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M120 Routing Engine Interface Ports and Status Indicators


To the right of the alarm relay contact on the craft interface are two sets of ports that connect the Routing Engines to one or more external devices on which system administrators can issue Junos OS command-line interface (CLI) commands to manage the router (see Front Panel of the Craft Interface). The set of ports in the left connects to the Routing Engine in the left Routing Engine slot (REO) and the set on the right connects to the Routing Engine (RE1) in the right Routing Engine slot.

The ports with the indicated label in each set function as follows:

  • AUX—Connects the Routing Engine to a laptop, modem, or other auxiliary device through a cable with an RJ-45 connector.

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

  • ETHERNET—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 both 10- and 100-Mbps connections. Two small LEDs on the bottom of the port indicate the connection in use: the LED lights yellow or green for a 10-Mbps or 100-Mbps connection, and the LED lights green when traffic is passing through the port.