QSFP+ to SFP+ Breakout cable question

[Bjorn Smith]

Hi,

I am wondering if I buy a QSFP+ to SFP+ Breakout cable, like one of these:
40G QSFP+ Cables, QSFP+ to 4 SFP+ Breakout Copper Cables

Do I need to plug in all 4 SFP+ cables or can I just use one or as many as I like?

I am asking since I have a QSFP+ switch (Mellanox) - and a Netgear switch I would like to connect together, but my Netgear switch only have two SFP+ ports - so I would only be able to use at most two of the four SFP+ connectors.

Thanks in advance for any replies.

 

[fohdeesha]

you can use however many you want, even just one. When QSFP+ switch ports operate in breakout mode, they operate as 4 completely independent ports

 

[gregsachs]

you can use however many you want, even just one. When QSFP+ switch ports operate in breakout mode, they operate as 4 completely independent ports

Note that the opposite does not appear to be true for NICS...

 

[fohdeesha]

Note that the opposite does not appear to be true for NICS...

I don't know of any 40gbE NICs that even support breakout in the first place

 

[Bjorn Smith]

Ok, cool thanks - just what I wanted to hear.

Naturally I lose the ability to control VLAN's etc per "cable" I guess on the QSFP+ side, since the switch still only have one port.

I guess I just need to buy a cable and find out how my Mellanox SX6018 reacts - it would be great if it magically transformed the one port into 4 different ports you can manage

 

[Rand__]

No, the port will be divided into 4 (or 2 depending on split width) sub ports which can be individually managed.
Note not all ports can be split on the 6018

 

[Bjorn Smith]

OK, cool -just looked it up and it seems like 12 ports can be split - so the 18 ports can be turned into 56 ports - thats pretty nice Now I am even more happy with my mellanox switch