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Upgrading MX104

  • 1.  Upgrading MX104

    Posted 08-11-2021 15:25
    Hello Junos Community,

    I am planning to upgrade Juniper MX104 router. I have read articles in juniper documentation that say there will be some down during RE switchover. 

    However, I want to understand how long the routing will remain down? Also, do interfaces also go down during switchover?


    Rahul Nangare

  • 2.  RE: Upgrading MX104

    Posted 08-11-2021 19:44
    If you configure you dual routing engines using both GRES and NSR you can perform the upgrade using ISSU and have no downtime during the upgrade.


    To upgrade each routing engine separately with manual switchover and card reboot downtime review these options.


    Steve Puluka BSEET - Juniper Ambassador
    IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP)

  • 3.  RE: Upgrading MX104

    Posted 08-12-2021 05:26
    Based on experience, if is a single Routing Enginer (RE), downtime is not beyond 17 minutes.


  • 4.  RE: Upgrading MX104

    Posted 08-12-2021 14:20
    Based on experience on MX104 / double RE:

    • normal update procedure (GRES / NSR disabled, no ISSU):
      • disable GRES/NSR
      • installation of update package on the backup RE (5 mn) – no downtime
      • 17 minutes to reboot/update the backup RE (no downtime) - actually when it reboots it immediately executes the install script and self-reboots again using now the new version
      • 5 minutes of downtime when you switchover to it (the forward-plane reboots and ports are down)
      • a few minutes for the routing to be operational (IGP/BGP), between 2 and many minutes depending of the number of BGP routes,
      • installation of update package on the new backup RE (5 mn) – no downtime
      • then 17 mn to reboot/update this RE
      • then you can re-enable GRES/NSR (and declare in the config the current master RE as master, and current backup as backup, in order to avoid «backup RE is active» alarm)
    • ISSU: you don't know when / how / how much you'll have downtime.

    Olivier Benghozi