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10G SFP for Nexus 93180YC-EX Chassis

We just purchased a Synology NAS, model RS4017xs+, and will be connected to our Cisco Nexus 93180-YC-EX switches. What kind of 10G SFP I should purchase for the Nexus? I got the data sheet from Cisco, but there are over a dozens to choose from, so I'm a bit confused. Any input will be greatly appreciated. TIA.
Networking Hardware-OtherCiscoSwitches / Hubs

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Predrag Jovic

8/22/2022 - Mon
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Predrag Jovic

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Tightwad

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Thank you so much for your info, Predrag Jovic. I will find out what we purchased from Synology. Judging from everything that I've read on the Cisco website, I should be able to use SFP-10G-SR module on the Nexus. If the NICs from the Synology have the SFP+ connector, then I can use the Cisco SFP+ Twinax copper cables, otherwise, I will have to order fiber patch cable with SFP+ connector on one end, and LC connector on the other, is that correct?
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Predrag Jovic

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Yes, the distance is definitely less than 10m, so MM solution will work. We are currently running NX-OS 703I5.1, so I am hoping we can use SFP+ Twinax copper cables as the cost is lower. I have another question, what is the difference between Cisco SFP+ Twinax copper cables and Cisco SFP+ Active optical cables? What's the use case or why choose one over the other?
Predrag Jovic

I never checked what is the difference between those two and when to use it. I always used just Cisco SFP+ Twinax copper cables. :)
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Tightwad

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Thank you atlas_shuddered for the explanations. I had a hard time trying to find out the difference between the two and the use case.
Predrag Jovic

Explanation does not fit to explanations that I read yesterday from cable manufacturers. For example this one below (I read few more with similar explanations).
:)
What's the Difference between Active and Passive Twinax Cable?
Active twinax cable


An active twinax cable carries a 10 Gig Ethernet signal over long lengths (5m or more, like XFP active cable) of copper with the use of signal boosting technology. Passive copper cables contain no electrical components. Active copper cables contain electrical components in the connectors that boost signal levels. This makes active copper cables slightly more expensive than passive copper cables; however, they can connect the Converged Network Adapter (CNA) to a top-of-the-rack switch over longer distances than passive copper cables.

How to distinguish active or passive twinax cable

There isn't a truly visual way to tell the difference between active and passive twin-ax cables. Active or passive twin-ax cable assembly and connects directly into an SFP+ housing. The active twin-ax cable has active electronic components in the SFP+ housing to improve the signal quality; the passive twin-ax cable is just a straight “wire” and contains no active components. Generally twin-ax cables that are less than 5 meters in length are active and greater than 5 meters in length are passive but this is a general rule of thumb and will vary from vendor to vendor.  The connectors are the same and the cable jackets are identical. So how do you tell? Most manufacturers will have some sort of marking on the cable connector head which will identify the cable as active or passive. It is hard to tell by simply looking at it.

How to choose passive or active twinax cable

With all cables, length and signal strength are always something to look into. For shorter distances it is common practice to use passive cables, they are rated for ranges up to 5m and provide a good working solutions at a great cost. SFP+ DAC (Direct Attach Copper) passive twinax cable is suitable for very short distances transmission and offers a highly cost-effective and low power solution to connect within racks and across adjacent racks. SFP+ twinax passive cable allows for a serial data transmission up to 10.3Gb/s, which is a low cost choice for very short reach applications of 10GbE or 1-8G Fiber Channel.


When the distance between connection points that exceed 5m, it is highly recommended to use active cables to ensure signal is transferred all the way through. The cost may be a bit higher, but the signal is improved and gives peace of mind by creating a trustworthy connection.
This matches with Cisco's compatibility matrix for 10Gb SFPs - passive cables length is up to 5 meters, and active cables length are up to 10m.
SFP-H10GB-CU - passive cables (up to 5 meters)
SFP-H10GB-ACU - active cables (up to 10 meters)
SFP-10G-AOC - active cables (up to 10 meters)