13...Non-packet type terminal (NPT), 1
5...Terminal interface unit (TIF), 17...
Digital dedicated line, 19... Label reading/time slot allocation unit, 21... Time division multiplexing device (TDM)
, 23...Local area network (LAN). Patent applicant Nippon Telegraph and Telephone Corporation

Claims (1)

[Claims] (1) In the time slot assigned to correspond to the information route,
In a digital multiplexing method that performs time position multiplexing by assigning each input information, the route of the input information is identified, and the time position of the information is non-fixedly assigned to a predetermined number of time slots corresponding to each route. A digital multiplexing method characterized by label multiplexing.