Clock synchronizing method in bag-exchanging network and realizing apparatus tehrefor

Abstract

This invention discloses a method for synchronizing clocks in a packet exchange network including: the NE of a sending end sends data messages at a rate in terms of the necessary transmitted clocks and the NE of the receiving end receives data messages in terms of the rate to resume the local clock based on the frequency for receiving said data messages. This invention discloses a device for realizing clock synchronization in a packet exchange network composed of an operation module, an inverse control module and a frequency generation module connected orderly, in which, the operation module is connected with the FIFO used in sending and receiving and storing the packet exchange network data messages, besides, the device can be composed of a clock resuming module, a phase discriminating module and a frequency generating module.

Description

technical field [0001] The invention relates to the field of packet switching network technology, in particular to a clock synchronization method and implementation device in the packet switching network. Background technique [0002] In a packet-switched network, such as Ethernet, data is exchanged and transmitted in the form of packet forwarding. In the process of packet forwarding, the local clock is used to send data packets, see figure 1 As shown, a first-in-first-out memory (FIFO) in each network element utilizes a local clock to perform read operations. Therefore, all network elements in the packet-switching network work in an asynchronous mode, which makes it very difficult to transparently transfer the clock through the packet-switching network and realize synchronization at both ends of the packet-switching network. [0003] In order to solve the above problems, the prior art adopts the method of synchronizing the physical layer of the whole network to the packet...

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Problems solved by technology

[0006] 1) It is not compatible with the previous packet-switching network. Since the transmission clock of the existing packet-switching network line adopts the local clock, it needs to be updated and supported by all the devices in the whole network;

[0007]2) Since the packet switching network topology is generally a mesh structure, network-level clock tracking transmission methods such as clock looping need to be considered for network-wide synchronization, which is very complicated and difficult to implement Difficult and lacks stability

Each network element has multiple clocks to choose from. If the wrong choice is made, the clocks will track each other and the clock performance will be greatly degraded.

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