JP2551061B2 - ISDN subscriber line switching system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of using a subscriber line in ISDN (Integrated Services Digital Network), and more particularly to a plurality of subscriber lines.
The present invention relates to a subscriber line switching system in which a plurality of subscriber lines are selected and used in a user's house for direct communication with ISDN.

(Prior Art) Regarding the interface between the user and the network in ISDN, CCITT (International Telegraph and Telephone Consultative Committee) is actively promoting standardization, and the result is summarized as CCITT recommendation. In these recommendations, two types of interfaces called a basic interface and a primary group interface are specified, and it is assumed that a subscriber line is drawn into the user's house for each required interface.

First, the contents of the CCITT recommendation that defines the ISDN interface for each subscriber line will be outlined.

First, a list of terms and abbreviations frequently used in ISDN are listed below.

<B channel> An information channel of 64 kbit / s in ISDN. By exchanging the circuit, it is connected to the desired communication partner through the B channel, and information of 64 kbit / s or less can be exchanged. The B channel may be used to access the packet switching network.

<D channel> A channel for transmitting a D channel message for call control and a user packet. In the basic interface
16 kbit / s, 64 kbit / s are allocated in the primary group interface.

<Basic interface> One of the interface types specified between ISDN and user premises. Two B channels (64 kbit / s) and one D channel (16 kbit / s) can be set on one subscriber line.

<Primary group interface> An interface for accommodating user equipment such as PBX in ISDN. In Japan and the United States, the transmission speed is 1.54
It is 4 Mbit / s. For example, 23 B channels and 1 D channel (64 kbit / s) can be multiplexed. On the other hand, in Europe, the transmission speed is 2.048Mbit / s,
30 B channels and 1 D channel are multiplexed. In addition,
H0 (384kbit / s), H11 with higher information speed than B channel
(1.536 Mbit / s) and H12 (1.920 Mbit / s) information channels may be multiplexed.

<Network Termination Device (NT)> A device that terminates the subscriber line in the user's home.
There are NT1 for satisfying the layer 1 specifications that specify electrical / physical conditions, and layer 2 for defining the D channel message formatting and error resending method, and NT2 for satisfying the layer specifications above. Specific examples of NT2 include PBX and LAN.

<Home equipment (TE)> This is a service terminal installed in the user's home, and is classified into an ISDN home equipment (TE1) and a non-ISDN home equipment (TE2). When connecting TE2 to ISDN, an interface converter (TA) is used.

<Terminating equipment (ET)> Equipment attached to the ISDN switching equipment side and terminating the subscriber line from the user's premises. Has layer 2 and 3 functions.

<U point interface> An interface on a subscriber line that connects ISDN and a network terminating device (NT1) having a layer 1 function.

<S / T point interface> The S point interface is an interface between a network terminating device (NT1) having a layer 1 function or a network terminating device (NT2) having a layer 2 or more function and a home equipment (TE). . The T-point interface is both network termination devices (NT1 and N
Interface between T2). However, if NT2 is not used, the S point and T point interfaces are equivalent. The specifications for these interfaces are given in CCITT Recommendation I.400.
It is standardized as a series. It defines the lower 3 layers of the OSI (Open Systems Interconnection) 7 layer model.

<LAPD (Link Access Procedure on the Dchannel)> A protocol applied to the D channel layer 2 in the ISDN user / network interface. LAPB (Link Access Procedure, Balanc) for packet switching network (X.25)
ed), but some functions such as 1-to-n communication and broadcasting are added to meet the new requirements of ISDN.

FIG. 1 shows a block diagram of a conventional basic interface.

In the figure, 1 ₁ to 1 _i are home equipment (hereinafter referred to as “TE”), 2 is a network terminating device having a layer 1 function (hereinafter, referred to as “TE”)
"NT1"), 3 is an exchange terminating device (hereinafter "ET")
Is called). It should be noted that 11 ₁ to 1 _i are the non-terminals of the TE1 itself when the home equipment for ISDN (hereinafter referred to as "TE1") is used.
When an ISDN home device (hereinafter referred to as “TE2”) is used, it means a combination of TE2 and an interface conversion device (hereinafter referred to as “TA”). The CCITT Recommendation defines NT1 as the boundary of the S point or T point interface.
The side is classified as network (ISDN) side equipment, and the NT2 and TE sides described later are classified as user side equipment.

FIG. 2 shows a block diagram of a conventional primary group interface.

In the figure, (1-1) ₁ to (1-j) _i is a home equipment (TE), 2 is a network terminating device (NT) having a layer 1 function.
1), 3 is an exchange terminating device (ET), and 4 is a network terminating device (NT2) having a layer 2 or higher function.

As is apparent from FIGS. 1 and 2, the difference between the basic interface and the primary group interface is that the network termination device (NT2) between the home equipment (TE) 1 and the network termination device (NT1) 2 is different. 4 is present or absent. In the configuration of the primary group interface, the user side equipment has a network terminating device (NT2) 4. Note that the CCITT Recommendation specifies detailed specifications in detail, but it is omitted here.

(Problems to be Solved by the Invention) As described above, the CCITT Recommendations specify specifications for basic and primary user / network interfaces on the assumption that each system has one system. .

However, if there are multiple telecommunications carriers that provide domestic and international telecommunications services in the future, multiple subscriber lines set for each telecommunications carrier will be used for each communication within the user's home. It is expected that the need will arise. Of course, according to the current CCITT recommendation, if independent home wiring for each subscriber line is prepared, there is no need to switch and use. However, if the user wants to use the equipment on the user side for general purposes without being aware of the telecommunications carrier, it is necessary to change the physical connection of the equipment on the user side to the communication type, resulting in communication efficiency or artificial misconnection. The problem of occurs.

(Objects and Features of the Invention) The present invention has been made in view of the above-mentioned problems of the conventional technology, and is a subscriber line switching system having a function of commonly using individual user side equipment for all subscriber lines. The purpose is to provide.

A feature of the present invention is that the user accommodating a subscriber line connecting each of the ISDNs and user-side equipment in the user's premises to communicate with a plurality of ISDNs having at least a hierarchy of layer 1, layer 2 and layer 3. In the house, the layer 1,2,3 function with each of the user side equipment and the layer 1,2,3 function with each of the ISDN and the D channel message or packet in the layer 3 are associated with each subscriber line. Or each layer with the ISDN
Call processing means for associating D channel messages and packets in the 1, 2 and 3 functions and the layer 3 with each of the subscriber lines, and for performing the route division for each subscriber line with respect to the information channel A switch means is provided, and by determining the contents of the layer 3 from the call processing means and controlling the switch means, the D for call control and packet transmission is selected according to the ISDN destination to which communication is set. The signal on the channel and on the information channel for user data transmission is switched to the subscriber line between the desired ISDN and the user side equipment.

(Structure of the Invention) Hereinafter, the present invention will be described in detail with reference to the drawings. In the following description, the configuration of the basic interface will be described as an example, but it can be applied to the primary group interface.

(Embodiment 1) FIG. 3 is a first embodiment according to the present invention, and FIG. 3 (a) is a subscriber according to the present invention when using in-home wiring of k system and m subscriber lines. FIG. 3 (b) is a block diagram of the subscriber line switching device according to the present invention, showing the positioning of the line switching device. In FIG. 3A, (1-1) ₁ to (1-k) _i is TE, 2-1 to 2-
m is an NT1 for each subscriber line, 3-1 to 3-m is an ET connected to each subscriber line, and 5 is a subscriber line switching device which is a feature of the present invention. According to the present invention, a subscriber line switching device is inserted between the home equipment (TE) and the network terminating device (NT1), and the subscriber line is selected according to the communication content to transmit necessary information. ing. Although not shown, in the primary group interface, a subscriber line switching device is inserted between two types of network terminators NT1 and NT2. Therefore, the subscriber line switching device according to the present invention is
NT1, NT2 and TE will offer the great advantage of being able to switch and use the subscriber lines as appropriate without making any changes.

In FIG. 3 (b), 7-1 to 7-k are user-side interface units facing individual home systems, 8-1 to 8-m are network-side interface units facing individual NT1s, respectively.
9-1 to 9-k are LAPD processing devices that perform protocol control functions such as error retransmission of layer 2 with TE, and 9-1 to 9-m are ETs to which individual subscriber lines are connected. Between the TE and ET, the processing unit performing the layer 2 function between the two, deciphers the contents of the D channel message packet in the layer 3 transferred between the TE and ET and determines which subscriber line to select. A layer 3 call processor, 11 is a switch for reconnecting information channels based on an instruction from the call processor 10, 20 is a user side interface, and 30 is a network side interface. In the above embodiment of the present invention for the basic interface, the user side interface 20 and the network side interface 30 are equivalent to the S / T point interface. Further, since the user side interface section 7 has the network side layer 1 function in the S / T point interface and the network side interface section 8 has the user side layer 1 function in the S / T point interface, the user is a subscriber according to the present invention. Communication can be performed without being aware of the use of the line switching device. Of these components, except for the layer 3 call processor 10 and the switch 11, already for ISDN
It is being developed in various fields as an LSI. The layer 3 call processor 10 is for grasping the contents of the D channel message packet and is constructed based on a CPU equipped with software. The switch 11 is a matrix switch or gate widely used in TAs and exchanges. -It can be realized by an array or the like. Further, it should be noted that the NT1 function can be integrated into the network side interface unit 8 of the subscriber line switching device.

The operation outline of the subscriber line switching device according to the present invention is as follows.

-Calling- (1) The layer 3 call processor 10 detects the contents of the message and packet on the D channel from the TE including the address of the communication partner.

(2) The call processor 10 determines which ISDN is targeted for the communication requested to originate, and activates the call setting for the desired ISDN.

(3) Call management is performed by the call processor 10, and the information channel B is relayed via the switch 11 and the messages and packets on the D channel are relayed to individual subscriber lines based on the call management information.

-Incoming Call- (1) Messages and packets on the D channel coming from each ISDN are relayed by the layer 3 call processor 10 and transferred to the TE.

(2) Call management is performed by the call processor 10, and the information channel B is connected to the TE via the switch 11.

When the primary group interface is considered, (i) the user side interface 20 is equivalent to a normal T-point interface, (ii) the transmission speed of the D channel is 64 kbit / s, (iii) 3.) The block configuration of the subscriber line switching device according to the invention is exactly the same as in FIG. 4, except that the switching function at the primary group level for the information channel is performed.

In the above, the embodiments of the present invention for the basic and primary interfaces are described. For example, when the interfaces are different for each subscriber line, that is, when it is required to use the interfaces in combination, This can be dealt with by appropriately combining the respective components of the user-side interface unit 7, the network-side interface unit 8, the LAPD processor 9, the call processor 10 and the switch 11 shown in FIG. 3 (b) with their respective interfaces. It is clear that

(Embodiment 2) Next, a case where the functions of the subscriber line switching device 5 described above are integrated into user equipment (TE, TA, NT2) will be described.

FIG. 4 is a second embodiment according to the present invention, and FIG. 4 (a) is intended for a basic interface, k system home wiring, and m subscriber lines, and functions as an ISDN home equipment (TE1). FIG. 4 (b) shows a subscriber line switching apparatus according to the present invention when the above are integrated. In FIG. 4 (a), 6 is a subscriber line switching device integrated into TE1, and the others are the same as in FIG. 3 (a).

In this embodiment, the TE1 is modified, but as will be described later, the modification has an advantage that the function is limited to a slight functional extension. In addition, non-ISDN home equipment (TE2)
When using, for the interface device (TA),
When a network terminating device (NT2) having a layer 2 or higher function is used, the present invention can be achieved by expanding the function of NT2 itself.

FIG. 4 (b) is a block diagram of the subscriber line switching device according to the present invention integrated with the user side equipment (TE1, TA, NT2) functions. In the figure, 8-1 to 8-m perform the layer 2 function between each NT1 and the facing network side interface section, and 9-1 to 9-m with the ET to which each subscriber line is connected. LAPD processor 10 for decoding the contents of the D channel message packet in layer 3 transferred between TE and ET, and determining which subscriber line to select, the layer 3 call processor, 11 is a call processor 10
Switch that switches the information channel based on the instructions of
40 is an interface with the information channel inside the user side equipment, and 50 is an interface with the D channel inside the user side equipment. Of these, 8 and 9 are functions that the user side equipment owns in advance, and it is sufficient to prepare the required subscriber line segments. 10 can be realized by expanding the functions of software installed in the user equipment in advance. Further, the switch 11 has the same function as that which is generally mounted because the switch is used by the user side equipment to select the connection destination information channel.

Note that the difference from the first embodiment in terms of configuration is the LAPD that implements a protocol control function such as error retransmission of the layer 2 between the user side interface units 7-1 to 7-k and the TE facing each home system. The processing devices 9-1 to 9-k are not necessary, and other configurations and operations are the same.

(Effects of the Invention) As described above, according to the present invention, by providing the subscriber line switching device inside the user's house accommodating the plurality of subscriber lines provided for directly communicating with the plurality of ISDNs, the user side The equipment can be shared by all subscriber lines, which not only prevents human error in operation but also prevents communication efficiency. In addition, the effect is great because there is no change to the CCITT recommendation compliant home appliances and network terminating equipment, or it can be applied with some functional expansion.

[Brief description of drawings]

FIG. 1 is a block diagram of a conventional ISDN basic interface, FIG. 2 is a block diagram of a conventional ISDN primary group interface, and FIGS. 3 (a) and 3 (b) are the first embodiment according to the present invention. FIG. 4A and FIG. 4B are block diagrams of a subscriber line switching device, which are a second embodiment according to the present invention, and show a subscriber line switching device in which a subscriber line switching function is integrated into user equipment. It is a block diagram. 1 ₁ to 1 _i …… In-home equipment, 2,4 …… Network terminating device, 3 …… Switch terminating device, 5 …… Subscriber line switching device, 6 …… Subscriber line switching integrated with user side equipment functions Equipment, 7-1 to 7-k ... User side interface section, 8-1 to 8-m ... Network side interface section, 9-1 to 9-k, 9-1 to 9-m ... LAPD processing apparatus , 10 ... Layer 3 call processor, 11 ... Switch, 20 ... User side interface, 30 ... S / T point interface, 40 ... Information channel interface, 50 ... D channel interface.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiko Ito 2-3-2 Nishishinjuku, Shinjuku-ku, Tokyo International Telegraph and Telephone Corporation (72) Inventor Takuro Muratani 2-3-3 Nishishinjuku, Shinjuku-ku, Tokyo No. 2 International Telegraph and Telephone Corporation (56) References Japanese Patent Laid-Open No. 63-9400 (JP, A)

Claims (1)

(57) [Claims] 1. In a subscriber line switching system for connecting a plurality of ISDNs having at least layers 1, 2, and 3 to a user-side equipment in a user's premises, a layer 1 for each user-side equipment is provided. Leia 2 Leia 3
Correspondence between layer 1 and layer 2 and layer 3 function and D channel message and packet in layer 3 to each subscriber line or each ISDN
Call processing means for associating the DLR message and packet in the layer 1, layer 2, and layer 3 functions with the DN with each of the subscriber lines, and one for each subscriber line for the information channel A call control, a packet is provided in accordance with an ISDN destination to which communication is set, by having switch means for performing route division, determining the contents of the layer 3 from the call processing means and controlling the switch means. D for transmission
A subscriber line switching system characterized in that signals on a channel and an information channel for transmitting user data are configured to be switched to a subscriber line between a desired ISDN and a user side equipment.