Understanding EX8208 Switch Component and Functionality Redundancy
The Juniper Networks EX8208 Ethernet Switch is available as a fully redundant system. A redundant EX8208 switch configuration is designed so that no single point of failure can cause the entire switch to fail. See EX8208 Switch Configurations.
Hardware Components That Provide Redundancy
The following hardware components provide redundancy to an EX8208 switch:
SRE modules—An EX8208 switch can have either one Switch Fabric and Routing Engine (SRE) module or two SRE modules. If two SRE modules are installed, one SRE module functions as the master and the other functions as the backup. If the master SRE module fails or is removed the backup module takes over as the master SRE module.
When the SRE modules are configured for graceful switchover, the backup SRE module automatically synchronizes its configuration and state with those of the master SRE module. Any update to the master SRE module is replicated on the backup SRE module. If the backup module assumes mastership, packet forwarding continues through the switch.
Power supplies—You can install up to six AC or six DC power supplies in an EX8208 switch. Each power supply connects to the backplane of the chassis, which distributes the output power produced by the power supplies to different switch components. (See Backplane in an EX8208 Switch.) Each power supply provides power to all the components in the switch.
An N+1 power configuration is required for Juniper Networks EX8200 Ethernet Switches. In an N+1 power configuration, if one power supply fails or is removed, the remaining power supplies continue to supply power for the entire system without interruption. If dual power feed redundancy is required, the required power configuration is N+N. The DC power supplies provide independent A and B power feeds so that dual power redundancy is available even in an N+1 power configuration. See AC Power Supply in an EX8200 Switch and DC Power Supply in an EX8200 Switch.
Cooling system—The cooling system in an EX8200 switch consists of a single fan tray. The fan tray contains 12 fans. Under normal operating conditions, the fans in the fan tray run at less than full speed.
The fans are controlled by two fan tray controllers. The fans are numbered 1 through 12. Fans 1 through 6 are controlled by the first fan tray controller. Fans 7 through 12 are controlled by the second fan tray controller. If one fan tray controller fails, the other fan tray controller keeps half the fans working. This allows the switch to continue to operate normally as long as the remaining fans cool the chassis sufficiently.
The fan tray continues to operate indefinitely and provides sufficient cooling even when a single fan fails provided the room temperature is within the operating range. See EX8208 Cooling System.
Routing Engine and Control Redundancy
Each SRE module contains switch fabric circuitry, Routing Engine circuitry, and switch control and management circuitry. An EX8208 switch can have one SRE module or two SRE modules. If a switch has two SRE modules, one functions as the master while the other functions as a backup and is in standby mode. This provides the switch with full redundancy (1+1) for Routing Engine and switch control functionality.
Table 1 shows the available slots in the EX8208 chassis and the Routing Engine and control redundancy associated with different SRE module and Switch Fabric (SF) module combinations.
Table 1: Routing Engine and Control Redundancy for EX8208 Switches
Routing Engine and Control Redundancy
Switch Fabric Redundancy
The switch fabric circuitry in an EX8208 switch is distributed across three modules—two SRE modules and one SF module. Any two of these three modules must be installed and functional to provide a working switch fabric with no redundancy. The third module, when present, provides partial redundancy (2+1) for the switching functionality, such that if any one of the two functional modules becomes nonoperational, the third module takes over.
Table 2 shows the available slots in an EX8208 chassis and the switch fabric redundancy associated with different SRE module and SF module combinations.
Table 2: Switch Fabric Redundancy for EX8208 Switches
Switch Fabric Redundancy
Slot Numbering for an EX8208 Switch
An EX8208 chassis accepts eight line cards, two Switch Fabric and Routing Engine (SRE) modules, one Switch Fabric (SF) module, one fan tray, and six power supplies (AC or DC). All 11 slots for the line cards and the modules run horizontally across the front of the chassis. The fan tray slot runs vertically on the left of the chassis front. The six power supply slots run vertically across the front bottom of the chassis.
Slot Numbering for SRE and SF Module Slots and Line Card Slots
Table 3 lists the slot numbers on the EX8208 chassis and the components those slots accept.
Table 3: Slot Numbering for an EX8208 Switch
Components Accepted in Slot
Figure 1 shows the slot numbering, which is on the front left of the chassis.
Figure 1 shows line cards that have 2-in.-long ejector levers. An earlier version of 8-port SFP+ line card, 48-port RJ-45 line card, and 48-port SFP line card has 4-in.-long ejector levers.
Slots 0 through 7 accept one of the line cards available. See Installing a Line Card in an EX8200 Switch.
Slots SRE0 and SRE1 accept only the SRE module. You can install one SRE module or two SRE modules based on the configuration of your switch. See Switch Fabric and Routing Engine (SRE) Module in an EX8208 Switch.
We recommend that you install two SRE modules for redundancy. If you install only one SRE module, we recommend that you install it in the slot SRE0. See Installing an SRE Module in an EX8208 Switch.
Slot SF accepts only the SF module. See Switch Fabric (SF) Module in an EX8208 Switch. An EX8208 switch can have either zero SF modules or one SF module based on your switch configuration. The SF module is keyed so that it does not fit in any other slot in the chassis. See Installing an SF Module in an EX8208 Switch.
Slot Numbering for the Power Supply Slots
The chassis has six vertical slots on its front bottom. You can install up to six power supplies (either all AC or all DC) in these slots, which are labeled PSU 0 through PSU 5 (from left to right). Table 4 lists the slot numbers for the power supplies on an EX8208 switch. See AC Power Supply in an EX8200 Switch and DC Power Supply in an EX8200 Switch.
Mixing different types of power supplies in the same chassis is not a supported configuration.
Table 4: Slot Numbering for Power Supply Slots on an EX8208 Switch Chassis Front
Components Accepted in Slot
Figure 2 shows the slot numbering for the power supply slots in an EX8208 switch.
Power supplies can be installed in any slot. You do not have to install them in serial order. See Installing an AC Power Supply in an EX8200 Switch and Installing a DC Power Supply in an EX8200 Switch.
LCD Panel in an EX8200 Switch
The LCD panel on the top front of the EX8200 switch chassis shows two lines of text with a maximum of 16 characters in each line. The LCD panel displays a variety of information about the switch and provides menu options to perform basic operations such as initial configuration and switch reboot.
There are two navigation buttons—Menu and Enter—to the right of the LCD panel.
See Figure 3.
You can configure the second line of the LCD panel to display a custom message. If the LCD panel is configured to display a custom message, the Menu button and the Enter button are disabled. See Configuring the LCD Panel on EX Series Switches (CLI Procedure).
The LCD panel has a backlight. If the LCD panel is idle for 60 seconds, the backlight turns off. You can turn on the backlight by pressing the Menu or Enter button once. After turning on the backlight, you can toggle between the LCD menus by pressing the Menu button and navigate through the menu options by pressing the Enter button.
The chassis viewer in the J-Web interface also displays the LCD panel. From the J-Web interface, you can view real-time status information in the LCD panel. See Dashboard for EX Series Switches.
LCD Panel Modes
The LCD panel operates in four modes: boot, idle, status, and maintenance.
The LCD panel operates in boot mode during switch reboot.
The boot mode displays the key milestones in the switch boot process. The boot mode does not have any menu options. After the boot process is complete, the LCD panel automatically reverts to the Idle menu.
In the idle mode, line two of the Idle menu displays the Status LED modes of the network ports and the total number of alarms in the system. The number of alarms is updated every second.
The status mode allows you to get status information for the following items:
Switch fabric in Switch Fabric and Routing Engine (SRE) modules in EX8208 switches
Routing Engine (RE) and switch fabric in Switch Fabric (SF) module(s) in EX8216 switches
Fan tray(s) and chassis temperature
Junos OS version installed
The maintenance mode allows you to cycle through options for configuring and troubleshooting the switch:
Load rescue configuration
Revert to factory configuration
LCD Panel Menus
The LCD panel has three menus: Idle, Status, and Maintenance. In each of these menus, line one of the LCD panel displays the hostname of the switch. Toggle between the LCD menus by pressing the Menu button. Navigate through the menu options by pressing the Enter button.
Table 5 describes the LCD panel menu options.
Table 5: LCD Panel Menu Options for the EX8200 Switch
In the Idle menu:
The Status menu has the following options:
If you do not want users to use Status menu options, disable the entire menu or individual menu options. See Configuring the LCD Panel on EX Series Switches (CLI Procedure).
The Maintenance menu has the following options:
If you do not want users to use Maintenance menu options, disable the entire menu or individual menu options. See Configuring the LCD Panel on EX Series Switches (CLI Procedure).
You can view the information about the LCD panel in EX8200 switches by executing the command show chassis hardware. It shows the version, part number, serial number, and description of the LCD panel.
Backplane in an EX8208 Switch
The backplane is a printed circuit board that forms the back of the line card cage. The Switch Fabric and Routing Engine (SRE) modules, Switch Fabric (SF) module, power supplies, and line cards plug into the backplane from the front of the chassis. The backplane contains an EEPROM that stores the serial number and revision level of the backplane.
The backplane performs the following functions:
Power distribution—The backplane distributes power to all the switch components from the power supplies that plug into it.
Control-signal connectivity—The backplane transports the control signals exchanged by system components for monitoring, control, and management purposes.
Transfer of data between line cards and SRE modules—The backplane provides connectivity for data traffic to and from the line cards and the SRE modules.
High levels of electrical energy are distributed across the switch backplane. Do not touch the backplane connectors, or any component connected to the backplane, with any metallic object while servicing components installed in the switch.
Chassis Status LEDs in an EX8200 Switch
The top front of the chassis of an EX8200 switch has three LEDs on the right side of the LCD panel.
See Figure 4.
Table 6 describes the chassis status LEDs in an EX8200 switch, their colors and states, and the status they indicate. You can view the colors of the three LEDs remotely through the CLI by issuing the operational mode command show chassis lcd.
Table 6: Chassis Status LEDs in an EX8200 Switch
LED Label (Description)
State and Description
Switch is powered off.
One or more component failures are generating one or more alarms.
Switch is operating normally.
Switch is powered off.
Master Routing Engine is operational.
A major alarm (red) indicates a critical error condition that requires immediate action.
A minor alarm (yellow) indicates a noncritical condition that requires monitoring or maintenance. A minor alarm that is left unchecked might cause interruption in service or performance degradation.
All three LEDs can be lit simultaneously.
Network Port LEDs in an EX8200 Switch
Each network port on the faceplate of a line card has two LEDs. Figure 5 shows the network port LEDs on the line cards.
The LEDs labeled Link/Activity in Figure 5 indicate link activity.
Table 7 describes the Link/Activity LED.
Table 7: Network Port LEDs on Line Cards in an EX8200 Switch—Link/Activity LED
State and Description
The LEDs labeled Status in Figure 5 indicate the status of one of the three port parameters. The port parameters are administrative status, speed, duplex mode, and Power over Ethernet (PoE) status.
Table 8 describes the Status LED. From the Idle menu of the LCD panel, use the Enter button on the LCD panel to toggle between the ADM, SPD, DPX, and POE indicators.
Table 8: Network Port LEDs on Line Cards in an EX8200 Switch—Status LED
State, Color, and Description
Indicates the administrative status (enabled or disabled). The status indicators are:
Indicates the speed. The speed indicators are different in the line cards.
The speed indicators for 8-port SFP+ line cards are:
The speed indicators for 40-port SFP+ line cards are:
The speed indicators for EX8200-2XS-40P line cards are:
The speed indicators for EX8200-2XS-40T line cards are:
The speed indicators for EX8200-48PL line cards are:
The speed indicators for EX8200-48TL line cards are:
The speed indicators for 48-port SFP line cards are:
The speed indicators for 48-port RJ-45 line cards are:
Indicates the duplex mode. The status indicators are:
Indicates the PoE mode. The status indicators are: