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25GB Connectivity issue between S3260 server and Nexus switches

Dear Support,

 

I have a s3260 server (UCSS-S3260) with a network card (UCSC-PCIE-C25Q-04 = Cisco UCS VIC 1455 Quad Port 10/25G SFP28 CNA PCIE) that is installed on the SIOC (UCS-S3260-PCISIOC) card in the server.

 

This server is connected to a nexus switch (N9K-C93180YC-EX= Nexus 9300 with 48p 10/25G SFP+ and 6p 100G QSFP28) with a cable of 25GB (SFP-H25G-CU3M=  25GBASE-CU SFP28 Cable 3 Meter).

 

The os on the server is windows 2019 standard.

 

Mu issue is that the ports are not coming UP on the server . However the server can see the card and if I put a link of 10 GB it works properly.

 

I did firmware Upgrade for the server and Bios upgrade and I updates the driver ,etc… but still facing the same issue.

 

Your support is highly appreciated in order to let the connectivity between the server and the nexus switches become UP.

 

2 ACCEPTED SOLUTIONS

Accepted Solutions
Cisco Employee

Re: 25GB Connectivity issue between S3260 server and Nexus switches

Greetings.

Probably has to do with FEC mode negotiation (or the lack of).

Try changing the FEC mode on the VIC adapter to FC-FEC (cl74) and confirm the N9k port matches.

 

Kirk...

 

fec-settings.JPG

Cisco Employee

Re: 25GB Connectivity issue between S3260 server and Nexus switches

Hi,

 

May be issue with Forward Error Correction (FEC) Mode.

The "Auto" FEC mode on the VIC 1400 adapters defaults to cl91 (RS-FEC) instead of actually negotiating with the switch.

 

Consider making below changes in adapter on server side.

 

Server# scope chassis

Server /chassis # scope adapter 1

Server /chassis/adapter # scope ext-eth-if 1

Server /chassis/adapter/ext-eth-if # set admin-fec-mode cl74

Server /chassis/adapter/ext-eth-if* # commit

Changes to the network settings will be applied immediately.

You may lose connectivity to the Cisco IMC and may have to log in again.

Do you wish to continue? [y/N] y

 

 

2 REPLIES 2
Cisco Employee

Re: 25GB Connectivity issue between S3260 server and Nexus switches

Greetings.

Probably has to do with FEC mode negotiation (or the lack of).

Try changing the FEC mode on the VIC adapter to FC-FEC (cl74) and confirm the N9k port matches.

 

Kirk...

 

fec-settings.JPG

Cisco Employee

Re: 25GB Connectivity issue between S3260 server and Nexus switches

Hi,

 

May be issue with Forward Error Correction (FEC) Mode.

The "Auto" FEC mode on the VIC 1400 adapters defaults to cl91 (RS-FEC) instead of actually negotiating with the switch.

 

Consider making below changes in adapter on server side.

 

Server# scope chassis

Server /chassis # scope adapter 1

Server /chassis/adapter # scope ext-eth-if 1

Server /chassis/adapter/ext-eth-if # set admin-fec-mode cl74

Server /chassis/adapter/ext-eth-if* # commit

Changes to the network settings will be applied immediately.

You may lose connectivity to the Cisco IMC and may have to log in again.

Do you wish to continue? [y/N] y

 

 

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