Security e-Series
Showing results for 
Search instead for 
Did you mean: 

JG325B and JG325A MPO Behaviour

Go to solution
Occasional Contributor

JG325B and JG325A MPO Behaviour

Hi Forums!

When one of the four fibre cables of an MPO connection drops, does it impact the remaining connections? ie: 40G -> Split to 4x 10G. If 1x10G is cut do the other 3x10G drop?

I read that the DACs can support each connection individually, but the MPO fiber I'm a little concerned about.


David Grocke


*EDIT I think answering my own question, but more to this. Do these SFPs or any MPO connection for that matter adhere to the IEEE 802.3ba-2010 40G standard where 64B/66B is used. I assume all MPO connections work this way, but I am struggling to find a definative answer. 

Ian Vaughan
Honored Contributor

Re: JG325B and JG325A MPO Behaviour


To the best of my knowledge, it depends :-)

If the port is configured as 4 virtual 10Gb interfaces losing "pair 1" will not impact pairs 2-4.

If the port is configured as one 40GbE interface utilising 8 cores of the MPO you need all 8 working as you'd expect.

MPO cables come in 2 types - straight-through (for structured) and cross-over for direct device  to device connectivity.

BTW - have you seen the BiDi options and the AOC cables that are coming through? Lots of bandwidth for less bucks, need to check the cable lengths and see if they fit your use case. QSFP28 on the new switches are even better bandwidth/$ - 100Gb for the price of a good lunch :-)

Hope that helps (kudos button is there if it does)



Hope that helps - please click "Thumbs up" for Kudos if it does
## ---------------------------------------------------------------------------##
Which is the only cheese that is made backwards?
Tweets: @2techie4me
Occasional Contributor

Re: JG325B and JG325A MPO Behaviour

Yep., you're a genus. Thanks! and yes, I'll stick to BiDi and 100G in the future :)