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Line card in Virtual Chassis and VC configuration

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  • 1.  Line card in Virtual Chassis and VC configuration

    Posted 01-20-2019 14:03

    Hi everybody.

    I just want to confirm my understanding:

    In Juniper implementation of Virtual chassis , Master /back RE stores/maintains Single copy for the whole virtul chassis  . Line card does not store/mainatain the whole Virtual Chassis config like Master /Back RE do.  Line card however stores some Virtual chassis config in its own private config file such as member id, vcp port config, 


    I am trying to find juniper doc that can confirnm the above .

    Am I correct?


    Have a nice weekend!!





  • 2.  RE: Line card in Virtual Chassis and VC configuration
    Best Answer

    Posted 01-22-2019 19:35

    My 2 cents. Consider VC as a big switch having multiple Routing engines. So configuration will be stored only on master and backup REs. Hope the following helps you.




    Master Routing Engine Role

    In a Virtual Chassis, each member switch is assigned one of two roles: Routing Engine role or linecard role, and for Routing Engine role, receives a further designation as the master or backup Routing Engine.

    The member that functions as the master in the Routing Engine role in the Virtual Chassis:

    • Manages the member switches.

    • Runs Junos OS for the switches as a master Routing Engine.

    • Runs the chassis management processes and control protocols.

    • Represents all the member switches interconnected within the Virtual Chassis configuration. (The hostname and other properties that you assign to this switch during setup apply to all members of the Virtual Chassis configuration.)

    Backup Routing Engine Role

    The member that functions in the backup Routing Engine role in a Virtual Chassis:

    • Maintains a state of readiness to take over the master Routing Engine role if the master fails.

    • Runs Junos OS for the switches as a backup Routing Engine.

    • Synchronizes with the master in terms of protocol states, forwarding tables, and other information, so that it is prepared to preserve routing information and maintain network connectivity without disruption in case the master is unavailable.

    Linecard Role

    A member that functions in the linecard role in a Virtual Chassis:

    • Runs only a subset of Junos OS.

    • Does not run the chassis control protocols.

    • Can detect certain error conditions (such as an unplugged cable) on any interfaces that have been configured on it through the master.