For a connection between two devices on the same rack: Is there any notable difference or advantage between using 1Gb SFPs and using Gb Ethernet ports? (making a bonding/etherchannel).

I know for large ammount of ports the energy consumption might be a variable to consider, or long distances. Buts just for one connection is there anything else to consider that might make it the best option?

thanks for reading

3 Answers 3


No difference in performance. Two SFPs and a fiber patch are more expensive than a Cat-6 jumper, but you already knew that.


Totally agreeing with Ron's answer for gigabit Ethernet.

It becomes quite different with 10G Ethernet, where twisted pair requires significantly more power and increases latency in comparison to DACs or fiber connections. Beyond 10G, twisted-pair cabling becomes largely impractical even.


At a basic level: no difference, just as Ron and Zac67 say: From the perspective "focused on the cable": no difference.

Buts just for one connection is there anything else to consider that might make it the best option?

There might be: Internal device architecture. Devices that come with both RJ45 ports and SFP slots might have either set of ports wired differently internally, offering different capabilities and characteristics.

For example: (thinking of a device like the Cisco 890 or the 1100 series routers)

A block of 4 or 8 RJ45 ports are connected to the devices switching ASIC, and they share one internal backplane uplink to the device's routing engine. At Layer 2, they're quite decent switching ports and can L2-forward at line rate, but they're limited in features (QoS, NAT, etc).

The SFP on the other hand slots/ports might be directly attached to the routing/L3 engine, might be based on quite different ethernet hardware (more like a computer's NIC) and while they have advanced features (QoS, NAT etc), throughput might be limited by the L3 engine's performance.

In short: Be sure to understand if and how the devices in question have different features/capabilities between their RJ45 and SFP ports.

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