JP3175953B2 - Communications system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trunk network composed of a plurality of stations, and a plurality of branch networks connected to the stations of the trunk network, such as a private communication system having a similar frame structure. Communication system.

[0002]

2. Description of the Related Art In recent years, 100M (mega) bps, 400
With the emergence of branch networks (branch LANs) as high-speed local networks of Mbps, services of broadband terminals such as moving images have become possible using LANs (local area networks).

However, as the number of connected terminals and the number of LANs increase, the above 100 Mbps, 400 Mbps
The transmission speed of bps is becoming insufficient. For example, an image terminal such as an HDTV needs a transmission band of 100 Mbps or more even if a band compression technique is used. Therefore, it has become necessary to construct a trunk network (trunk LAN) as a private communication system capable of transmitting a large capacity exceeding G (giga) bps. at the same time,
It is also necessary to consider technologies for quickly detecting and recovering from network failures, as well as enhancing maintenance and management functions.

As a result, if a failure occurs in the transmission line of the trunk LAN having a transmission capacity of several Gbps, the branch LAN multiplexed on the transmission line will be damaged.
Techniques are needed to quickly restore transmission path failures and increase reliability.

[0005]

As described above, the number G
If a failure occurs in a transmission line of a trunk network having a transmission capacity of bps, it will cause damage to the branch line network multiplexed on the transmission line. Therefore, a technology for quickly restoring the transmission line failure and improving reliability is necessary. Become.

The present invention communicates a fault between stations in a trunk network to a branch network connected to the station,
To provide a communication system capable of optimally controlling connection of a transmission line by performing restoration of a transmission line failure by automatic detour, dynamically reconfiguring a network, and further improving reliability, flexibility and economy. With the goal.

[0007]

Means for Solving the Problems A communication system of the present invention is composed of a trunk network to which the branch network as a loop or ring-shaped branch network is connected through a station, said plurality of branch networks before
Are multiplexed on a transmission path the serial trunk network, these Ne
Networks with similar structures between the networks
In a communication system is fed perform communication, the trunk Ne
And notification transmission path on the disabled Gaiken unloading of Ttowaku put to a particular channel in the frame transferred between the respective stations, those
Each station automatically cuts off the detour while disconnecting the faulty section.
An automatic distribution function is provided.

[0008]

The present invention comprises a loop or ring-shaped branch network and a trunk network to which the branch network is connected via a station. The plurality of branch networks are multiplexed on a transmission line, and the transmission line is In the case where communication is performed by a transmitted frame, detection and notification of a failure in the transmission path are transferred between stations using a specific channel in the frame, and each station automatically disconnects a failure section. It was made.

[0009]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration example of a communication system according to the present invention. That is, a number of branch LANs (branch networks) 11 and 12 are trunk LANs (trunk network).
The lines are connected to 15 nodes A and B. In addition, trunk line LA
A node C is also provided at N15. Branch line LAN1
One frame is multiplexed in the node A of the trunk LAN 15 and transferred to another node B via the transmission line 16 of the high-speed trunk LAN 15. The frame arriving at the node B is passed to the branch LAN 12. The branch line LANs 11 and 12
Are also provided with nodes E, F, G, and H, respectively.

Each of the nodes A,... Of the trunk LAN 15 is provided with a transmission path switch (SW1, SW2) as shown in FIGS. 2 (a) and 2 (b). By transmitting a control signal (K2) for switching, the transmission path 16 is switched.
The frames of the trunk LAN 15 and the branch LANs 11 and 12 are:
It has a frame structure as shown in FIG.

For example, when a branch LAN (155.52 Mbps) 11 (12) having a transmission capacity of n = 1 is multiplexed to the trunk LAN 15, n = 8 or n = 8.
16 trunk LANs (1.24416 Gbps, 2.48
832 Gbps) 15 is used. The frame is SO
H, POH, and a container unit.

When the present frame is used in the branch LAN 11 (12), the payload portion as shown in FIG.
Data such as a frame header, a connection control packet section, a circuit switching data section, and a packet switching data section are mapped. The node E of the branch LAN 11 (12) is connected to the POH.
The status monitoring information (error monitor) of the terminal (not shown) connected to (H) is mapped, and the transmission line 11a (each of the nodes E and F (G, H) of the branch LAN 11 (12) is mapped to the SOH. 12a) Status monitoring information (error monitor)
Are mapped, and control information (K2) for controlling the transmission path changeover switches (SW1, SW2) at the nodes E and F (G, H) is mapped.

When this frame is used for the trunk LAN 15, a large number of branch LANs 11,
Twelve payload data are mapped, and the POH has status monitoring information (error monitor) of each of the branch LANs 11 and 12 connected to the nodes A and C of the trunk LAN 15;
The SOH includes a transmission line 16 between each node of the trunk LAN 15.
State monitoring information (error monitor), control information (K2) for controlling the transmission path changeover switches (SW1, SW2) in the nodes A and C, and the like are mapped.

FIG. 5 shows the meaning of each channel. That is, K2 is a transmission path state monitoring / alarm transfer, A1, A2
Is frame synchronization, B1 and B2 are error monitoring, D1 to D
3, D4 to D12 are data links, E1 and E2 are maintenance channels, C1 is a multiplex number not allowed, K1 and K2
Is a system switch control, F1 is a user channel, H1, H2, and H3 are different speed AU synchronizations, stuff bytes, B3 is an error monitor, J1 is a maintenance channel, and F2 is a user channel. I have.

The channels B1 to audit <br/> view of the transmission path error trunk LAN15 for error monitoring of the node in the overhead as shown in FIG. 5, B2, changeover switch channels K1 of the transmission path 16 of the main line LAN15 , K2, and branch lines LAN 11 and 12 can use similar channels. Further, there is a channel B3 for monitoring a transmission line error in a so-called POH.

That is, information on the error rate of the trunk LAN 15 and the branch LANs 11 and 12 is inserted into these B1, B2 and B3 channels. Each of these channels can be monitored at the time of multiplexing. This channel B1,
Since B2 and B3 are detected and inserted at each node, it is set so that transmission of alarm information (K2) is transferred when there is an error.

However, in order to prevent the error rate from intermittently changing, it is necessary to change the K2 channel so that the threshold of the error rate has a certain width. Therefore, the change of the K2 channel has a period of about several msec. However, the node that detects K2 automatically causes the network to autonomously bypass the faulty section, and the trunk LAN 15
Is performed.

For example, as shown in FIG. 2A, when a failure occurs between node A and node B, as shown in FIG. Data is transmitted to the node B.

[0020]

As described above in detail, according to the present invention, a fault between stations in a trunk network is notified to a branch network connected to the station, and a transmission path fault is recovered by automatic detour. Accordingly, it is possible to provide a communication system capable of optimally controlling connection of a transmission path, dynamically reconfiguring a network, and improving reliability, flexibility, and economy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a communication system according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a transmission path changeover switch provided in each node of FIG. 1;

FIG. 3 is a diagram showing a frame structure in the communication system of FIG. 1;

FIG. 4 is a diagram showing a mapping example of a payload portion of the frame in FIG. 2;

FIG. 5 is a diagram showing the meaning of each channel in the payload section of FIG. 3;

[Explanation of symbols]

11, 12 ... branch LAN (branch network, 15 ... trunk LAN (trunk network), 16 ... transmission line, A,
B, C, E, F, G, H: nodes (stations).

Claims (1)

(57) [Claims] 1. A branch network comprising a loop or ring-shaped branch network and a trunk network to which the branch network is connected via a station, wherein the plurality of branch networks are multiplexed on a transmission line of the trunk network. Up frame with similar structure between
In a communication system for performing communication by transmitting the serial transmission line, put a notice to the transmission line on the disabled Gaiken unloading of the trunk network to a particular channel in the frame transferred between the respective stations, in the stations Automatically with disconnection of obstacle section
A communication system, further comprising an automatic distribution function for forming a detour .