KR20020004554A - Method for providing low speed data service in access network apparatus - Google Patents

Abstract

PURPOSE: A method for providing slow data service in an access network unit is provided to present a data multiplexing method to implement ITU(International Telecommunication Union) X.50 for an access network unit. CONSTITUTION: A frame, divided by a frame synchronous signal(Fsync), is composed of 32 channels of 64Kbps. Among the 32 channels, channels 0 and 16 are for control, and the others for data. The 64Kbps data channels comprises a plurality of sub channels respectively so as to accept a plurality of low-speed subscribers. In case that slow subscriber data has a bit rate of 600bps, the maximum number of acceptable subscribers is 80 as each 64Kbps data channel contains 80 sub channels. In case that slow subscriber data are 2400bps, the maximum number of acceptable subscribers is 80 as each 64Kbps data channel contains 20 sub channels. For 4800bps slow subscriber data, the maximum number of acceptable subscribers is 10 as each 64Kbps data channel contains 10 sub channels. For 9600bps slow subscriber data, the maximum number of acceptable subscribers is 5 as each 64Kbps data channel contains 5 sub channels.

Description

METHOD FOR PROVIDING LOW SPEED DATA SERVICE IN ACCESS NETWORK APPARATUS}

The present invention relates to a network device, and more particularly, to a method for providing a low speed data service in an access network device that is a subscriber matching device.

The main communication service is telephone, and the current network is designed and developed from the telephone network. In recent years, however, high-speed interchange services such as ISDN and leased lines, and broadband video services such as video telephony, video on demand (VOD), and cable television (CATV) are already commercialized or are expected to be commercialized. In addition, as computers become more popular in every household, the frequency of use of communication networks is increasing, and as a result, the demand for transmission capacity applied to communication networks is increasing day by day. In order to cope with this environment, optical communication technology that enables high-speed transmission has been applied to the elements of communication networks. Up to now, it has been mainly applied between out-of-city stations and is used for high-speed transmission between nodes of a transmission network. In recent years, the construction of optical subscriber network has begun to be applied to some subscriber segments.

Typically, the network consists of a backborn network including a PSTN, an ATM network, a PSDN, a dedicated line, and a subscriber network. The subscriber network is largely composed of an access network, which is a network that connects from a terminal switching center of a telephone station to a subscriber premises, and a customer premise network, which is an internal communication network of the subscriber. In general, the subscriber network means an access network.

In this network configuration, an access network device, which is a subscriber matching device, serves to match a link connection between subscribers having various data rates and switch devices of a transmission system. Therefore, the link on the subscriber side is multiplexed through the access network device and connected to the link of the switch device.

On the other hand, International Telecommunication Union (ITU) X.50 proposes a standard for multiplexing low-speed data. Low speed data subscribers below 64 Kbps can use a single 64Kbps channel alone, and multiple low speed data subscribers can use a single 64Kbps channel together. Like the latter, multiplexing techniques must be performed to allow multiple subscribers to use a single 64Kbps channel.

Accordingly, an object of the present invention is to provide a data multiplexing method for implementing the X.50 standard proposed by the ITU to an access network device that is a subscriber matching device.

Another object of the present invention is to provide a method of multiplexing subscriber data so that a low-speed data subscriber can use a 64 Kbps channel for data call service when a subscriber card supporting X.50 is mounted in an access network device. It is.

1 is a diagram illustrating a basic structure in which multiple low-speed subscriber data are multiplexed on each of 64 Kbps channels according to an embodiment of the present invention.

2 is an exemplary diagram of a configuration of multiplexing a plurality of low-speed subscriber data into one data channel according to an embodiment of the present invention;

FIG. 3 is a diagram illustrating a correlation between key tasks and procedures included in the common control unit (CCU) of FIG. 2 and configured for low-speed subscriber data multiplexing; FIG.

4 is a flowchart for selecting a subscriber highway;

5 is a flowchart for releasing a subscriber highway;

6 is a subscriber time slot setup flow chart (port activation),

7 is a subscriber timeslot setup flow chart (port deactivation),

8 is a flowchart for switching subscribers to multiplexed channels and links / channels;

9A and 9B illustrate a structure of a highway, timeslot, and subtimeslot management buffer for subscriber multiplexing;

10 is a view showing a grouping ID management buffer structure according to an embodiment of the present invention;

11 illustrates a link multiplexing management buffer structure according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the same elements in the figures are represented by the same numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

The basic idea of the present invention is to accommodate a plurality of low speed subscriber data in one data channel. 1 illustrates a basic structure in which a plurality of low-speed subscriber data are multiplexed on each of 64 Kbps channels according to an embodiment of the present invention. In FIG. 1, an E1-class signal (2048 Kbps) is used as an example. The frame distinguished by the frame sync signal Fsync consists of 32 channels with a transmission rate of 64 Kbps. Of the 32 channels CH0 to CH31 in the frame, channels 0 (CH0) and 16 (CH16) are for control and the remaining channels are for data.

In the present invention, each of the channels for 64 Kbps data constitutes a plurality of subchannels to accommodate a plurality of low speed subscribers. The number of subchannels is equal to the maximum number of subscribers that can be serviced. In the case of low-speed subscriber data with a transmission rate of 600bps, the 64Kbps data channel accommodates 80 subchannels, so the maximum number of subscribers that can be serviced is 80. In the case of low-speed subscriber data at 2400 bps, the 64Kbps data channel accommodates 20 subchannels, so the maximum number of subscribers that can be serviced is 20. In the case of low-speed subscriber data with a transmission rate of 4800bps, the channel for 64Kbps data accommodates 10 subchannels, so the maximum number of subscribers that can be serviced is 10. In the case of low-speed subscriber data with a transmission rate of 9600bps, the 64Kbps data channel accommodates five subchannels, so the maximum number of subscribers that can be serviced is five.

As described above, in order to configure each of the channels for 64 Kbps data into a plurality of subchannels, low-speed subscriber data must be multiplexed.

2 illustrates an example of multiplexing a plurality of low-speed subscriber data into one data channel according to an embodiment of the present invention.

10 is a plurality of low speed subscribers, for example, 600 bps, 2400 bps, 4800 bps, 9600 bps, etc., as mentioned in FIG. 1. The plurality of low speed subscribers may be implemented as a low speed data unit (LSDU) card as a subscriber card mounted in an access network device to support X.50. The multiplexer 12 multiplexes a plurality of low-speed subscriber data provided from the plurality of low-speed subscribers 10 into one channel for data. The multiplexed data is switched in the switch unit 16 through the user highway 14 and then output on the network through the link highway 18. The Common Control Unit (CCU) 20 controls each part of the access network as a control unit of the access network.

3 illustrates a correlation between main tasks and procedures included in the CCU 20 of FIG. 2 and configured for low-speed subscriber data multiplexing according to an embodiment of the present invention. In FIG. 3, two tasks (man machine interface) task 22 and switching task 24 and four procedures, that is, a subscriber management program, are configured as a configuration for low-speed subscriber data multiplexing. There is a procedure 26, a link management procedure 28, a switching procedure 30, and a hardware control procedure 32.

Among the two tasks, the MMI interface task 22 acts as a window that accepts a provision for the type of service the network operator wishes to provide as a queue or semaphore. If provisioning is for a subscriber, go to subscriber management procedure 26, follow the subscriber port multiplexing procedure, and control the subscriber card, eg, LSDU cards. If provisioning is for the link, then link management procedures 28 allow link and channel management. Among the two tasks, the switching task 24 calls the switching procedure 30 to make the actual call connection and the link card (the link card includes the switch section 16 and the link highway 18 in FIG. 2). ) To monitor. The switching task 24 is a periodic task that operates several hundred milliseconds, preferably 500 msec. The switching procedure 30 may be used by both the MMI interface task 22 and the switching task 24, and is provided with a function for eliminating the collision caused by the use of both. That is, when the MMI interface task 22 requests the call of the switching procedure 30, only the flag is set, and the switching task 24 drives the actual call. If the flag is set, the MMI interface task 22 is called.

The LSDU card, which is a subscriber card, has four types of data transmission speeds, such as 600bps, 2400bps, 4800bps, and 9600bps, as described above. According to the X.50 specification, the number of subscribers multiplexed by these transmission rates is specified as follows.

600 bps (80 subscribers), 2400 bps (20 subscribers), 4800 bps (10 subscribers), 9600 bps (5 subscribers)

According to an embodiment of the present invention, the LSDU card provision for multiplexing a plurality of low-speed subscriber data into each of a plurality of channels basically constitutes the following items.

1.Port Status (Active / Inactive)

2. Sub time slot, group, baud rate

3. Baud rate

4. character length

5. Synchronization method (synchronous / asynchronous): The characteristic length value is meaningless during synchronization.

6. Link / channel to connect per port

Items 3 to 5 in the above provision need to be recorded only once in hardware as data for operating in hardware, and items 1 and 2 and 6 for multiplexing low speed subscriber data according to an embodiment of the present invention. Important consideration should be given.

According to an exemplary embodiment of the present invention, buffers having a structure as shown in FIGS. 9A and 11B are provided to multiplex a plurality of low-speed subscriber data in one channel.

9A and 9 illustrate a structure of a highway, timeslot and subtimeslot management buffer for subscriber multiplexing. 9A and 9B, the variable X is the maximum number of highways supported by the system to the subscriber card, Y is the maximum number of slots of the subscriber card, and Z is the maximum number of usable subtimeslots. The information elements below occupy one byte each.

In the following, the buffer structure of FIG. 9A is written in, for example, C language of a computer program language (the structure part is omitted), and a function thereof is described.

userHighway [X] .userType;

userHighway [X] .useSlot [Y];

userHighway [X] .timeSlot [32] .mastSlot;

userHighway [X] .timeSlot [32] .mastPort;

userHighway [X] .timeSlot [32] .timeSlot [Z] .slot;

userHighway [X] .timeSlot [32] .timeSlot [Z] .port;

Where userHighway [X] .userType; Is the subscriber card type set in one user highway, userHighway [X] .useSlot [Y]; Is the subscriber slot ID that can be assigned to one user highway, userHighway [X] .timeSlot [32] .mastSlot; is the mast slot ID assigned to that channel, and userHighway [X] .timeSlot [32] .mastPort; is the corresponding channel The mast port ID specified in. userHighway [X] .timeSlot [32] .timeSlot [Z]. slot; is a slot ID assigned to a subchannel of a corresponding channel, and userHighway [X]. timeSlot [32] .timeSlot [Z] .port; is a designated port ID per subchannel of the channel.

Next, the contents of the buffer structure of FIG. 9B written in a predetermined computer language (the structure part is omitted) and functions thereof will be described.

userSlot [Y] .useHwy [4]; Number of subscriber highways that can be occupied per slot

userSlot [Y] .muxPoint; Multiplied Points Per Slot

10 shows a grouping ID management buffer structure according to an embodiment of the present invention. In the following, the buffer structure of FIG. 10 is written in, for example, C language of a computer program language (the structure part is omitted), and a function thereof is described. In FIG. 10, the variable X is the maximum number of group IDs supported by the system, and Z is the maximum number of usable subtimeslots.

groupTable [X] .mastSlot; Mast Slot ID by Group ID

groupTable [X] .mastPort; Mast port ID according to group ID

groupTable [X] .subTimeSlot [Z] .slot;

groupTable [X] .subTimeSlot [Z] .port;

groupTable [X] .highway; Highway used per group ID

groupTable [X] .timeSlot; Channels used per group ID

groupTable [X] .destHighway; Link highways per group ID

groupTable [X] .destTimeSlot; Link channel connected per group ID

Among the items not described above, groupTable [X] .subTimeSlot [Z] .slot; is a designated slot ID per sub timeslot of a group ID, and groupTable [X] .subTimeSlot [Z] .port; is a sub of group ID. The port ID specified per timeslot.

11 illustrates a link multiplexing management buffer structure according to an embodiment of the present invention. In the following, the buffer structure of FIG. 11 is written in, for example, C language of the computer programming language (the structure part is omitted), and a function thereof is described. In FIG. 11, the variable X is the maximum number of links supported by the system, and Z is the maximum number of usable subtimeslots.

trkStsMuxLink [X] [32] .groupId; Group ID per link / channel

trkStsMuxLink [X] [32] .mastSlot; Link / Channel Mast Slot

trkStsMuxLink [X] [32] .mastPort; Link / Channel Mast Port

trkStsMuxLink [X] [32] .subTimeSlot [Z] .slot;

trkStsMuxLink [X] [32] .subTimeSlot [Z] .port;

Among the above-described items, trkStsMuxLink [X] [32] .subTimeSlot [Z] .slot; is the slot ID assigned to the link / channel / subchannel, and trkStsMuxLink [X] [32] .subTimeSlot [Z]. port; is a port ID assigned to the link / channel / subchannel.

4 is a flowchart for setting a highway when a subscriber card / port is activated. It should be noted that the access network apparatus has a plurality of subscriber slots, and it is possible to mount a subscriber card, that is, an LSDU card, in any subscriber slot. Multiple LSDU cards can use a single user highway. Therefore, when the LSDU subscriber is activated, it must first determine whether to multiplex with the existing one. In the following description, it is assumed that LSDU cards mounted in an access network device each have 5 ports, 16 subscriber slots, and 30 maximum types that can be multiplexed. To increase the type of service, the number of user highways and channels can be extended by that much. In the process of Fig. 4, when the LSDU card is first mounted on the access network device and the first port is activated, an arbitrary user highway is set, and when another card or another port is activated later, the previous value is retained. .

More specifically, in step 100, it is determined whether the first port of the card is activated. If not, in step 118, the port proceeds to select the highway occupied by the card. If it is active, it proceeds to step 102 to set the flag to " 0 ", and proceeds to step 104 to determine whether another card is alive. If not, proceed to step 108; if alive, proceed to step 106 to control the same highway as other cards. Then proceed to step 108. In step 108, it is determined whether the flag is "0", and if the flag is not "0", control proceeds to step 110 to select a new highway that is not in use. Thereafter, in step 112, recording is performed in the subscriber management buffer, and then the operation of the timeslot management procedure 1 is performed. The operation of the timeslot management procedure 1 will be described with reference to FIG.

5 is a flowchart for releasing a subscriber highway. Starting from the port deactivated state, in step 100, the highway is taken from the subscriber management buffer, and in step 202, it is determined whether another port is alive. If other ports are alive, set ACTFLAG to "1" and LASTFLAG to "1". If the other port is not alive in the determination of step 202, the process proceeds to step 206 to set ACTFLAG to "0" and LASTFLAG to "0".

Thereafter, in step 208, it is determined whether the ACTFLAG is "0", and if so, the process goes to step 210 to determine whether another card is alive. If the other card is alive, proceed to step 212 to clear the port multiplexing buffer, and then go to step 214. However, if the ACTFLAG is not " 0 " in step 208 and no other card is alive in the decision in step 210, the process proceeds directly to step 214. In step 214, it is determined whether LASTFLAG is "0". If LASTFLAG is "0", go to step 216 to clear the card / port multiplexing buffer and proceed to step 218. If LASTFLAG is not "0", go to step 218 immediately. In step 218, the time slot management procedure 2 is performed. The operation of the timeslot management procedure 1 will be described with reference to FIG.

6 illustrates a process of allocating a channel after a subscriber port establishes an active air user highway. From the provisioning made by the operator, the group ID and subtimeslot are taken from the configuration database to determine whether the group is the first port active or the second or more port active. The first active port becomes the master port of the group and performs all management around this port. The active ports are then managed only in sub timeslots.

The operation of the time slot management procedure 1 of FIG. 6 will be described in more detail. In step 300, a group ID and a sub time slot are taken from the DB, and in step 302, it is determined whether the first port is the same group. If it is the first port in the same group, proceed to step 304 to obtain a time slot, select its master, record it in the sub time slot management buffer, and proceed to step 308. If it is not the first port in the same group, the flow proceeds to step 306 to obtain a time slot and records it in the sub-time slot management buffer. In step 308, it is recorded in the subscriber management buffer.

The procedure of port deactivation of FIG. 7 is reversed from the active procedure of FIG. 6. When the mast port is deactivated, it is first determined whether there is another port to replace it, and when it is determined, the management of the mast port is transferred to another active port, and only itself is cleared. Finally, if the port being deactivated is a mast port, all the multiplexing related information is cleared. Only then will other subscribers be able to use that highway and channel.

The operation of the timeslot management procedure 2 in step 116 of FIG. 5 will be described in more detail with reference to FIG. 7. In step 400, the timeslot management procedure sets the highway, time slot, and sub time slots in the subscriber management buffer. And the DB, obtain the mast of the highway / time slot in step 402, and delete its own sub-time slot management buffer. After that, it is determined whether the port is a mast port in step 404, and if it is a mast port, the process proceeds to step 406 to determine whether another port is active. If the other port is active, go to step 408 to change the mast to another port. If the other port is not active, go to step 410 to delete all data of the group.

8 shows the flow of subscribers switching with multiplexed channels and links / channels. Switching is performed between channels in units of 64 Kbps. Therefore, the time slot and switching of the link channel and the subscriber should be performed. Instead of switching with all the multiplexed low-speed subscriber data, only the mast port of the mast slot should be switched.

Referring to FIG. 2 again, an example operation for subscriber multiplexing, for example, when the data transmission rate of five subscribers has 9600bps, the multiplexer 12 gives the same group ID under the control of the CCU 20. Assign subtimeslots from 0 to 4 in order. The switching of the switching unit 16 is managed by the CCU 20 so as to be performed between the subscriber serving as the mast port and the link / channel.

In the above description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the equivalent of claims and claims.

As described above, the present invention satisfies the X.50 standard, provides a low speed data service by mounting an LSDU card in an access network device, and enables a plurality of low speed data subscribers using a minimum bandwidth. According to the embodiment of the present invention described above, in addition to the DS0 (Digital Signal0) Class A service using the PSTN, Integrated Services Digital Network (ISDN), Integrated Digital Loop Carrier (IDLC), IDLC (Integrated Digital Loop Carrier) call service and 64 Kbps channel, DSOB-class low-speed data call services are also available in access network devices.

Claims (1)

A method for providing low speed data service in an access network device, the method comprising: A first management buffer for configuring a plurality of subscribers and a task and a procedure related to link control and call connection control to provide the low speed data service, and managing highways, channels, and subchannels for subscriber multiplexing; Configuring a second management buffer for group management for three subscribers, and a third management buffer for link multiplexing management, Using the task and procedure, the first, second and third management buffers, a frame is composed of a plurality of channels, and each of the channels is connected to the access network device and the plurality of low-speed subscribers having various transmission rates. And multiplexing the slow data into subchannels.