Configuring G.8275.1
Usage Scenario
On the network shown in Figure 1, the BITS interface that functions as the T-GM obtains high-accuracy time information from a global positioning system (GPS), encapsulates the information into a G.8275.1 packet, and sends the packet to the bearer network. A bearer network device that functions as the T-BC transparently transmits the time information to all devices on the bearer network. BCs send high-accuracy time information carried in the G.8275.1 packet to wireless access devices, such as a NodeB and a radio network controller (RNC).
- Configuring a BITS Source As the T-GM
- You can configure a building integrated timing supply system (BITS) source as the telecom grandmaster (T-GM). The T-GM is connected to telecom boundary clocks (T-BCs) through Ethernet clock interfaces. The T-GM serves as the grandmaster clock to provide time signals to T-BCs on the transport network, allowing time synchronization between T-BCs and the T-GM.
- Configuring Clock Source Attributes for BMC Selection
- After BITS signal input is configured on multiple T-BCs, you can configure the clock source attributes of the T-BCs to allow them to participate in best master clock (BMC) selection. You can also configure the local clocks of T-BCs to participate in BMC selection. The BMC algorithm (BMCA) helps routers to dynamically select a master clock. The master clock provides time signals for the entire G.8275.1 network. T-BCs use G.8275.1 to achieve time synchronization with the grandmaster clock.
- Globally Configuring G.8275.1
- To ensure G.8275.1 for time synchronization, you need to globally enable G.8275.1 in the system view, set the device type to T-BC/T-TC, and configure basic information such as the domain value and virtual clock ID.
- (Optional) Configuring the Time Synchronization Alarm Function
- After the time synchronization alarm function is configured to monitor time synchronization status information, the alarm information will be reported to the NMS for further troubleshooting and maintenance.
- Configuring G.8275.1 on an Interface
- After enabling G.8275.1 in the system view, you need to enable G.8275.1 in the interface view.
- Configuring Time Attributes for G.8275.1 Packets
- T-BCs exchange Announce, Sync, and Delay or Pdelay packets to send time information and maintain G.8275.1 connections. You can set the interval at which a G.8275.1 interface sends Announce, Sync, and Delay or Pdelay packets and the maximum number of Announce packet timeouts. Using the default time attribute values is recommended.
- Configuring Encapsulation Modes for G.8275.1 Packets
- You can configure destination MAC addresses of packets according to the actual networking.
- Verifying the G.8275.1 Configuration
- After configuring the G.8275.1 function, verify the configuration.