Showing results for 
Search instead for 
Did you mean: 

40Gbps QSFP vs 4x 10Gbps SFP+ port channel


I am learning about 40Gbps QSFP; however, it says channels, and 4x 10Gbps channels. Does this mean that it is a type of Port-channel or load balancing and where each session or stream is only going to get 10Gbps?


I need to connect a 2k to a 5k, which I have options to use QSFP or SFP+.  I am just not sure how the 40Gbps is true 40Gbps with 4x 10Gbps links.


Thank you


4 Replies 4

Joseph W. Doherty
Hall of Fame Master Hall of Fame Master
Hall of Fame Master

I believe (?) the way it works if you have the QSFP on both ends it uses the 4 10g links like an IMUX.  I.e. you should be able to send even a single flow at 40g.

I also believe (?) of the QSFP modules support 10g breakout, i.e. they can connect to "ordinary" 10g ports on the other side.  In such cases, the QSFP would appear to be 4 10g links.  (The advantage of this would be port density on the QSFP side.)

BTW, I'm not an expert in optics, but I see no one else has tried to answer your question, yet.

Mark Pace Balzan


Not an optics expert myself either but I have setup 40g as 4x10g and in such case they are four independent 10g interfaces with no relationship to each other. 

If you use it as 1x40g then thats what you get 40g of traffic. Internally it does some multiplexing to achieve 40G but this is transparent to you, its not a port channel  neither do you need to configure anything related to port channel 


Hope this helps 



Sorry for not replying sooner, I was ill and took time off.


Thank you both for your help. I have a TAC ticket open and will append the notes. I am not fiber expert, but trying to learn.


Thank you again.


You should look into the Cisco 40G BiDi SFP’s.  You only need 2-Strands of fiber to achieve 40G. 


Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:

Recognize Your Peers