JPH03247141A - Flow control system - Google Patents

Abstract

PURPOSE:To reduce a range affected by a fault by sending a receive not-ready frame representing disabled reception when an information frame including transmission information of a terminal equipment is detected on a logic link during a fault of a transmission line and sending a receive ready frame representing enable frame reception at recovery. CONSTITUTION:When a fault of a transmission line 14 or a fault of a host device 16 is detected by a fault detection circuit 9, a receive not-ready(RNR) frame representing disabled reception is sent to an information (I) frame as a data sent from a terminal equipment by using a logical link identified by SAPI=0 on all subscriber lines. A logical link identified by the SAPI at recovery is used and an RR frame is sent to an l frame as a data sent from the terminal equipment to inform it that the data is receptible to the terminal equipment.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a flow control method, and in particular to a flow control method that detects a fault in a transmission path or a fault in a higher-level device for each service access point identifier, and controls the reception state of a terminal. Regarding control method.

[Conventional technology]

In the conventional flow control method, as shown in the professional diagram of FIG.
Accommodates SDN basic access subscriber lines 22, 23, 24, and 15DN basic access subscriber lines 22, 2.
Link access protocol (hereinafter referred to as LAPD) on the D channel terminating layer 2 on 3.24 25, 26
．． 27 and ISDN basic access subscriber line 22
, 23. A demultiplexing circuit 28 that multiplexes and demultiplexes logical links on 24, a failure detection device 29 connected to the multiplexed logical links and transmission paths of the demultiplexing circuit 28, and a LAPD.
25, 26, 27 and the fault detection device 29 and control device (
It includes a microprocessor bus 31 that connects to a host device 33 via a transmission path 32 and a microprocessor bus 31 that connects a
is connected to.

The failure detection device 29 of the I SDN subscriber accommodation device 21,
When a failure occurring in the transmission line 32 or the host device 33 is detected, the CPU 3
0 recognizes that a failure has occurred.

The CPU 30 connects to the LA via a microprocessor bus 31.
By controlling the PDs 25, 26, and 27 and de-synchronizing the ISDN basic access subscriber lines 22, 23, and 24, a failure was indicated to the terminal.

[Problem to be solved by the invention]

In the conventional flow control method described above, when the CPU 30 recognizes a failure in the transmission line 32 or the host device 33, the CPU 30 transmits the data to the LAPD 25, 26.2 via the microprocessor bus 31.
7 and ISDN Basic Access Subscriber Line 2
By removing the synchronization of 2, 23, and 24, a failure was indicated to the terminal, so the occurrence of a failure in the transmission line 32 would cause the entire I
SDN basic access subscriber line 22, 23゜24
In a protocol such as a link access protocol that allows multiplexing of a plurality of logical links per subscriber line, there is a problem in that the scope of failure is too large.

An object of the present invention is to provide a flow control method that minimizes the possibility that all logical links become unavailable at the same time and can reduce the range in which failures spread.

[Means to solve the problem]

The flow control method of the present invention is applied to an rS installed on the network side that accommodates a plurality of ISDN basic access subscriber lines.
In a flow control system for a DN subscriber accommodation device, a demultiplexing circuit demultiplexes a link access protocol on a D channel terminating layer 2 on the subscriber line and a logical link on the subscriber line in units of service access point identifiers. a failure detection circuit that detects a data transfer failure in units of service access point identifiers; a map of data link connection identifiers organized in units of service access point identifiers; and a failure detection circuit that detects data transfer failures in units of service access point identifiers; Equipped with multiple transmission lines for relaying to
The fault detection circuit detects a fault in the transmission path or a fault in a higher-level device and sends a fault notification signal to the control device, and the control device that receives the fault notification detects a terminal on the logical link where the transmission path fault is occurring. When an information frame containing transmission information is detected, the terminal is notified that the network side is busy by transmitting a receive not ready frame indicating that reception is not possible, and upon recovery from a failure, the information frame from the terminal is detected. Then, by transmitting a receive ready frame indicating that the frame can be received, the terminal is notified of the network side's cancellation of the busy state.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

The ISDN subscriber accommodation device 1 accommodates a plurality of ISDN basic access subscriber lines 2, 3.4, and
Layer 2 on N Basic Access subscriber line 2, 3.4
The LAPD 5, 6.7 terminating the ISDN basic access subscriber line 2, 3.7 and the logical link on the ISDN basic access subscriber line 2, 3. Link and 5AP
A demultiplexing circuit 8 that multiplexes and demultiplexes into two logical links with the I=16 (for Dch packet) link, and a demultiplexing circuit 8
failure detection devices 9 and 10 connected to two multiplexed logical links and transmission lines, and LAPD 25.26.27
and failure detection devices 9 and 1o, CPU II, and SAP
It includes a microprocessor bus 13 that connects a map 12 of data link connection identifiers (hereinafter referred to as DLCI) organized in I units, and transmission lines 14 and 15.
It is connected to host devices 16 and 17 via. Also, C
The PU 9 has logical link information of all subscriber lines for each type of SAP I as a DLCI map 10.

The upper device 16 has a connected logical link of SAP I
Since it is a Dch signal regarding =O, CCITT Recommendation Q, 931, which is an ISDN layer 3 protocol, is terminated. The host device 17 has 5 AP connected logical links.
Since it is a Dch packet regarding r=16, CCIT
T Recommendation

25 Layer 3 is terminated.

Next, the operation will be explained.

When the failure detection circuit 9 of the ISDN subscriber accommodation device 1 detects a failure in the transmission line 14 or a failure in the host device 16 for sending data grouped in units of 5 API = O, the CPU II detects this failure by Based on the logical link information of map 12 of DLCI of 5 API=O, the game busy mode is set for the logical link of SAP I=O of LAPD 5 and 6.7. As a result, for information (hereinafter referred to as ■) frames as data sent from terminals using the logical link identified by SAP I=O on all subscriber lines,
By transmitting a Receive Not Ready (hereinafter referred to as RNR) frame indicating that data cannot be received, the terminal is notified that data cannot be received. Similarly, 5API
= Transmission line 1 for sending data grouped into 16 units
5 or the host device 17 is detected by the fault detection circuit 10, the CPU 1 recognizes this fault via the processor bus 8, and the D of SAP I = 16 is detected.
LAPD5 based on the logical link information of LCr map 10
, 6.7, set the game busy mode for the 5API-16 logical link. As a result, 5A on all subscriber lines
For the frame as data sent from the terminal using the logical link identified by PI=16,
By transmitting an RNR frame, the terminal is notified that data cannot be received. Also, SAP
Transmission path 1 for sending data grouped in I=O units
4 or the host device 16 is detected by the fault detection circuit 9.
When the failure detection circuit 10 detects a failure in the transmission path 15 or the host device 17 for sending data grouped into 5AP116 units, the CPU II recognizes the failure via the processor bus 13, and the 5API= Based on the logical link information of DLCI map 12 of 0 and DLCI map 12 of 5API=16, LAPD5,6.7
Logical link of SAP I = O and SAP I =
Game busy mode is set for 16 logical links. As a result, SAP I = O and SA on all subscriber lines
Using the logical link identified by P I-16, for I frames as data sent from the terminal, notify the terminal that data cannot be received by transmitting an RNR frame. .

On the other hand, at the time of recovery, the CPU II recognizes the failure recovery from the failure detection circuits 9 and 10 via the processor bus 13, and the SA
Based on the logical link information of DLCI map 12 of P I
Set the game busy mode release for the logical link of SAP I unit of APD5, 6.7. As a result, 5AP
For one frame of data sent from a terminal using a logical link identified by I'''C, RR
By transmitting a frame, the terminal is notified that it is now ready to receive data.

〔Effect of the invention〕

As described above, the present invention provides an ISDN basic access subscriber line installed on the network side that accommodates a plurality
The SDN subscriber accommodation device includes a link access protocol on the D channel that terminates layer 2 on the subscriber line, a demultiplexing circuit that multiplexes and demultiplexes logical links on the subscriber line in units of service access point identifiers, and a service access point identifier. By providing a fault detection circuit that detects data transfer faults in each unit and a map of data link/connection identifiers organized in service access point identifier units, processing when a fault occurs is performed for each service access point identifier. This has the effect of minimizing the possibility that logical links become unusable at the same time, and reducing the range in which failures spread.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional flow control system. 1...I SDN subscriber accommodation device, 2,3.4
・・・・・・I SDN basic access subscriber line,
5゜6.7... Link access protocol (LAPD) on D channel, 8... Demultiplexing circuit, 9.10... Fault detection device, 11...・・・
・Control unit (CPU), 12... Data link connection identifier (DLCI) map, 13.
...Microprocessor bus, 14.15...
...Transmission line, 16°17... Upper device.

Claims (1)

[Claims] In a flow control system of an ISDN subscriber accommodating device provided on the network side that accommodates a plurality of ISDN basic access subscriber lines, a D that terminates layer 2 on the subscriber line
a demultiplexing circuit that demultiplexes a link access protocol on a channel, a logical link on the subscriber line for each service access point identifier, and a failure detection circuit that detects a data transfer failure for each service access point identifier;
A map of data link/connection identifiers organized in units of service access point identifiers, a plurality of transmission paths for relaying data to higher-level devices in units of service access point identifiers, and controls for controlling each of the above-mentioned devices and circuits. The fault detection circuit detects a fault in the transmission path or a fault in a higher-level device and sends a fault notification signal to the control device, and the control device that receives the fault notification detects a fault in the transmission path. When an information frame containing transmission information from a terminal is detected on a logical link, the terminal is notified that the network is busy by transmitting a receive not ready frame indicating that reception is not possible. A flow control system characterized in that when an information frame is detected, a receive ready frame indicating that the frame can be received is sent to the terminal to notify the terminal that the network side has released the busy line.