MX104 Chassis Overview
The MX104 router contains a front panel with slots in which you can install field-replaceable units (FRUs). From the front of the chassis, you can see the following components (see Figure 1):
Alarm console port labeled
ALARM, which accepts a DE-15 alarm cable.
Alarm LEDs that indicate major or minor alarms.
Built-in 10-Gigabit Ethernet MIC with four ports that accept 10-Gigabit Ethernet SFP+ transceivers.
Chassis status LED labeled
External building integrated timing system (BITS) port labeled
EXT REF CLOCK
External clocking ports supporting 1-PPS and 10-MHz input and output
Fan tray, which contains five fans and an air filter
Four slots for installing MICs
For a detailed description of the MX104 port and interface numbering see MX104 Port and Interface Numbering.
Two slots for installing either AC or DC power supplies, labeled
Two slots for installing Routing Engines, labeled
Alarm input and output contacts
10-Gigabit Ethernet SFP+ ports
MIC slots 0/1 and 1/1
Routing Engine slot 1
System status LED
Routing Engine slot 0
External reference clocking port
Power supply slot 1
Time-of-day (ToD) port
Power supply slot 0
1-PPS and 10-MHz GPS input and output ports
MIC slots 0/0 and 1/0
MX104 Hardware and CLI Terminology Mapping
The MX104 router supports the components in Table 1, listed in alphabetic order.
Table 1: MX104 Routers Hardware Components and CLI Terminology
Hardware Model Number
Cooling system, including fan trays and air filters
Air filter kit
Power system components
Power blank cover
4x 10GE(LAN) SFP+
MX104 Component Redundancy
The MX104 chassis provides redundancy and resiliency. The hardware system is fully redundant, including power supplies, Routing Engines, and cooling system.
A fully configured router is designed so that no single point of failure can cause the entire system to fail. Only a fully configured router provides complete redundancy. All other configurations provide partial redundancy. The following major hardware components are redundant:
Power supplies—In a redundant configuration, the router contains either two AC or DC power supplies that install into the front of the chassis. The slots are labeled
PS 1(left to right). Each power supply provides power to all components in the router. When two power supplies are present, they share power almost equally within a fully populated system. If one power supply in a redundant configuration fails or is removed, the remaining power supplies assume the entire electrical load without interruption. Two power supplies provide the maximum configuration with full power for as long as the router is operational.
Routing Engine—If two Routing Engines are installed, one functions as the primary and the other functions as the backup. If the primary Routing Engine fails, the backup can take over as the primary.
Cooling system—The cooling system has redundant components, which are controlled by the host subsystem. If one of the fans fails, the host subsystem increases the speed of the remaining fans to provide sufficient cooling for the router indefinitely.
MX104 Alarm Contact Port Overview
The MX104 router has four external alarm contacts (also known
as potential free contacts) for connecting the router to external
alarm devices. The port labeled
ALARM uses a
15-pin D-type connector. The external alarm contact has 15 pins that
accept a single core wire from external alarm devices. A DE-15 alarm
cable is required to connect the MX104 router to external alarm devices.
Use the gauge wire appropriate for the external device that you are
Whenever a system condition triggers an alarm, the alarm relay contacts are activated, which in turn activates the external alarm devices. The alarm setting is open or closed.
You can connect and configure two output alarms and four input alarms. Two additional output alarms are reserved and are used to indicate major and minor system alarms. Each output and input alarm has two contacts for connecting the router to external alarm devices. Contact 1 of each alarm can be configured as Normally Open [NO] or Normally Closed [NC] through the CLI. Contact 2 of each alarm functions as a reference [REF] or negative potential terminal for Contact 1 of the corresponding alarm and provides a current path for external alarm devices. Table 2 describes the functions of the alarm contacts.
Table 2: Alarm Relay Contact Functions
Normally Open [NO]
Current is not flowing through Contact 1 and Contact 2 [REF] when operating normally. When the current flows, the closed alarm is generated.
Normally Closed [NC]
Current is flowing through Contact 1 and Contact 2 [REF] when operating normally. When the current stops flowing, the open alarm is generated.
Provides the current path for the external alarm-reporting device and functions as a reference or negative potential terminal for Contact 1.
Figure 2 shows an example of a wiring diagram for a simple output alarm-reporting device. In this case, the device is a light bulb that illuminates when the device encounters a condition that activates the red alarm LED and relay contacts. The alarm relay contacts can also be used to activate other devices such as bells or buzzers.
Figure 3 shows an example of a wiring diagram for a simple input alarm-reporting device. In this case, the push button switch is an alarm sensor that triggers an input alarm when a door-open condition occurs.
MX104 LEDs Overview
Alarm LEDs on the Front Panel
Two LEDs, located to the right of the alarm contact port indicates major and minor alarms for the router (see Figure 4).
Table 3 describes the alarm LED in more detail.
Table 3: Alarm LEDs on the Front Panel
LED Control Name
Indicates a critical condition that can cause the router to stop functioning. Possible causes include component removal, failure, or overheating.
Indicates a serious but nonfatal error condition, such as a maintenance alert or a significant increase in component temperature.
System LED on the Front Panel
One bicolor LED labeled
SYS OK indicates
the status of the router. Table 4 describes
the system LED in more detail.
Table 4: System LED on the Front Panel
Router has no primary Routing Engine.
Router is functioning normally.
Router has reported a minor alarm.
Router has failed.
Each hot-removable and hot-insertable MIC has LEDs located on the faceplate. For more information about LEDs on the MIC faceplate, see the “LEDs” section for each MIC in the MX Series Interface Module Reference.
For information about the built-in MIC LEDs, see MX104 Modular Interface Card (MIC) Overview.
Power Supply LED
One LED labeled
PS STATUS indicates the
status of the power supply. For more information, see MX104 Power Overview.
Routing Engine LEDs
Three LEDs indicate the status of the Routing Engine. For more information, see MX104 Routing Engine Overview.