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ME60 V800R010C10SPC500 Feature Description - System Management 01

This is ME60 V800R010C10SPC500 Feature Description - System Management
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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).
Application Scenarios for 1588v2and G.8275.1

Application Scenarios for 1588v2and G.8275.1

Currently, 1588v2 is applicable to a link where all devices are 1588v2-capable, and a maximum of 30 hops are supported.

Because a master clock has multiple slave clocks, it is recommended to use the BITS or IP clock server as the master clock. It is not recommended to use any device as the master clock because the CPU of the device may be overloaded.

1588v2 Clock Synchronization in E2E Mode

Figure 14-17 Networking diagram of 1588v2 clock synchronization in E2E mode

As shown in Figure 14-17, clock servers and NodeBs exchange TOP-encapsulated 1588 messages over a QoS-enabled bearer network with the jitter being less than 20 ms.

Scenario description:

  • NodeBs only need frequency synchronization.

  • The bearer network does not support 1588v2 or frequency recovery in synchronous Ethernet mode.

Solution description:

  • The bearer network is connected to a wireless IP clock server and adopts 1588v2 clock synchronization and frequency recovery in E2E mode.

  • The clock server sends 1588v2 timing messages, which are transparently transmitted over the bearer network to NodeBs. Upon receiving the timing messages, NodeBs perform frequency recovery.

  • 1588v2 timing messages need to be transparently transmitted by priority over the bearer network; the E2E jitter on the bearer network must be less than 20 ms.

  • Advantage of the solution: Devices on the bearer network are not required to support 1588v2, and are therefore easily deployed.

  • Disadvantage of the solution: Only frequency synchronization rather than time synchronization is performed. In practice, an E2E jitter of less than 20 ms is not ensured.

1588v2 Clock Synchronization in Hop-by-Hop Mode

Figure 14-18 Networking diagram of 1588v2 clock synchronization in hop-by-hop mode

As shown in Figure 14-18, the clock source can send clock signals to NodeBs through the 1588v2 clock, WAN clock, synchronous Ethernet clock, or any combination of clocks.

Scenario description:

  • NodeBs only need frequency synchronization.

  • GE links on the bearer network support the 1588v2 clock rather than the synchronous Ethernet clock.

Solution description:

  • The Synchronous Digital Hierarchy (SDH) or synchronous Ethernet clock sends stratum 3 clock signals through physical links. On the GE links that do not support the synchronous Ethernet clock, stratum 3 clock signals are transmitted through 1588v2.

  • Advantage of the solution: The solution is simple and flexible.

  • Disadvantage of the solution: Only frequency synchronization rather than time synchronization is performed.

Bearer and Wireless Networks in the Same Clock Domain

Figure 14-19 Networking diagram of the bearer and wireless networks in the same clock domain

Scenario description:

  • NodeBs need to synchronize time with each other.

  • The bearer and wireless networks are in the same clock domain.

Solution description:

  • The core node supports GPS or BITS clock interfaces.

  • All nodes on the bearer network function as BC nodes, which support the link delay measurement mechanism to handle fast link switching.

  • Links or devices that do not support 1588v2 can be connected to devices with GPS or BITS clock interfaces to perform time synchronization.

  • Advantage of the solution: The time of all nodes is synchronous on the entire network.

  • Disadvantage of the solution: All nodes on the entire network must support 1588v2.

Bearer and Wireless Networks in Different Clock Domains

Figure 14-20 Networking diagram of the bearer and wireless networks in different clock domains

Scenario description:

  • NodeBs need to synchronize time with one another.

  • The bearer and wireless networks are in different time domains.

Solution description:

  • The GPS is used as a time source and is connected to the wireless IP clock server.

  • BCs are deployed in the middle of the bearer network to synchronize the time of the intermediate network.

  • TCs are deployed on both ends of the bearer network. TCs only correct the message transmission delay and send the time to NodeBs, but do not synchronize the time with the clock server.

  • Advantage of the solution: The implementation is simple because the bearer network does not need to synchronize with the clock server.

  • Disadvantage of the solution: Devices on both ends of the bearer network need to support 1588v2 in TCandBC mode.

G.8275.1 Per-Hop Clock Synchronization

Figure 14-21 G.8275.1 per-hop clock synchronization

Scenario description:

  • NodeBs need to synchronize time with one another.

  • The bearer and wireless networks are in the same clock domain.

Solution description:

  • Core nodes support GPS/BITS interfaces.

  • Network-wide time synchronization is achieved from the core node in T-BC mode. All T-BC nodes support path delay measurement to adapt to fast link switching.

  • Network-wide synchronization can be traced to two grand masters.

  • The advantage of the solution is that the network-wide time is synchronized to ensure the optimal tracing path.

  • The disadvantage of the solution is that all nodes on the network need to support 1588v2 and G.8275.1.

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Updated: 2019-01-04

Document ID: EDOC1100059466

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