JPH0265344A - Packet synchronizing control system - Google Patents

Abstract

PURPOSE:To load packet synchronization without lowering the efficiency of a transmission path by changing a deciding condition for synchronization establishment and synchronization step-out in correspondence to the measured value of an idle packet rate. CONSTITUTION:A sent packet is decided by an idle packet deciding circuit 11 and an idle packet pulse is outputted to a counter 12. The output of the counter 12 is measured as an idle packet rate (an idle packet arrival number) (k). When an address setter 14 designates the addresses of a k-m.k-n table 15 in correspondence to the idle packet rate (k), contents (m) or (n) of the table are inputted through a register 16 or 17 to a packet synchronizing part 2. When a frame pattern inserted into an idle packet is detected continuously by the (m)-times in the packet synchronizing part 2, such a condition is decided as the synchronization establishment. When the packet having the frame pattern is not detected in the packet synchronizing part 2 even when that the (n)-packet is obtained, such a condition is decided as the synchronization step-out.

Description

[Detailed Description of the Invention] Summary Regarding a packet synchronization control method, it is possible to perform packet synchronization during packet transmission without reducing the efficiency of the transmission path, and to reliably determine synchronization establishment and synchronization loss. The purpose of this method is to provide a packet synchronization control method that enables synchronization by inserting a predetermined frame pattern into an empty packet on the transmitting side, and establishing synchronization by detecting the frame pattern on the receiving side. In the packet synchronization control method, the receiving side includes an empty packet rate measuring means for measuring the empty packet rate of the line, and a synchronization judgment condition setting means for changing the judgment condition for synchronization establishment and synchronization loss according to the measured value of the empty packet rate. is established, and when the receiving side detects a frame pattern inserted into empty packets m times (m is a natural number) consecutively, it is determined that synchronization has been established, and even if the frame pattern waits for n packets (n is a natural number), The configuration is configured to determine that the synchronization is out of synchronization when it is not detected.

Industrial applications The present invention relates to a packet synchronization control method.

It is thought that future communication services will be centered on multimedia communication services that combine multiple types of media, with services for each media becoming more diverse and sophisticated. It is desirable that communication networks provide these services economically and improve user convenience. Therefore, it is necessary to integrate various individual services and provide communication services to users through a unified interface.

Service integration refers to the ability of digital communication networks to provide various single or combined services on a call-by-call basis through standardized user-network interfaces. CCITT defines a comprehensive service network equipped with the function of making digital connections between users and network interfaces as a 5DN (integrated service digital network).

In such a wideband I5DN, all information such as voice, images, data, etc. is handled one-dimensionally and transmitted as digital signals. By sending packets of information only when the information is generated, the efficiency of line usage increases, and
All speeds from low to high can be handled centrally.

By the way, packet synchronization is a problem when transmitting a large amount of these short packets of a fixed length. Packet synchronization is the process of finding the beginning and end of a packet, as well as the dividing point between a part of the header and the information part. Without packet synchronization, the transmitted information cannot be retrieved correctly, so it improves the efficiency of the transmission path. There is a need for a packet synchronization control method that can reliably maintain packet synchronization without any loss of packet synchronization.

BACKGROUND OF THE INVENTION Conventional packet synchronization control methods generally include a method in which a transmitting side sends out a predetermined frame pattern at certain intervals, and a receiving side synchronizes based on this frame pattern. However, with this method, it is necessary to prepare packets for inserting frame patterns at certain intervals, which causes a problem that the efficiency of the transmission path decreases. Therefore, as a method for performing packet synchronization without reducing the efficiency of the transmission path, a method has been proposed in which a frame pattern is inserted into an empty packet (a packet that does not contain information).

Problems to be Solved by the Invention However, according to this method, when the empty packet rate (ratio of empty packets included in all transmitted packets) decreases, the rate at which frame patterns arrive at the receiving side decreases, making it difficult to establish synchronization and synchronization. There was a problem in that it was difficult to judge whether the disc was out of alignment or not.

The present invention has been made in view of the above points, and its purpose is to enable packet synchronization in packet transmission without reducing the efficiency of the transmission path, and to prevent synchronization establishment and synchronization loss. It is an object of the present invention to provide a packet synchronization control method that can reliably make a determination.

Means for Solving the Problems In a packet transmission system using packets of a fixed length, a predetermined frame pattern is inserted into an empty packet on the transmitting side. On the receiving side, as shown in the principle diagram of FIG. 1, in addition to the conventionally known reception termination circuit 1, packet synchronization section 2, and data output control section 3, there is an empty packet rate measurement unit that measures the empty packet rate of the line. A means 4 and a synchronization determination condition setting means 5 are provided for changing the conditions for determining synchronization establishment and synchronization loss according to the measured value k of the empty packet rate.

Then, when the receiving side detects a frame pattern inserted into an empty packet m times (m is a natural number) consecutively, it is determined that synchronization has been established, and even if the frame pattern waits for n packets (n is a natural number), it is detected. When the synchronization is not performed, it is determined that the synchronization is out of synchronization.

The relationship between the empty packet rate, m, and k and n is calculated in advance using a statistical method or the like, and is written in the memory within the receiving device.

Operation In the present invention, as described above, the empty packet rate is measured on the receiving side, and the packet synchronization unit 2 is controlled according to the empty packet rate. In other words, the empty packet rate measuring means 4 measures the empty packet rate (the number of empty buckets/IT arrivals) k per unit time, and the frame pattern is inserted into the empty packets m times in a row according to the measured value. When this frame pattern is detected, the packet synchronizer 2 determines that synchronization has been established, and when this frame pattern is not detected even after waiting for n packets, the packet synchronizer 2 determines that synchronization has been lost.

Since the m and n values are changed according to the empty packet rate in this way, even if the empty packet (EE) becomes smaller and the interval between frame pattern arrivals becomes longer, the receiving side will not be able to establish or lose synchronization. Judgments can be made reliably.

Example Embodiments of the present invention will be described in detail below based on the drawings.

On the transmitting side, a frame pattern insertion circuit inserts a fixed format frame pattern into an empty packet. Furthermore, so that the receiving side can determine whether an empty packet is an empty packet, for example, a packet empty flag is set on the transmitting side for an empty packet.

FIG. 2 shows a block diagram of an embodiment on the receiving side. First, the signal from the line is subjected to processing such as serial/parallel conversion in the reception termination circuit 1. An empty packet determination circuit 11 determines the percentage of empty packets among the sent packets by detecting a flag set for empty packets, and outputs an empty packet pulse to a counter 12. The counter 12 is configured to be reset by a timer 13 at a predetermined time. Since the length of the packet is constant, the number of packets received per unit time is the same. Therefore, the output of the counter 12 is the empty packet rate (
The number of empty packets arriving) is measured as k, and is input to the address setter 14.

The address setter 14 sets the address of the -n table 15 in -m-. In this case, the -m・k−n table 15 is created in advance using a statistical method.
The relationship between and n is calculated and written into the ROM.

The address setter 14 -m according to the empty packet rate k
- When the address of the -n table 15 is specified, the contents of the table or n corresponding to this address is set to the register 16.
Or it is input to the packet synchronization unit 2 via 17. k-
The relationship of m is used to determine the establishment of synchronization, and the packet synchronization unit 2 detects the frame pattern included in the packet,
When a frame pattern inserted into empty packets is detected m times in a row, it is determined that synchronization has been established. Also, k
The relationship -n is used to determine out-of-synchronization, and when the packet synchronization unit 2 does not detect a packet containing a frame pattern even after n packets have been received in a synchronization established state, it is determined that out-of-synchronization has occurred. The packet synchronizer 2 synchronizes the data output controller 3 and transmits the synchronization signal to the next stage device in parallel with the received data.

Effects of the Invention Since the packet synchronization control method of the present invention is configured as described above, frame patterns can be transmitted using only empty packets, so packet synchronization can be performed without reducing the efficiency of the transmission path, and synchronization can be performed. This has the effect that establishment and out-of-synchronization can be determined reliably.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram of the present invention on the receiving side, and FIG. 2 is a block diagram of an embodiment of the present invention on the receiving side. DESCRIPTION OF SYMBOLS 1... Reception termination circuit, 2... Packet synchronization unit, 3... Data output control unit, 4... Empty packet rate measuring means, 5... Synchronization judgment condition setting means, 11... Empty Packet judgment circuit, 12...Counter, 13...Timer, 14...Address setter, 15.km.kn table, 16.17..Register.

Claims (1)

[Claims] In a packet synchronization control method using packets of a fixed length, in which synchronization is established by inserting a predetermined frame pattern into an empty packet on the transmitting side and detecting the frame pattern on the receiving side, the receiving side , an empty packet rate measuring means (4) for measuring the empty packet rate of the line, and a synchronization judgment condition setting means (5) for changing the judgment condition for synchronization establishment and synchronization loss according to the measured value of the empty packet rate. , When the receiving side detects a frame pattern inserted into empty packets m times (m is a natural number) consecutively, it is determined that synchronization has been established, and the frame pattern is not detected even after waiting for n packets (n is a natural number). A packet synchronization control method that is characterized in that it sometimes determines that synchronization has been lost.