Description

This article provides more information about the internal interfaces, em0 and em1, on the Routine Engine (RE) in the MX240/480/960 Series of devices, and also details the message walk path from the primary RE to the backup RE, and from the RE to the Flexible PIC Concentrator (FPC).

 

Solution

em0 and em1 are the internal interfaces on the Routine Engine (RE).

  • em0 is the interface connected to the Ethernet switch on the local Switch Control Board (SCB).

  • em1 is the interface connected to the Ethernet switch on the other SCB.

 

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The message path between each component is as follows:

  • Primary RE to backup RE: Primary RE (em1) → Ethernet switch on backup SCB → (em0) backup RE

  • Backup RE to Primary RE: Backup RE (em1) → Ethernet switch on primary SCB → (em0) primary RE

  • Primary RE to FPC: Primary RE (em0) → Ethernet switch on primary SCB → FPC

  • FPC to primary RE: FPC → Ethernet switch on primary SCB → (em0) master RE

  • Backup RE to FPC: Backup RE (em1) → Ethernet switch on master SCB → FPC

  • FPC to backup RE: FPC → Ethernet switch on backup SCB → (em0) backup RE

 

Commands to check status and statistics

  • To check the connection on the Ethernet switch: 

    • show chassis ethernet-switch

  • To check the Ethernet switch statistics: 

    • show chassis ethernet-switch statistics
    • show chassis ethernet-switch port-state

  • To check em0 status and statistics: 

    • show interfaces em0 extensive

  • To check em1 status and statistics: 

    • show interfaces em1 extensive

  • To check the components on the SCB and RE: