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MX960 dual RE: GRES and NSR

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  • 1.  MX960 dual RE: GRES and NSR

    Posted 04-17-2020 06:49

    Hi There,

     

    I am in the process to upgrade one mx960 with dual RE (re0 master and re1 backup).

    GRES, NSR, commit sync is already configured.

    Having GRES enable,  make the backup RE of being ready to keep on forwarding the traffic in case of switchover/failover: logically the  forwarding plane ready on backup RE.

    Having NSR enables, make  the backup RE of being ready to keep on routing the traffic in case of switchover/failover: control plan ready on backup RE.

    With NSR and GRES enabled, we are sure that on backup RE the process like chassissd, rpd are up, running.

    Now, before starting the upgrade is best practice to disable the GRES, NSR.

    As soon i complete the upgarde of backup RE RE1 i need to start upgrade of master RE RE0 and GRE and NSR and commit sync are disabled in this stage of the upgrade.

    As soon I swicthover the RE mastership from RE0 (still not upgraded) to RE1 (upgraded) with GRS+NSR disabled I am expecting the following situation:

    - RE1 will became the new master

    - The PFE will be automatically restarted and the new firmware will be loaded on to it.

    - RE1 will start to communicate with the PFE

    I hope i got it correctly.

    Question:

    - but what about the process like for example rpd/chassisd? I am expecting that without NSR+GRES enabled the backup RE RE1 has all the process down and will start them only when it will became master.

    The same is valid on the contrary: as soon RE0 will became backup RE (no GRE+NSR) than the process like rpd will be killed.

     

    Does it make sense? Is my understading correct?

     

    Thanks.



  • 2.  RE: MX960 dual RE: GRES and NSR

     
    Posted 04-17-2020 07:36

    Hi FabNewCert !

              Here is a KB that walks you through the process ; please review this and let me know if you have any questions. 

     

    https://kb.juniper.net/InfoCenter/index?page=content&id=KB8911&actp=METADATA

     

     

     

     

    Hope this helps !!

     Please accept this as a solution if it answers your question so others can benefit from your post.

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  • 3.  RE: MX960 dual RE: GRES and NSR

    Posted 04-17-2020 08:44

    Thank you but under the documentation point of view i already did all the research.

    This KB is quite good, I already almost memorize it in the last 2 weeks.  It is not really complete, especially in the part of disable the redundancy for RE.

    I agree though that is good starting point but it does not answer to my question.

     



  • 4.  RE: MX960 dual RE: GRES and NSR
    Best Answer

     
    Posted 04-19-2020 06:06

    You are describing here the correct process for manual upgrade without ISSU and with impact.

    Now, before starting the upgrade is best practice to disable the GRES, NSR.
    
    As soon i complete the upgarde of backup RE RE1 i need to start upgrade of master RE RE0 and GRE and NSR and commit sync are disabled in this stage of the upgrade.
    
    As soon I swicthover the RE mastership from RE0 (still not upgraded) to RE1 (upgraded) with GRS+NSR disabled I am expecting the following situation:
    
    - RE1 will became the new master
    
    - The PFE will be automatically restarted and the new firmware will be loaded on to it.
    
    - RE1 will start to communicate with the PFE

    All correct in this scenario

    Question:
    
    - but what about the process like for example rpd/chassisd? I am expecting that without NSR+GRES enabled the backup RE RE1 has all the process down and will start them only when it will became master.
    
    The same is valid on the contrary: as soon RE0 will became backup RE (no GRE+NSR) than the process like rpd will be killed.

    Basically correct.  What happens when you failover without GRES/NSR is that the new RE restarts all your line cards per the normal chassis startup process.  During this all the processes are starting fresh and loading all the normal startup data starting with the chassis and cards and building up from there.  The time on the process depends on the number of cards installed and can be quite long, be patient.

     

    In these situations it is helpful to have local console access to both RE so you can monitor the progress.  This makes the wait much calmer as you can see what is happening along the way.