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Configuration Guide - Device Management

CloudEngine 8800, 7800, 6800, and 5800 V200R005C10

This document describes the configurations of Device Management, including device status query, hardware management, Information Center Configuration, NTP, Synchronous Ethernet Configuration, Fault Management Configuration, Energy-Saving Management Configuration, Performance Management Configuration, Maintenance Assistant Configuration, and OPS Configuration.
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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Typical Synchronous Ethernet Networking

Typical Synchronous Ethernet Networking

Chain Topology

In Figure 5-5, Device1, Device2, Device3, and Device4 are connected in a chain topology using Ethernet links. Device2 functions as the master clock of the network and is connected to an external clock, while other devices trace the clock of Device2.

Device1, Device2, Device3, and Device4 synchronize the time with the external clock in the following method:

  1. Device2 extracts clock information from the bit stream input by the external clock as its local clock, stores the clock information in the Ethernet bit stream, and transmits the bit stream to Device1 and Device3.
  2. Device1 extracts clock information from the Ethernet bit stream received by its E interface as its local clock.
  3. Device3 extracts clock information from the Ethernet bit stream received by its W interface as its local clock, stores the clock information in the Ethernet bit stream, and transmits the bit stream to Device4.
  4. Device4 extracts clock information from the Ethernet bit stream received by its W interface as its local clock.
Figure 5-5 Chain topology

The lower-level device traces the clock information stored by the upper-level device in the Ethernet bit stream regardless of which mode the upper-level device works in. Therefore, when the clock performance of Device2 degrades, the clock performance of the entire network degrades.

If the clock information reaches the end device through long-distance transmission or several transfers, the quality of clock signals received by the end device will degrade. To ensure the quality, two reference clocks can be configured on the network. In this case, some devices trace one reference clock, and other devices trace the other reference clock. The two reference clocks need to be kept synchronous and have the same SSM quality level.

Ring Topology

In Figure 5-6, Device1, Device2, Device3, Device4, Device5, and Device6 are connected in a ring topology using Ethernet links. Device1 functions as the master clock of the network and is connected to an external clock, while other devices trace the clock of Device1.

Clock synchronization of other devices in a ring topology is the same as that in a chain topology except that other devices can extract clock information from the Ethernet bit streams received by two line interfaces. Considering the impact of the number of transfers and transmission distance on clock signals, other devices extract the clock information through the interface with the shortest path and least number of transfers. When multiple interfaces that obtain clock signals have the same path length and number of transfers, a device uses the clock source selection algorithm to select an interface to trace clock signals. For example, Device5 traces the clock through its W interface, and Device4 traces the clock through its E interface.

Figure 5-6 Ring topology

Hybrid Topology

In Figure 5-7, Device1, Device2, Device3, and Device4 are connected in a ring topology using Ethernet links, while Device4 and Device5 are connected in a chain topology using an Ethernet link. Device5 functions as the master clock of the network and is connected to an external clock, while other devices trace the clock of Device5.

Clock synchronization of other devices in a hybrid topology is the same as that in a chain or ring topology. Device5 extracts clock information from the bit stream input by the external clock as its local clock, stores the clock information in the Ethernet bit stream, and transmits the bit stream to downstream devices.

Figure 5-7 Hybrid topology
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Updated: 2019-04-20

Document ID: EDOC1100075362

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