NOTE
The air filter of the USG9520 can be adjusted through bending, facilitating the maintenance within a
limited space at the rear of the chassis.
Placing a black sponge air filter at the air intake vent helps prevent dust from entering the system. You
are advised to remove and clean the air filter once every three months.
1.3.6 Control Plane
This section describes the functions and features of the control plane.
USG9520 uses the MPU to implement the functions of the control plane. The functions
include centralized control and management and data exchange. For details about the MPU,
see
. The functions of the MPU are described from the aspects of
system control and management, system maintenance, and reliability:
System Control and Management Unit
As the system control and management unit, the MPU provides the following functions on the
system control panel:
l
Route calculation: All routing protocol packets are sent by the forwarding engine to the
MPU for processing. In addition, the MPU broadcasts and filters packets, and downloads
routing policies from the policy server.
l
Outband communication between boards: The LAN switch modules integrated on the
MPU provide outband communications between boards. In this manner, communications
between the LPUs and SPUs are controlled and maintained, and messages can be
exchanged.
l
Device management and maintenance: Devices can be managed and maintained through
the management interfaces (serial interfaces) provided by the MPU.
l
Data configuration: The MPU stores configuration data, startup files, upgrade software,
and system logs.
l
Data storage: The MPU has one USB card, which serves as a mass storage device to
store data files.
System Maintenance Unit
As the system maintenance unit, the MPU collects monitored information to test system units
locally or remotely, or implements in-service upgrading of system units.
The MPU periodically collects information about the operation of system units through the
Monitorbus. The MPU generates related control information based on the collected
information, such as the detection of board installations and fan speed adjustments. Through
the joint test action group (JTAG) bus, the MPU 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 MPU work in 1:1
hot backup mode, improving system reliability.
The two MPUs work in 1:1 backup mode. Each MPU monitors the status of the other. If the
active MPU is faulty, the standby MPU automatically takes over as the active MPU.
HUAWEI USG9500 Series
Hardware Guide
1 Hardware Overview
Issue 03 (2017-12-15)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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