# 25G SFP28 NIC and 25G SFP Adapter

My company recently purchased some Dell R740's with 2 Dual Port 25G SFP28 NIC's (Broadcom 57414) and wants to hook them up to an Arista 25G switch. We have two types of SFP adapters from Arista: SFP-25G-SR and SFP-10G-SR. We were hoping to get the servers running at 25G, but none of the 25G transceivers we have will operate at 25G when plugged into the R740.

Arista states in this document that the SFP-25G-SR connectors are the same as SFP28

Also, to keep the most basic configuration, there is a single fiber line running to each server, and each connected interface has only the following command:

switchport mode trunk


These are the configurations I've tried:

Server <--> Switch

Working Connections:

SFP-25G-SR <--> SFP-10G-SR

SFP-10G-SR <--> SFP-10G-SR

Unsuccessful Connections:

SFP-10G-SR <--> SFP-25G-SR

SFP-25G-SR <--> SFP-25G-SR

Just to ensure the switch and SFP adapters were not faulty, I plugged two of the 25G switches together with the 25G SFP's mentioned above and a link was established.

Are there any ideas as to why they aren't working as intended?

• You may want to share the exact interface configurations. – Teun Vink Jan 4 '18 at 19:54
• Did the answer help you? You should accept the answer if it helped you to a solution. :-) – user36472 Feb 4 '18 at 10:06
• Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer. – Ron Maupin Feb 21 '18 at 18:20