JP2877082B2 - Packet drop prevention method by burst alarm in SDCC communication - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to network management of a plurality of repeaters installed on the same line domain in an optical synchronous trunk transmission system, and more particularly to a method for preventing packet loss using an SDCC for network management.

[0002]

2. Description of the Related Art In an optical synchronous trunk transmission system, LA for communication management of a network element NE is used.
N or the SDCC for network management in the header of the transmitted frame is used.
The use of SDCC communication using 3 bytes of 1 to D3 is L
It is said that it is advantageous in terms of security and cost as compared with operation management using an AN, and is used not only for inter-station communication management but also for intra-station communication management between NEs.

FIG. 1 shows a typical N using SDCC communication.
3 shows an E management network. Generally, a plurality of relay devices 2-1 to 2-n are installed on a line domain between communication devices (terminal stations, nodes) 1-1 and 1-2 on the network.

[0004] In a network system in which each NE is managed by the upper operating system 3 of the communication device 1-1 using SDCC communication, a communication management packet sent from each NE is:
It will pass on the same SDCC.

For example, as shown in FIG. 1, a relay apparatus 2-n-1 on the same line domain transfers its own packet 4-n-1 between packets 4-n from the relay apparatus 2-n. The packet 4 is inserted into the SDCC as shown in FIG.
Send -a. Therefore, when a plurality of relay devices are installed on the same line domain, the load on the SDCC due to the simultaneous transmission of automatic report packets (burst alarm) increases depending on the type of the fault A. As a result, as shown in FIG. 4, packet discard occurs due to packet collision in the SDCC portion.

[0006]

In the prior art, when a burst-like communication management packet is generated simultaneously from a plurality of relay devices on the same line domain due to a failure or the like, the load of the network management SDCC is temporarily reduced. , Resulting in packet collisions and packet discards. This is due to the fact that control of packet transmission in anticipation of the load on the SDCC is not performed inside the relay device.

An object of the present invention is to provide a method for preventing packet loss due to a burst alarm in SDCC communication for preventing packet collision and discard for bursty packets generated simultaneously from a plurality of relay devices installed in the same line domain. It is to provide.

[0008]

According to the present invention, there is provided a method for preventing packet loss due to a burst alarm in SDCC communication, comprising the steps of: connecting a plurality of repeaters on the same line domain between node nodes of an optical backbone transmission system; Each of the devices uses a network management SDCC in the header of a frame transmitted by a higher-level operating system located in a node to prevent packet loss due to a burst alarm in a network system operated and managed. Storing a packet transmitted by the burst alarm in a buffer memory provided in the relay device; and counting a fixed time by a timer when multiplexing the packets in the buffer memory to the SDCC. And inside each By providing a predetermined time packets generated sent from the device to disperse the load on the SDCC by the simultaneous packet from the plurality relay device it is transmitted, and wherein reducing the dropping of packets.

Further, the step of counting the fixed time by a timer is such that when the time required to pass through one relay device is t, the maximum number n of relay devices in one line domain is t, It is characterized by having a step of t × n.

[0010]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an example of the configuration of a management network including a relay device having the function of the present invention. The communication devices 1-1 and 1-2 each include a host operating system 3 having a network operation management function. , Relay device 2
-1 to 2-n. FIG. 2 is a block diagram showing an embodiment of the present invention included in the relay apparatus. The alarm controller 5 generates a packet, the memory buffer 6 temporarily stores the generated transmission packet, and controls the transmission time. For this purpose, the system comprises a timer 7 for counting a certain time, an overhead separating section 8 for separating a destination signal from a main signal, and a multiplexing section 9 for multiplexing a destination signal to a main signal. As shown in FIG. 2, the packet loss prevention method according to the present invention employs a plurality of relay devices (2-1 to 2-n in FIG. 1) installed in the same line domain.
This is realized by giving a certain time difference when transmitting a packet. More specifically, in the relay device 2-1 to 2 -n, a transmission packet issued from the alarm controller 5 that generates a packet is stored in a memory buffer 6, a certain time is counted by a timer 7, and bursts in SDCC communication are performed. Prevent packet loss due to alarms.

Next, the operation of one embodiment of the present invention will be described.
This will be described with reference to FIG. FIG. 3 is a flowchart of one embodiment.

The packet generated by the relay device is sent to the host operating system 3. In the management network system using the SDCC, packets generated in the relay device 2-n are sequentially transferred to the relay device via the relay device 2-n-1 and transmitted to the higher-level operating system 3 of the communication device 1-1. To reach.

However, when packets are simultaneously transmitted from each relay device to the SDCC, a timer is set in anticipation of the time when a previously generated packet reaches the communication device at the end of the line domain, and the set fixed time is set. By clearing and sending the next packet, SDC
The load on C is reduced, and packet loss due to packet collision is avoided.

Next, the packet passing through the relay device and the packet generated by the relay device will be described.

As shown in FIG. 2, the packet passing through the repeater flows on the SDCC and is separated from the main signal by the overhead separator 8. If the signal is addressed to the repeater, the control unit 5 It is taken in. If the destination is further than the line, the multiplexed signal is multiplexed by the multiplexing unit 9 to the main signal and transferred to the next-stage relay device or node.

As shown in FIG. 2, the packet generated by the relay device is multiplexed with the main signal in the multiplexed portion as it is, but is not multiplexed with the packet generation, but is temporarily stored in a memory buffer and then stored. The time is counted by the time timer 7 and sent to the multiplexing unit 9.

As described above, the probability of collision between the packet generated by the relay device and the packet generated and passed in the preceding stage is reduced. As a specific embodiment, the number of relay devices is determined to be a maximum of 30 (the maximum number of n) in one line domain. As an example, if the number of relay devices is 30
When the time required for the operation management packet to pass through one relay device is 86 msec, the counter is adjusted to 2.5 sec.

[0019]

The effect of the present invention is to prevent packet loss by lowering the packet collision probability. As a result, highly reliable communication can be secured.

The reason is that a certain time interval is provided between sending packets generated by the relay device. Since the next-stage relay device also sends packets at intervals in the same manner, no collision occurs in the last-stage relay device.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a management network including a relay device having a function of the present invention.

FIG. 2 is a block diagram showing one embodiment of the present invention included in the relay device of FIG. 1;

FIG. 3 is a flowchart showing the operation of one embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of insertion and collision by continuous packets in the relay device.

[Explanation of symbols]

 1-1, 1-2 Communication device (terminal station, node) 2-1 to 2-n Relay device 3 Upper operating system (0S) 4-1 to 4-n Packet to upper 0S 5 Control unit 6 Memory buffer unit 7 Timer section 8 Overhead separation section 9 Multiplex section

Claims (2)

(57) [Claims] 1. A plurality of relay devices are connected on the same line domain between nodes of an optical synchronous trunk transmission device,
Each of the relay devices uses an SDCC for network management in a header of a frame transmitted by a higher-level operating system located in a node,
In a method for preventing packet loss due to a burst alarm in a network system under operation management, a step of storing a packet transmitted by the burst alarm in a buffer memory installed in the relay device; A step of counting a fixed time by a timer when multiple transmissions are performed, and by providing a fixed time interval between packets generated and transmitted from each relay device, packets can be simultaneously transmitted from a plurality of relay devices. A method for preventing packet loss due to a burst alarm in SDCC communication, wherein the load on the SDCC due to the above is distributed and packet discarding is reduced. 2. The method according to claim 1, wherein the step of counting the predetermined time by a timer includes: when the maximum number of relay devices in one line domain is n; and when the time required to pass through one relay device is t, the predetermined time is defined as t. 2. The method as claimed in claim 1, further comprising the step of: t * n.