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EX9253 Chassis

 

Chassis Physical Specifications of an EX9253 Switch

The EX9253 switch chassis is a rigid sheet-metal structure that houses all components of the switch. EX9253 is available in two variants—with AC power supply and with DC power supply. Table 1 summarizes the physical specifications of the EX9253 switch chassis.

Table 1: Physical Specifications of the EX9253 Switch Chassis

Description

Weight

Width

Depth

Height

AC-powered chassis fully loaded with all FRUs

157.4 lb (71.4 kg)

19 in. (48.26 cm)

36.5 in. (92.7 cm) with the cable management brackets, air filter unit, and handles for fans and power supplies

5.21 in. (13.23 cm; 3 U)

DC-powered chassis fully loaded with all FRUs

163.4 lb (74.11 kg)

19 in. (48.26 cm)

38.5 in. (97.79 cm) with the cable management brackets, air filter unit, and handles for fans and power supplies

5.21 in. (13.23 cm; 3 U)

Chassis without any FRU installed

50 lb (22.68 kg)

19 in. (48.26 cm)

30 in. (76.2 cm) without the cable management brackets, air filter unit, and handles for fans and power supplies

5.21 in. (13.23 cm; 3 U)

Fan tray

1.5 lb (0.68 kg)

2.46 in. (6.25 cm)

9.27 in. (23.54 cm)

4.99 in. (12.6 cm)

Routing and Control Board

7.5 lb (3.4 kg)

7.98 in. (20.27 cm)

22.12 in. (56.18 cm)

1.66 in. (4.21 cm)

Air filter unit and cable management brackets

5.51 lb (2.5 kg)

19 in. (48.26 cm)

5.43 in. (13.79 cm)

5.19 in. (13.18  cm)

Line card

33 lb (14.97 kg)

16.5 in. (41.91 cm)

22.37 in. (56.82 cm)

1.65 in. (4.19 cm)

AC power supply

3.4 lb (1.54 kg)

3.53 in. (8.67 cm)

9.26 in. (23.52 cm)

1.63 in. (4.14 cm)

DC power supply

4.4 lb (1.99 kg)

3.53 in. (8.67 cm)

10.8 in. (27.43 cm)

1.63 in. (4.14 cm)

You can mount an EX9253 switch on four posts of a 19-in. rack or cabinet.

Field-Replaceable Units in an EX9253 Switch

Field-replaceable units (FRUs) are components that you can replace at your site. The FRUs in EX9253 switches are hot-removable and hot-insertable. You can remove and replace them without powering off the switch. The FRUs in EX9253 switches are:

  • Routing Engines

  • Power supplies

  • Fan trays

  • Air filter unit

  • Air filter

  • Line cards

  • Transceivers

The fan trays and power supplies are hot-removable and hot-insertable field-replaceable units installed in the rear panel of the switch. You can replace them without powering off the switch or disrupting switch functions. In a switch powered by AC power supplies, a minimum of two high line power supplies or three low line must be installed in the switch for non-redundant operation. To ensure proper operation of the switch, you must install a replacement power supply shortly after removing a power supply from the chassis. To maintain proper cooling, you must install a replacement fan tray or a blank panel in the fan tray slot shortly after removing a fan tray from the chassis.

Note

If you have a Juniper J-Care service contract, register any addition, change, or upgrade of hardware components at https://www.juniper.net/customers/support/tools/updateinstallbase/  . Failure to do so can result in significant delays if you need replacement parts. This note does not apply if you replace existing components with the same type of component.

To install a Routing and Control Board in an EX9253 switch, follow instructions in Installing a Routing Engine in an EX9253 Switch. To remove a Routing and Control Board from an EX9253 switch, follow instructions in Removing a Routing Engine from an EX9253 Switch.

To install an AC power supply in an EX9253 switch, follow instructions in Installing an AC Power Supply in an EX9253 Switch. To remove an AC power supply from an EX9253 switch, follow instructions in Removing an AC Power Supply from an EX9253 Switch.

To install a DC power supply in an EX9253 switch, follow instructions in Installing a DC Power Supply in an EX9253 Switch. To remove a DC power supply from an EX9253 switch, follow instructions in Removing a DC Power Supply in an EX9253 Switch.

To install a fan tray in an EX9253 switch, follow instructions in Installing a Fan Tray in an EX9253 Switch. To remove a fan tray from an EX9253 switch, follow instructions in Removing a Fan Tray from an EX9253 Switch.

To install the air filter unit in an EX9253 switch, follow instructions in Installing the Air Filter Unit in an EX9253 Switch. To remove the air filter unit from an EX9253 switch, follow instructions in Removing the Air Filter Unit from an EX9253 Switch.

To install the air filter in the air filter unit in an EX9253 switch, follow instructions in Installing the Air Filter in the Air Filter Unit in an EX9253 Switch. To remove the air filter from the air filter unit in an EX9253 switch, follow instructions in Removing the Air Filter from the Air Filter Unit in an EX9253 Switch.

To install a line card in an EX9253 switch, follow instructions in Installing a Line Card in an EX9253 Switch. To remove a line card from an EX9253 switch, follow instructions in Removing a Line Card from an EX9253 Switch.

To install a transceiver in an EX9253 switch, follow instructions in Install a Transceiver or Install a QSFP28 Transceiver. To remove a transceiver from an EX9253 switch, follow instructions in Remove a Transceiver or Remove a QSFP28 Transceiver.

Host Subsystem in an EX9253 Switch

The host subsystem provides switching protocol processes as well as software processes that control the switch’ s interface, the chassis components, system management, and user access to the switch. These switching processes run on top of a kernel that interacts with the Packet Forwarding Engine. The host subsystem consists of two Routing Engines (REs). The RE is an integrated board that provides Routing Engine and Control Board functionality and supports virtualization. If two REs are installed, one functions as the primary and the other functions as the backup. If the primary host subsystem (or either of its components) fails, the backup can take over as the primary.

The RE is a hot-removable and hot-insertable field-replaceable unit (FRU). You can remove and replace it while the switch is running without turning off power to the switch or disrupting switching functions. At least one RE must be installed in the switch. To ensure proper operation of the switch, you must install a replacement RE shortly after removing an RE from the chassis. The REs are installed in the slots labeled RE0 and RE1 on the front panel of the chassis.

Figure 1 shows the components on the faceplate of an RE.

Figure 1: Components on the Faceplate of an RE
Components on the Faceplate of
an RE
  1
USB port
  8
Time of day port with LEDs (ToD) (This port is reserved for future use)
  2
Management port (MGMT)
  9
BITS port with LEDs
  3
Console port (CON)
10
Clocking ports
  4
SSD LEDs
11
OFFLINE button
  5
SSDs
12
ONLINE LED
  6
Master LED (MST)
13
OK/FAIL LED
  7
Alarm LED (ALM)
14
RESET button

The ports on the RE connect the switch to external devices on which system administrators can issue Junos  OS CLI commands to manage the switch and to external clocking and timing devices. The functions of the ports are:

  • CON—Connects the switch to a system console through a serial cable with an RJ-45 connector attached.

  • MGMT—Connects the switch to a management device for out-of-band management. The port uses an autosensing RJ-45 connector to support 10-Mbps, 100-Mbps, or 1000-Mbps connections. Two small LEDs on the port (see Figure 2) indicate the connection in use: the Speed LED blinks in amber color when the speed is 1000  Mbps, in green color when the speed is 100  Mbps, and is unlit when the speed is 10  Mbps; the Link/Activity LED is lit green when traffic is passing through the port.

    Figure 2: LEDs on the Management Port
    LEDs on the Management Port
      1
    Speed LED
      2
    Link/Activity LED
  • BITS—Building-integrated timing supply (BITS) external clocking interface to connect to external clocking devices.

  • ToD—Time-of-day (TOD) port to connect external timing signal sources. This port is reserved for future use.

  • 10MHZ (one input and one output)—The 10-MHz timing connectors connect the switch to external clock signal sources. The clocking ports provide the synchronized output clocks from any one of the reference clock inputs based on the clock’ s priority.

  • PPS (one input and one output)—1-pulse-per-second (PPS) connectors connect the switch to external clock signal sources. The clocking ports provide the synchronized output clocks from any one of the reference clock inputs based on the clock’ s priority.

  • USB—The USB port provides a removable media interface. Junos  OS supports USB version 1.0 and later.

Understanding EX9253 Switch Component and Functionality Redundancy

The Juniper Networks EX9253 Ethernet Switches are available as fully redundant system. A redundant EX9253 switch configuration is designed so that no single point of failure can cause the entire switch to fail. See EX9253 Switch Configurations.

The following hardware components provide redundancy to an EX9253 switch:

  • Host Subsystem—The host subsystem provides switching protocol processes as well as software processes that control the switch’ s interface, the chassis components, system management, and user access to the switch. These switching processes run on top of a kernel that interacts with the Packet Forwarding Engine. The host subsystem consists of two Routing Engines (REs). The RE is an integrated board that provides Routing Engine and Control Board functionality and supports virtualization. If two REs are installed, one functions as the primary and the other functions as the backup. If the primary host subsystem (or either of its components) fails, the backup can take over as the primary.

    If the Routing Engines are configured for graceful switchover, the backup Routing Engine automatically synchronizes its configuration and state with the primary Routing Engine. Any update to the primary Routing Engine state is replicated on the backup Routing Engine. If the backup Routing Engine assumes primary role, packet forwarding continues through the switch without interruption. See Host Subsystem in an EX9253 Switch.

  • Power supplies—The switch supports six power supplies, installed on the rear panel of the chassis in slots PEM0 through PEM5 (left to right). In a switch powered by AC power supplies, a minimum of two high line power supplies or three low line must be installed in the switch for non-redundant operation. In a redundant configuration, if one power supply fails or is removed, the remaining power supplies assume the entire electrical load without interruption. In a base configuration, if one power supply fails or is removed, one of the line cards is disabled. See EX9253 Power System.

  • Cooling system—The cooling system consists of four fan trays and an air filter unit. Each fan tray contains two counter-rotating fans. The fan trays are installed on the rear panel of the chassis. A fully configured switch needs all the four fan trays to operate normal. In the event of any fan failure, the fan tray with the faulty fan must be replaced immediately. You cannot replace a single fan. If one or more fans fail, you must replace the entire fan tray. Under normal operating conditions, the fans in the fan trays run at less than full speed. If a fan tray fails or the ambient temperature rises above a threshold, the speed of the remaining fan trays is automatically adjusted to keep the temperature within the acceptable range. If the ambient maximum temperature specification is exceeded and the system cannot be adequately cooled, the Routing Engine shuts down the line card that cannot be cooled adequately is disabled. If the fire threshold temperature is exceeded, the Routing Engine shuts down the system by disabling output power from each power supply. See EX9253 Cooling System.