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New Member

cabling IOM / FI


I begin to work for a new customer. This customer have a UCS domaine since 2012 with 2 chassis.

By looking, i have notice that the chassis 2 is connect to FI as follow :

IOM-A (left when we look from the behind side) to FI-B

IOM-B (right) to FI-A

The chassis 1 is connectd as usually IOM-A (left) to FI-A and IOM-B (right) to FI-B.

RMD-UCS-FABA-B(nxos)# show interface fex-fabric

     Fabric     Fabric       Fex               FEX          

Fex Port     Port State   Uplink   Model         Serial  


2   Eth1/2       Active     1         N20-C6508 FCH16057DTM

2   Eth1/4       Active     2         N20-C6508 FCH16057DTM

2   Eth1/6       Active     3         N20-C6508 FCH16057DTM

2   Eth1/8       Active     4         N20-C6508 FCH16057DTM

1   Eth1/18       Active     1         N20-C6508 FCH160370RL

1   Eth1/20       Active     2         N20-C6508 FCH160370RL

1   Eth1/22       Active     3         N20-C6508 FCH160370RL

1   Eth1/24       Active     4         N20-C6508 FCH160370RL


RMD-UCS-FABA-A(nxos)# show interface fex-fabric

     Fabric     Fabric       Fex               FEX          

Fex Port     Port State   Uplink   Model         Serial  


1   Eth1/2       Active     1         N20-C6508 FCH160578UZ

1   Eth1/4       Active     2         N20-C6508 FCH160578UZ

1   Eth1/6       Active     3         N20-C6508 FCH160578UZ

1   Eth1/8       Active     4         N20-C6508 FCH160578UZ

2   Eth1/18       Active     1         N20-C6508 FCH160579A5

2   Eth1/20       Active     2         N20-C6508 FCH160579A5

2   Eth1/22       Active     3         N20-C6508 FCH160579A5

2   Eth1/24       Active     4         N20-C6508 FCH160579A5


but when we look the VIF, it seems not right.

Two questions :

- this cabling is-it possible or not ? (the server do work)

- i can find any raison to do that ?

Many thanks for your answers and your point of view about that cable.


Cisco Employee

cabling IOM / FI

IT doesn't matter which IOM connects to which FI, as long as it's a 1:1 connection. 

I'm not sure I understand why you think there is an issue.


New Member

cabling IOM / FI

thx Robert, for your feedback.

The VIF is very confusing, of my oint of view. Tomorrow, the debug will be more hard, it seems to me.

but it is allowed to do the cabling, it is ok.

cabling IOM / FI


As Robert specified there is no problem with the cabling as long as the relation is 1:1, all I have seen with customers and read in other questions is, users keeping the same cabling just to keep consistency and make easier possible future troubleshooting, otherwise that cabling is totally fine and supported.

What is the confusion with the VIFs?


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