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Alternatives for ring topology - EX3400/EX4600

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  • 1.  Alternatives for ring topology - EX3400/EX4600

    Posted 08-23-2017 14:11



    I'm planning to setup a network in one of our locations based on a number of VCs that due to physical limitations have to be connected togetter in a ring topology. I have been searching for a while for protocol alternatives in this situation, or is the only supportet protocol xSTP in the situation? Do Juniper provide any aditional options here? I looked at ERP, but this is not supported by EX3400.


    Quick schematic:



    Best regards,

    Johan Christensson


  • 2.  RE: Alternatives for ring topology - EX3400/EX4600

    Posted 08-23-2017 20:22

    The answer is to use ERPS (G.8032).  This is supported on many EX switches, and I "THINK" it should also be there on EX3400, but I am not 100% sure, and documentation is not clear.  This support is there on EX4600 and EX4300, as well legacy EX switches, that is why I 'think' it should be there on EX3400.  For info see this link:




    Since VC itself is actually a ring topology (ISIS under the cover, L2 on top) you could make such a configuration easily with a mixed-chassis of EX4600 and EX4300.  Unfortunately, you have EX3400 which can NOT VC with EX4600.


    I'd really suggest you discuss your needs (which I assume are some what based on Fiber plant lay-out) with your Juniper Partner or Sales team to come-up with the best approach.  Of course xSTP will work for this, but there might be better alternatives depending upon your exact needs.


    Good luck.

  • 3.  RE: Alternatives for ring topology - EX3400/EX4600

    Posted 08-23-2017 23:24

    Thanks for your reply.

    Well, that was one thought that I had first, to make larger VCs since each can consist of 10 devices we chould group the 7 chassis down to 3 chassis. But we still would have to connect the 3 chassis together and "uplink" them to the ex4600 that is the distribution point in this case.

    Regarding ERPS, well looking at the feature navigatet most EX models seems to support it, even the smaller compact versions, but for some reason the EX3400 isen't listed and the command is not available in the cli either. Feels a bit strange since we have some old EX3300, and they seems to support ERPS.

    I have raised the question with our Juniper partner, but I still would like to educate my self and hear thought and ideas from the user community.

    Best regards,
    Johan Christensson

  • 4.  RE: Alternatives for ring topology - EX3400/EX4600
    Best Answer

    Posted 08-24-2017 02:20

    Hi Johan,


    you are right in your finding regards EX3400. It does not support ERPS which brings you down to classic xSTP.


    An option for lowering the impact for a break in the ring could be doing two links on each hop and bundle them together in an aggregated ethernet (ae) interface which keeps the logical link up in case of optics failure or repatch error in a patchpanel. Not pretty but better than nothing.


    Alternatively you could look into some (passive) DWDM multiplexers with OADM's beside each EX3400 VC making it possible for you to connect all EX3400 VC's directly to the EX4600 VC via ae's. This would require single mode cabling all over and some extra cost for optics, multiplexers and OADM's...

  • 5.  RE: Alternatives for ring topology - EX3400/EX4600

    Posted 10-06-2017 08:43

    I ended up going with classic RSTP to get ut up and running, although depending on how long this network is going to be needed, we might "upgrade" it with MSTP.


    It is strange that the ES3400 seems to be a "low-end" product, if you look at the feature set and in comparison with smaller brother ex2300 or big-brother ex 4300.


    Thanks for all input!


    Best regards,

    Johan Christensson