40Gb Ethernet and 56Gb Infiniband cables equal?

[amrando]

I'm planning to get a couple of Mellanox Connectx-3 VPI 40Gb Ethernet/56Gb IB network cards.

 

When it comes to active optical cables (QSFP+), if the cable is rated for 40Gb, will it also handle 56Gb IB?

 

For example, this cable:

http://www.ebay.com/itm/Arista-Compatible-AOC-Q-Q-40G-15M-40G-QSFP-Active-Optical-Cable-AOC-15meters-/172630647034?hash=item283196a0fa:g:JPMAAOSwax5YoLv3

[Quinten Verhelst]

You will rarely see even close to the 40gb limit unless you're using a very complicated linux enviroment

 

[amrando]

I determined that I needed about 20 meters.  Pre-terminated 20m cables are pricey.  I decided that I would get optical transceivers and some LC-LC OM3 duplex multimode fiber, as it was quite a bit cheaper that way.  Hopefully it should work!

[leadeater]

Yea once you start going over 7m-10m you start getting in to compatibility problems as not everyone supports the same max lengths of active DAC cables vs passive DAC.

[harry4742]

On 20.4.2017 at 2:02 AM, amrando said:

I'm planning to get a couple of Mellanox Connectx-3 VPI 40Gb Ethernet/56Gb IB network cards.

Infiniband and Ethernet are different standards!

If you use Ethetnet you will see 40Gb

[Mornincupofhate]

What are you trying to do? Just curious.

[Tellos]

Sounds like he is trying to get a massive bandwidth boost. If the cable is rated for 40 you won't ever get 56 likely. Your bottleneck is the pipeline in your cable.