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MX204 Host Subsystem

 

MX204 Routing Engine Description

The host subsystem provides routing protocol processes, as well as software processes that control the router’s interface, the chassis components, system management, and user access to the router. These routing processes run on top of a kernel that interacts with the Packet Forwarding Engine. The MX204 host subsystem consists of a single built-in Routing Engine.

This topic covers:

Routing Engine Functions

The Routing Engine is built-in on the MX204 baseboard and cannot be replaced. The Routing Engine performs all route-processing functions, and provides performs chassis control and management plane functionality. The Routing Engine also provides control plane functions.

The Routing Engine supports the following functionalities to manage the operation of the router:

  • System control functions such as environmental monitoring

  • Routing Layer 2 and Layer 3 protocols

  • Communication to components such as line cards, power supply, and cooling system

  • Transparent clocking

  • Alarm and logging functions

Routing Engine Components

The Routing Engine consists of the following internal components:

  • High-performance 1.6-GHz Intel 8 Core X86 CPU

  • 32-GB DDR4 RAM

  • 100-GB SATA SSD

Routing Engine Front Panel

Figure 1 shows the front panel of the MX204 chassis.

Figure 1: MX204 Ports
MX204 Ports
  1
Rate-selectable ports
  9
RESET button
  2
Management (MGMT) port
10
SSD0 LED
  3
BITS port with LEDs
11
Alarm (ALM) LED
  4
USB port
12
OK/FAIL LED
  5
1PPS and 10MHz GPS input and output ports
13
Time of day (ToD) port with LEDs (This port is reserved for future use)
  6
ONLINE LED
14
Console (CON) port
  7
SSD1 LED
15
10-Gigabit Ethernet SFP+ ports
  8
OFFLINE button
16
PTP grandmaster clock (GM/PTP) port

Routing Engine Interface Ports

The ports located on the router connect the Routing Engine to one or more external devices on which system administrators can issue Junos OS CLI commands to manage the router. In addition, ports to connect external clock interfaces for BITS and GPS function are also available on the router.

The Routing Engine interface ports with the indicated labels function are as follows (see Figure 1):

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

  • MGMT—Connects the Routing Engine through an Ethernet connection to a management LAN (or any other device that plugs into an Ethernet connection) 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 indicate the connection in use: the LED flashes yellow or green for a 10-Mbps, 100-Mbps, or 1000-Mbps connection, and the LED is lit green when traffic is passing through the port.

  • BITS—Building-integrated timing supply (BITS) external clocking interface for connecting to external clocking devices.

  • ToD—Time-of-day (TOD) port on the front panel of the router that enables you to connect external timing signal sources.

    Note

    This port is reserved for future use.

  • 10MHZ (one input and one output)—The 10-MHz timing connectors on the front panel of the router that connect 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 on the front panel of the router that connect 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—Provides a removable media interface through which you can install Junos OS manually. Junos OS supports USB version 1.0 and later.

MX204 Routing Engine LEDs

The Routing Engine is built-in on the MX204 and is attached to the baseboard and cannot be replaced. The status of the Routing Engine is displayed by the ONLINE and OK/FAIL LEDs on the front panel of the MX204 chassis.

Table 1 describes the functions and LEDs on the MX204 router.

Note

The functioning of the MX204 router is controlled by the Routing Engine, and the LEDs present on the front panel of the router displays the status and functioning of the MX204 router.

Table 1: MX204 LEDs

Label

Color

State

Description

ONLINE

Green

On steadily

Both Junos OS and Linux are successfully loaded on the router.

Blinking

Router is starting Junos OS.

Red

On steadily

Router has loaded Linux.

Blinking

Router is starting Linux.

Off

Router is offline.

OK/FAIL

Green

On steadily

Router is functioning normally.

Red

Blinking

Router has failed.

Off

Router is not powered on.

ALM

Red

On steadily

Critical alarm—Indicates a critical condition that can cause the router to stop functioning. Possible causes include component failure, or any major software failure.

Yellow

On steadily

Warning alarm—Indicates a serious but nonfatal error condition, such as a maintenance alert or a significant increase in component temperature.

Off

There is no alarm.

SSD0

Green

Blinking

SSD0 is being accessed by the router.

Off

SSD0 is not active or not being accessed.

SSD1

Green

Blinking

SSD1 is being accessed by the router.

Off

SSD1 is not active or not being accessed.

BITS

Green

On Steadily

(Activity LED; left)

When there is no loss (BITS is in locked state).

Off

(Activity LED; left)

When there is loss of signal or loss of line.

Amber

On steadily

(Link LED; right)

When there is loss of signal or loss of line.

Off

(Link LED; right)

When there is no loss (BITS is in locked state).