EX9251 System Overview
EX9251 Switch Hardware Overview
Juniper Networks EX9251 Ethernet Switch is an Ethernet-optimized switch that provides carrier-class Ethernet switching. It is a fixed configuration switch with a built-in Routing Engine. It has a throughput of up to 400 gigabits per second (Gbps).
The switch has eight 10-Gigabit Ethernet ports and four rate-selectable ports that you can configure as 100-Gigabit Ethernet ports or 40-Gigabit Ethernet ports; each rate-selectable port can be configured as four 10-Gigabit Ethernet ports by using a breakout cable. The 10-Gigabit Ethernet ports support SFP+ transceivers and rate-selectable ports support QSFP28 and QSFP+ transceivers. The switch supports two power supplies and three fan trays.
Juniper Networks EX Series Ethernet Switches run Junos OS, which provides Layer 2 and Layer 3 switching, routing, and security services. The same Junos OS code base that runs on EX Series switches also runs on all Juniper Networks M Series, MX Series, and T Series routers, and SRX Series Services Gateways.
Benefits of the EX9251 Switch
Simplified network architecture—EX9251 switches deliver a simple, secure, virtualized network environment that increases business agility. They are ideal for simplifying campus, data center, and combined campus and data center network environments by collapsing network layers.
Support for Junos Fusion Enterprise—EX9251 switches support Junos Fusion Enterprise technology that enables a large number of devices deployed throughout a building to be managed as a single, logical device, thus reducing network complexity, simplifying network management, and lowering operational costs.
EX9251 Switch Models
EX9251 switch is available in two models—with AC power supply and with DC power supply. See EX9251 Switch Models.
Front Panel of an EX9251 Switch
Figure 1 shows the front panel of an EX9251 switch.
Rate-selectable ports—These ports can operate in 100G, 40G, and 10G speeds and support transceivers and direct attach copper (DAC) cables.
Reset button—button to reset the switch.
Management Ethernet port—This port connects the switch to a management device (or any other device that plugs into an Ethernet connection) for out-of-band management through an Ethernet connection. The port uses an autosensing RJ-45 connector to support 10-Mbps, 100-Mbps, or 1000-Mbps connections.
SSD0 LED—indicates the status of the solid-state drive labeled
BITS ports with LEDs—Building-integrated timing supply (BITS) external clocking port, that connects the switch to external clocking devices.
Alarm LED—indicates alarms.
USB port—USB port, that provides a removable media interface that you can use to install Junos OS manually. Junos OS supports USB version 1.0 and later.
OK/Fail LED—indicates the status of the switch.
1PPS and 10 MHz GPS input and output timing ports—1-pulse-per-second (PPS) connectors and 10-MHz timing connectors respectively (one input and one output), that connects 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.
Time of day (ToD) port with LED—ToD port, that connects the switch to external timing signal sources.
Online LED—indicates the status of the switch and the operating system.
Console port—Console port, that connects the switch to a system console through a serial cable with an RJ-45 connector.
SSD1 LED—indicates the status of the solid-state drive labeled
10-Gigabit Ethernet SFP+ ports—support SFP+ transceivers and direct attach copper (DAC) cables.
Offline button—button to turn the switch online or offline or to power on or power off the switch.
PTP grandmaster clock (GM/PTP) port—PTP grandmaster clock port, that connects the switch to a timing device. Support for this port is not available in this release.
Rear Panel of an EX9251 Switch
Protective earthing terminal
Fan tray LEDs
Electrostatic discharge (ESD) point
AC power supply units
DC power supply units
EX9251 switches have a single built-in Routing Engine. It provides switching protocol processes and 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 Routing Engine is built-in on the baseboard and cannot be replaced.
It supports the following functionalities to manage the operation of the switch:
System control functions such as environmental monitoring
Routing Layer 2 and Layer 3 protocols
Communication to components such as power supplies and fan trays
Alarm and logging functions
It consists of the following internal components:
High-performance 1.6-GHz Intel 8 Core X86 CPU
32-GB DDR4 RAM
2x100-GB SATA SSD
EX9251 switches support AC power supply and DC power supply. See Power Supplies in an EX9251 Switch.
Do not mix AC and DC power supplies in the same chassis.
The cooling system in an EX9251 switch consists of three fan trays. The fan trays are installed on the rear panel of the chassis. Each fan tray contains one counter rotating fan. See EX9251 Cooling System.
A fully configured EX9251 switch is designed such that no single point of failure can cause the entire system to fail. The following major hardware components are redundant:
Power supplies—The switch supports two power supplies. If one power supply fails in a fully configured switch, the other power supply can provide full power to the switch.
Cooling system—The switch supports three fan trays. If one fan fails or the temperature of the chassis rises above the temperature threshold in a fully configured switch, the speed of the remaining fans is automatically adjusted to keep the temperature within the acceptable range.
In a fully configured switch, all the three fan trays and the two power supplies must be operational. In the event of any failure, the failed component must be replaced immediately.
EX9251 Switch Models
EX9251 is available in two models—with AC power supply and with DC power supply. Table 1 lists the models and the components included in each model.
Table 1: EX9251 Switch Models
First Junos OS Release
EX9251 Switch Hardware and CLI Terminology Mapping
This topic describes the hardware terms used in EX9251 switch documentation and the corresponding terms used in the Junos OS CLI. See Table 2.
Table 2: CLI Equivalents of Terms Used in Documentation for EX9251 Switches
Hardware Item (CLI)
Item in Documentation
Abbreviated name of the Physical Interface Card (PIC). One of the following:
n is a value in the range 0-1. The value corresponds to the PIC slot number.
Abbreviated name of the transceiver.
n is a value equivalent to the number of the port in which the transceiver is installed.
One of the following:
n is a value in the range 0-1. The value corresponds to the power supply slot number.
AC or DC power supply
Fan tray (n)
Fan Tray, Front to Back Airflow - AFO
n is a value in the range 0-2. The value corresponds to the fan tray slot number.
Table 3 lists the spare parts and blank panels available for the switch. They must be ordered separately.
Table 3: Spare Parts and Blank Panels
EX9251 chassis, spare
EX9251 power supply slot blank panel