Huawei CX600-8 Hardware Description page 119

HUAWEI CX600-8/16/X3/X8/X16 Metro Service Platform
Hardware Description
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System Clock Unit
As the system clock unit, the SRU provides accurate and reliable SDH clock signals for LPUs.
The SRU can provide three-channel 2.048 MHz synchronous clock signals for the downstream
devices, or receive 2.048 MHz or 2.048 Mbit/s external reference clock signals.
To support IEEE 1588v2, that is, the Precision Time Protocol (PTP), the SDH clock interface
can input time information in multiple formats by selecting specific software.
System Maintenance Unit
As the system maintenance unit, the SRU collects system monitoring information to test system
units locally or remotely, or implement in-service upgrading of system units.
The SRU periodically collects information about the operation of system units through the
MonitorBus. The SRU then generates related control information based on the collected
information, for example, the detection of board installations and adjustments to fan speed.
Through the joint test action group (JTAG) bus, the SRU remotely or locally tests system units,
or performs in-service upgrading of system units.
Reliability
The main control modules, clock modules, and LAN switch modules on the SRU work in 1:1
hot backup mode, therefore improving system reliability.
The two SRUs work in 1:1 backup mode. Each SRU monitors the status of the other. If the
master SRU is faulty, the slave SRU automatically takes over as the master SRU.
4.5.2 Switch and Route Processing Unit A7
Switch and Route Processing Unit A7 is the 100G Switch and Route Processing Unit
Appearance
Figure 4-22
Issue 03 (2013-11-30)
Route calculation: All routing protocol packets are sent by the forwarding engine to the
SRU for processing. In addition, the SRU broadcasts and filters packets, and downloads
routing policies from the policy server.
Outband communication between boards: The LAN switch modules integrated on the SRU
provide outband communications between boards. In this manner, messages can be
controlled, maintained, and exchanged between the boards.
Device management and maintenance: Devices can be managed and maintained through
the management interfaces (serial interfaces) provided by the SRU.
Data configuration: The SRU stores configuration data, startup files, charging information,
upgrade software, and system logs.
Data storage: The SRU provides two interfaces for CF cards, which serve as mass storage
devices to store data files.
NOTE
shows appearance of the CX6D0SRUA770.
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