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  • 1.  EX series failover times

    This message was posted by a user wishing to remain anonymous
    Posted 01-28-2022 09:29
    This message was posted by a user wishing to remain anonymous


    I am looking to deploy a number of switches and switch stacks(VC) within our network and would like to try and find out what the expected failover times and failover options are for these switches:

    - EX2300
    - EX4300
    - EX4600

    We are using two EX4600s in VC to aggregate a mix of 2300/4300/4600s as single switches or in stacks of two, all switches will be running Layer 2 only apart from management/QoS.

    VC links will be either 10g or 1g ports, uplink ports from access to aggregation will be 2x 10g links in a LAG, I am looking for information such as:

    - If one port in the LAG fails for a single switch or VC, how much downtime if any is expected
    - If one switch in a VC fails, how much downtime is expected before the second switch takes over

    And what methods are available to reduce failover time.

    Thanks in advance,


  • 2.  RE: EX series failover times

    Posted 02-01-2022 10:06

    Chris Limbert

  • 3.  RE: EX series failover times

    Posted 02-01-2022 10:21
    Hi Chris,

    without knowing the exact topology and protocols involved I can just make assumptions.

    If you run LACP over the LAG and the „active" link fails, the Backup Link needs to „converge" so I would expect 1-2 ping losses from Experience.

    Usually a VC (especially a 2-Member VC) is really really fast.
    You will most likely use 1 or 2 pings when the Backup switches to the Master state. In a 2-Member-VC you already have both devices running on the role routing-engine so failover shouldn't be a problem :) But I usually test this in a quick PoC in order to know that my topology is running the way I want it to be running.

    That being said the EX2300 has a weaker CPU than the 4300 so it might be possible to see a 3-4 ping delay if the switch also has a heavy load - but again - I can only assume than as I don't know your topology.

    Christian Scholz
    Juniper Networks Ambassador | JNCIE-SEC #374
    Mail: chs@ip4.de
    Blog: jncie.eu | Twitter: @chsjuniper | YT-Channel: netchron