JP2000253471A - Interface control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to connect plural access networks with local exchanges by reducing the processing capacity of a V5 interface having multi- stage constitution. SOLUTION: At the time of receiving an LAPV5 frame from an access network(AN) 10 or a local exchange(LE), a LAYER2 terminating set 12a guarantees the transmission/reception of the LAPV5 frame. A Layer3 terminating set 12b terminates each LAPV5 protocol. The interface control device 12 reduces the processing of the terminating set 12b by converting an EF address to be used for the identification of an ISDN subscriber and an L3 address to be used for the identification of a PSTN subscriber by EF address conversion processing 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an interface control device for connecting a plurality of access networks and local exchanges.

[0002]

2. Description of the Related Art Conventionally, V5.1 is used for frames of ISDN subscribers under an access network (AN).
After terminating LAYER3 as an interface, V
5.2 Send a frame to the interface.
Conversely, for a frame from the local exchange (LE) for an ISDN subscriber under an access network (AN), the LAYER on the V5.2 interface side.
3 is terminated, and a frame is sent to the V5.1 interface side. Therefore, in the conventional method, V5.1
Each frame on the /V5.2 interface requires termination at the LAYER3 terminator.

[0003] In addition, for frames of PSTN subscribers under the control of an access network (AN), V
After terminating LAYER3 as a 5.1 interface, a frame is transmitted to the V5.2 interface. Conversely, for a frame for a PSTN subscriber under the control of the access network (AN) from the local exchange (LE), the frame is sent to the V5.1 interface 11 after terminating LAYER3 on the V5.2 interface side. . Therefore, in the conventional method, it is necessary to terminate each frame on the V5.1 / V5.2 interface with the LAYER3 terminator. In the case of the PSTN protocol, a large amount of signaling information such as a digit report from a subscriber fluctuates, so that a considerable processing capability between LAYER2 and LAYER3 is required.

[0004]

As described above, in the prior art, the processing capability between the LAYER2 and the LAYER3,
Especially since the processing capacity of LAYER3 is considerably required,
In the case of a multistage configuration, there is a problem that a load is imposed on the processing capacity and it is difficult to connect a plurality of access networks and local exchanges.

The present invention has been made in view of the above circumstances, and provides an interface control device capable of connecting a plurality of access networks and local exchanges by reducing the processing capacity of a multistage V5 interface. The purpose is to do.

[0006]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, an access network directly accommodating a subscriber and a local exchange are connected to a V5.
In the interface control device connected by the layer 2 terminating means and the layer 3 terminating means in the interface, the layer 2 terminating means mutually converts an EF address used for identification of an ISDN subscriber between the access network and the local exchange. An address translation unit is provided, and the frame is transmitted to the partner interface without being terminated by the layer 3 termination unit.

[0007] According to the second aspect of the present invention, the first aspect is provided.
2. The interface control device according to claim 1, wherein said layer 2 terminating means is used for identifying a PSTN subscriber between said access network and said local exchange.
An address translation means for translating the three addresses into each other is provided, and a logical CH used in the layer 2 terminating means is exchanged to be transmitted to a partner interface.

[0008] According to the third aspect of the present invention, the first aspect of the present invention.
In the interface control device described above, the EF address is set for each predetermined range.

According to the present invention, the ISDN frame between the V5.1 and V5.2 interfaces is transmitted to the E-
By allocating the F address and transmitting the frame to the partner interface without terminating, the termination processing at Layer 3 and Layer 2 due to V5 ISDN frame relaying is reduced. Therefore, it is possible to connect a plurality of access networks and local exchanges by reducing the processing capacity of the multistage V5 interface. In the present invention,

[0010]

Embodiments of the present invention will be described below with reference to the drawings. A. Configuration of Embodiment FIG. 1 is a block diagram showing a schematic configuration of a V5 interface according to an embodiment of the present invention. In the figure, an access network (AN) 1 directly accommodates subscribers 6, 7, 8, 9 such as ISDN subscribers and analog subscribers, and subscribes to a local exchange (LE) 2 using a V5 message. Sends the user's control information. Reference numeral 3 denotes an interface point on the access network (AN) 1 side. The local exchange (LE) 2 is a device that terminates a V5 message of the access network (AN) 1.
Reference numeral 4 denotes an interface point on the local exchange (LE) 2 side.

The V5 interface is 2.048 Mb
The basic unit is ps (64 kbps × 32 time slots), and the voice of the telephone and the bearer data of the B channel data of the ISDN terminal are all transmitted in one time slot (64 kbps). Control data between the local exchange (LE) 2 and the access network (AN) 1 is transmitted using a specific TS (time slot) called a C-ch (communication channel).

[0012] Of the 32 time slots, TS0 is a time slot for frame synchronization, TS1 to TS15, TS1.
7 to TS31 are time slots for bearer data, TS1
Reference numeral 6 denotes a time slot dedicated to C-ch. Also, T
In S15 and TS31, C is determined by the traffic of the control signal.
-Ch can be assigned. C-ch (communication channel) data is ISDN L
A protocol called LAPV5 based on the APD protocol is used, and the access network (A
N) The Dch of an ISDN subscriber under one is also converted into a LAPV5 frame and transmitted on the same Cch.

Next, FIG. 2 is a conceptual diagram showing the LAPV5 frame format. FIG. 3 shows the Envelope Function Address shown in FIG.
It is a conceptual diagram showing the format of the part of (EF address). As shown in FIG. 2, the LAPV5 frame has an address field of an EF address portion, information of a data portion corresponding to the EF address, and a frame check sequence (FC
S), and a flag (FL) is provided at the beginning and end of the frame.
AG).

An EF address, which is an address field, is composed of 13 bits as shown in FIG. The contents indicated by the EF address are ISD from 0 to 8175
User port information indicating N Dch, 8176 to 81
80 is LAPV5 protocol information, 8181 to 8191
Is reserved. For the contents of the LAPV5 protocol of 8176-8180, 8176 is an analog telephone (PSTN: Pu).
blic Switched Telephone Network) signaling information, 8177 is V5 interface connection information (Co
8178 is information of a bearer channel connection (BCC) protocol, 8179 is information of a protection protocol,
Reference numeral 8180 denotes link control protocol information.

The V5 interface has V5.
1. There is a V5.2 interface. The V5.1 interface uses only the ISDN, PSTN, and CONTROL protocols of the LAPV5 protocol, and the V5.2 interface uses the above-described LA.
Uses all PV5 protocols. A feature of the V5.1 interface is that there is no line consolidation on the V5.1 interface with the subscribers 6,7,8,9. That is, although the TS on the V5.1 interface and the number of subscribers are one-to-one,
In the V5.2 interface, since there is a line concentrator, a procedure for allocating a TS to a subscriber is required.

FIG. 4 is a block diagram showing a network configuration to which the interface control device according to the present embodiment is applied. In the figure, access networks (AN) 10a to 10e (hereinafter collectively referred to as 10)
It is connected to the interface control device 12 via the transmission line of the 5.1 interface 11. The interface control device 12 includes a V5.2 interface 13
Is connected to the V5 exchange 14 via the transmission line of the. 1
4 is a local exchange (LE) connected to the exchange network 15
V5 switching network.

FIG. 5 is a block diagram showing a functional configuration of the interface control device. Parts corresponding to those in FIG. 4 are denoted by the same reference numerals, and description thereof is omitted. The interface control device 12 is roughly classified into LAYER2
It comprises a termination device 12a and a LAYER3 termination device 12b. The LAYER2 terminating device 12a is connected to the access network (AN) 10 or the local exchange (L).
E) Upon receiving the LAPV5 frame from 14, LA
Transmission and reception for the PV5 frame are guaranteed. LAYER
The three terminating device 12b terminates each LAPV5 protocol. The feature of the interface control device 12 is that the IS
The EF address used to identify the DN subscriber and the L3 address used to identify the PSTN subscriber are converted by an EF address conversion process 20 described later, so that the LAYER
The purpose is to reduce the processing in the three terminal device 12b.

Next, FIG. 6 shows an access network (A
It is a conceptual diagram which shows the processing route of the LAPV5 frame of ISDN subscriber accommodated under N). In the conventional method, as described above, the access network (AN) 1
0 for the frame of the ISDN subscriber under the control of V5.
After terminating LAYER3 as one interface 11, a frame is transmitted to the V5.2 interface 13. Conversely, for the frame from the local exchange (LE) 14 to the ISDN subscriber under the certain access network (AN) 10, the LAYER 3 is terminated on the V5.2 interface 13 side, and then the frame is transmitted to the V5.1 interface 11 side. Is sent. Therefore, in the conventional method, the illustrated path P1, ie, V
Each frame on the 5.1 / V5.2 interfaces 11 and 13 needs to be terminated by the LAYER3 terminator 12b.

On the other hand, in the present embodiment, LAYE
If there is no processing to be performed at the R3 level and only the frame is sent to the interface on the other end, the LAYER3
Termination at the level is no longer necessary. In this interface device 12, the exchange of information between LAYER2 and LAYER3 is reduced by reducing the end portion of LAYER3. A route P2 shown in FIG. 6 is a route in the interface device 12. In order to perform this process, an EF address conversion process (mapping) 2 for converting an EF address used for ISDN subscriber identification 2
0 must be stored in the LAYER2 terminating device 12a.
When a plurality of V5.1 interfaces are multiplexed into a plurality of V5.2 interfaces, if the EF address is unique among the plurality of V5.1 interfaces, the ISDN frame from the V5.1 interface is mapped to the mapping destination V5.2. It only needs to be sent out on the interface. FIG. 7 shows a mapping example in this case.

[0020] The PSTN subscriber is identified by the L3 address in the frame. In the PSTN protocol, since the EF address is fixed and there is only one on each V5 interface, LAYER2 must be terminated to identify the source subscriber and send it to the other party's V5 interface. In PSTN, unlike ISDN, V
Since there is not one link (logical CH) per subscriber on the 5.1 / V5.2 interface, frames cannot be transmitted to the other side at the LAYER2 level. Therefore, in the present interface device 12, after terminating LAYER2, an EF address conversion process (mapping) is performed in which the L3 address in the frame is checked to determine on which V5 interface the frame should be transmitted.
20 and the LAYER2 protocol termination function 21
By having it in the YER2 termination device 12a, LAYER
The exchange of information between the two terminating devices 12a and the LAYER3 terminating devices 12b is reduced.

Next, FIG. 8 shows an access network (A
N) is a block diagram showing a processing route of a LAPV5 frame of a PSTN subscriber accommodated under it. In the conventional method, for a frame of a PSTN subscriber under the control of an access network (AN) 10, after terminating LAYER 3 as a V5.1 interface 11,
5.2 Send the frame to the interface 13. Conversely, for a frame from a local exchange (LE) 14 to a PSTN subscriber under the control of the access network (AN) 10, the V5.2 interface 13 terminates the LAYER 3 and then passes the V5.1 via the route P3 to the V5.1. The frame is transmitted to the interface 11 side. That is, according to the conventional method, LAYE is applied to each frame on the V5.1 / V5.2 interface.
Termination at the R3 termination device 12b is required. In the case of the PSTN protocol, since a lot of signaling information such as a digit report from a subscriber flies, LAYER2, LAYER
Significant processing power between ER3 is required.

On the other hand, in the interface device 12 according to the present embodiment, an EF address conversion process (mapping) 20 for identifying the access network (AN) 10 and the local exchange (LE) 14 is provided in the LAYER2 termination device 12a. LAYER2 protocol termination function 21
With this configuration, the exchange of information between LAYER2 and LAYER3 is eliminated, and the processing capacity is reduced. FIG.
, The path P4 is a PSTN frame route in the interface device 12.

FIG. 9 shows the interface device 1 of the present invention.
FIG. 2 is a conceptual diagram showing a mapping example when a PSTN subscriber is accommodated under an access network (AN) 10 under the control of an access network (AN) 10; This is a mapping table similar to the ISDN EF address shown in FIG. 10, but the AN / LE number part is a link number (logical CH number handled in the LAYER2 terminating device 12a). The mapping example when the L3 address is not unique is the same as the mapping example shown in FIG.

In the control protocol (CONTROL protocol), the COMMON CONTROL protocol which is a control protocol for the AN / LE device and the IS
There is a PORT CONTROL protocol which is a control protocol for DN / PSTN subscribers.
The same processing as in the STN protocol is performed by this PORTC.
It can be performed by the ONTROL protocol. PSTN
As with the protocol, the PORT CONTROL
Although the L3 address field in the frame is used for subscriber identification, ISDN subscribers and PSTN subscribers also use
Use that field. By having the mapping of the L3 address field in the LAYER2 terminating device 12a, the exchange of information between the LAYER2 and the LAYER3 can be reduced. The mapping example is P
The description is omitted because it is the same as the STN mapping.

FIG. 10 shows a protocol stack of the ISDN frame in the present apparatus. FIG.
4 shows a protocol stack of the TN, CONTROL (PORT CONTROL) frame in the apparatus.

B. Next, the overall operation of the present embodiment will be described in detail. Here, FIG. 12 shows an access network (AN).
FIG. 7 shows an example of general call processing of a subordinate ISDN subscriber.
FIG. 7 is a sequence diagram based on the mapping shown in FIG. FIG.
In FIG. 7, the access network (AN) 10
, The local exchange (LE) 14
Will be described as the LE number “4” shown in FIG. A and B in the figure are LAYER2 terminating devices 12a in the present apparatus, where A is the AN side and B is the LE side.

First, the access network (AN) 10
By a call from an ISDN subscriber under
[6] Link setting request frame S with EF address = 1
ABME is layer2 of LAYER2 terminator 12a
_AnA. LAYER that received the frame
The layer2_anA of the two-terminal device 12a searches for a frame to be transmitted to the V5.2 interface with reference to the mapping table of FIG. FIG.
Is mapped such that the local exchange (LE) number is "4" and transmitted with the EF address = 1.
yer2_anA is [7] without terminating LAYER2.
Setting request frame SABM with EF address = 1
E is sent to the local exchange (LE) 14 as it is.

The local exchange (LE) 14 having received the link setting request frame SABME returns a frame UA [8] which is a response to the request. LAYER2
The layer2_leB of the terminating device 12a searches the mapping table of FIG. 7 to determine whether or not the frame should be sent out on the partner V5 interface. In the mapping table of FIG. 10, since mapping is performed so that the access network (AN) number is “1” and EF address = 1 is transmitted, layer2_leB of the LAYER2 terminating device 12a is LAYER2.
, And transmits the link setting response frame UA [9] to the access network (AN) 10 as it is. The same processing is performed on the subsequent ISDN frame whose EF address is “1”.

In the middle of the sequence, a frame AL of [14] for allocating TS with a BCC protocol frame
For the LOCATION and the ALLOCATION COMP of the frame [16] which is the response, the LAY
Terminates at ER2 and LAYER3. As described above, the access network (AN) 10 and the local exchange (LE) 14 exchange signaling information without being aware of the interface device 12 in the ISDN protocol.

Next, FIG. 13 is a sequence diagram based on the mapping of FIG. 9 taking as an example the general call processing of a PSTN subscriber under the control of the access network (AN) 10. The access network (AN) 10 has a logical number “0” in FIG. 9, and the local exchange (LE) 14 has
Description will be made assuming that the logical number is "5" in FIG. A and B in the figure are the LAYER2 terminating devices 12a in this device, and A is AN
The side B is the LE side.

First, the access network (AN) 10
By a call from an ISDN subscriber under
The PSTN protocol frame ESTABLISH with the L3 address = 9 in [6] is sent to the layer2_anA of the LAYER2 terminating device 12a. Layer2_anA of the LAYER2 termination device 12a that has received the frame
Terminates LAYER2 and returns the frame ESTABLIS
In order to notify that H has been received normally, the frame RR of [9] is transmitted to the access network (AN) 10. At the same time, the layer of the LAYER2 termination device 12a
In 2_anA, whether the terminated frame is a frame to be transmitted to the V5.2 interface side is searched by the L3 address in the frame. In the mapping table of FIG. 9, the local exchange (LE) logical number "4"
Since the mapping is performed so as to be transmitted with the address = 10, the layer2_a of the LAYER2 terminating device 12a is
The nA transmits the frame on the other party's logical CH4 without passing the frame to the LAYER 3 terminating device 12b.

The layer2_leB of the LAYER2 terminating device 12a that has received the frame processes the frame as a frame coming from the LAYER3, and sends the frame ESTA of [7] to the local exchange (LE) 14 side.
Send BISH. Upon receiving the frame ESTABLISH of [7], the local exchange (LE) 14 sends out a frame RR of [10] to inform that the frame has been normally received by LAYER2. The local exchange (LE) 14 transmits the frame ESTABL of [7].
LAYER3 level response to ISH [1
1] of the frame ESTABLISH ACK. The layer2_leB of the LAYER2 terminating device 12a that has received the frame transmits a frame RR of [13] indicating that the frame has been normally received at the LAYER2 level.

At the same time, l of the LAYER2 terminator 12a
In ayer2_leB, the terminated frame is V5.1
The L3 address in the frame is searched for a frame to be transmitted to the interface side. In the mapping table of FIG. 9, the mapping is performed so that the logical number “0” is transmitted to the access network (AN) 10 with the L3 address = 9.
Layer2_leB of LAYER3 termination device 12
The frame is transmitted to the other party's logical CH0 without passing the frame to b. The layer2_anA of the LAYER2 terminating device 12a that has received the frame processes the frame as a frame coming from the LAYER3, and sends the frame ESTABLE to the local exchange (LE) 14 side.
Send SH ACK. The subsequent PSTN protocol is a repetition of the above process.

A frame [15] for allocating TS by the BCC protocol in the sequence.
N and the response [17] frame ALLOCA
LAYER2, LAY for TION COMP
ER3 is terminated. Thus, the access network (AN) 10 and the local exchange (LE) 14
According to the PSTN protocol, the LATN device 12a in the interface device 12 does not pass through the LAYER3 termination device 12b.
Signaling information is exchanged within the YER2 terminating device 12a.

Note that a control protocol (CONTROL) for controlling the subscriber
In this case, the processing is the same as that of the above-mentioned PSTN protocol, and thus the description is omitted.

C. Another Embodiment Next, another embodiment of the present invention will be described. Incidentally, the mapping conversion processing 20 performed in the LAYER2 terminating device 12a requires a large amount of mapping memory.
Therefore, the processing can be further reduced by using only one EF address on the V5.1 interface and the V5.2 interface. FIG. 14 shows a mapping example. In this case, since the EF address is set for each predetermined range, it is not necessary to have mapping for all EF addresses.
The search time in the terminal device 12a can be reduced. Further, it is possible to further reduce the processing by forming this mapping search processing into an LSI.

[0037]

As described above, according to the present invention,
Since the EF address is assigned to each subscriber for the ISDN frame between the V5.1 and V5.2 interfaces and the frame is transmitted to the partner interface without terminating, the Layer 3 and the Layer 2 by the frame relaying of the V5 ISDN are used. Is obtained. Also, PST
N, in a Control (port Control) protocol, an L3 address is assigned to each subscriber,
V5 PSTN, Contr
There is an advantage that the termination processing in Layer 3 due to the frame switching of the l (port Control) protocol can be reduced. Furthermore, since the search processing in Layer 2 is simplified by setting mapping data of the L3 address for performing frame switching, V5 PSTN, Contr
ol (port Control) protocol when using L3 address provisioning data setting La
There is an advantage that the efficiency of the frame switching of yer2 can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a V5 interface according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing an LAPV5 frame format.

FIG. 3 is a conceptual diagram showing a format of an EF address part.

FIG. 4 is a block diagram showing a network configuration to which the interface control device according to the embodiment of the present invention is applied;

FIG. 5 is a block diagram illustrating a functional configuration of an interface control device.

FIG. 6 is a conceptual diagram showing a processing route of a LAPV5 frame of an ISDN subscriber accommodated under an access network (AN).

FIG. 7: IS under an access network (AN)
It is a conceptual diagram which shows the example of a mapping when a DN subscriber is accommodated.

FIG. 8 is a block diagram showing a processing route of a LAPV5 frame of a PSTN subscriber accommodated under an access network (AN).

FIG. 9: PS under the access network (AN)
It is a conceptual diagram which shows the example of a mapping when a TN subscriber is accommodated.

FIG. 10 is a conceptual diagram showing a protocol stack of an ISDN frame in the present apparatus.

FIG. 11 PSTN, CONTROL (PORT C
FIG. 3 is a conceptual diagram illustrating a protocol stack of the present invention for an (ONTROL) frame.

FIG. 12 IS under an access network (AN)
FIG. 8 is a sequence diagram based on the mapping shown in FIG. 7, taking a general call processing of a DN subscriber as an example.

FIG. 13 PS under the access network (AN)
FIG. 10 is a sequence diagram based on the mapping of FIG. 9 taking a typical call processing of a TN subscriber as an example.

FIG. 14 is a conceptual diagram illustrating an example of mapping an EF address according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Access network 11 V5.1 interface 12 Interface control device 12a LAYER2 termination device (layer 2 termination device) 12b LAYER3 termination device (layer 3 termination device) 13 V5.2 interface 14 local exchange 20 EF address conversion process (EF address conversion device) ) 21 LAYER2 protocol termination function

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04Q 3/42 104 H04L 13/00 309A 5K101 9A001 F term (Reference) 5K030 HC02 HC04 HD09 KA13 5K034 EE13 HH01 HH02 KK01 KK21 KK27 5K050 BB01 BB03 BB12 BB14 DD27 DD28 EE32 EE33 EE36 5K051 CC01 CC04 DD02 DD09 DD13 JJ04 5K069 CA01 CA03 CB03 CB04 CB08 5K101 LL03 TT01 9A001 BB04 CC04

Claims (3)

[Claims] 1. An interface control apparatus for connecting an access network directly accommodating a subscriber and a local exchange by a layer 2 terminating means and a layer 3 terminating means in a V5 interface, wherein said layer 2 terminating means comprises: An interface, comprising: an address translation unit for mutually translating an EF address used for identification of an ISDN subscriber with the local exchange, wherein a frame is transmitted to a partner interface without being terminated by the layer 3 termination unit. Control device. 2. The method according to claim 1, wherein said layer 2 terminating means comprises a PST between said access network and said local exchange.
2. The communication system according to claim 1, further comprising address conversion means for mutually converting L3 addresses used for identification of N subscribers, wherein the logical CH used in said layer 2 terminating means is exchanged and transmitted to a partner interface. Interface control device. 3. The interface control device according to claim 1, wherein the EF address is set for each predetermined range.