Traffic between different UCS fabric interconnect

[Jerome BERTHIER]

Hello

I'd like to confirm how traffic is handled between different UCS fabric interconnect.

By reading documentation, it seems that there is no traffic between FI switches :

If servers are bound to two different FI then the traffic is switched on LAN DC. Isn't it ?

Référence: https://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/unified-computing/whitepaper_c11-701962.html

I'm not in charge of computing servers system. So what I should exactly asked to be verified if I want to confirm the state on a specific DC UCS fabric ? The way that vnic are attached to IOM/IFM then to FI ?

Regards

[BrianSekleckiGE]

In the diagram above, the scenario would be extraordinarily unlikely as the standard is to have servers dual-homed to both FIs, or their connected FEX, in which case, the FEX or FI simply switches frames between ports; but, in the case of above --  two single-homed servers/hosts/blades -- without a FEX intermediate --  then yes, I suppose:

* (one of the two) external LAN switches would switch the frames first

* Resulting in the frame being forwarded it onto the adjacent FI.

* FI then switches it to the destination server.

[Jerome BERTHIER]

I'm a novice in UCS world.

If I'm right, one IOM is connected only on one FI (no cross connection to FI).

So what about vNics ? As server is dual homed using two IOM on two differents FI, are vNic mapped virtually to both IOM using load balancing or fail over ? Or are they pinned on a single IOM ?