Fibre Channel Forwarding between devices behind single NPIV port

[StroganovVG]

How does Fibre Channel switch with NPIV enabled port operates, when two devices behind the single NPIV port want to communicate with each other?

e.g. Ethernet switch, would just drop frames, if destination mac address in a frame arrived on physical interface, which already learnt this mac address to be reachable via the same port. But FC, is more complicated than Ethernet, there is much more control-plane mechanisms (flogi,plogi, what else?). So I haven't found yet, how FC switch would behave in this case.

Actually, the question has arrised, because we have a problem, with Cisco Nexus 93180yc-fx switches. Our small lab design is: NPV enabled Edge (93180yc-fx) - Core with NPIV enabled ports (nexus 5548). We want 93180yc-fx to forward traffic between targets and initiators connected to it (I know, the actual forwarding take place on Core in this case), but it wouldn't. But when we connect target to Core directly, everything works just fine... So I need an explanation, on why is it behaving in such a manner.

[jihicks]

I am replying to this post so that everyone can see the resolution.

Host and storage were both on the Nexus 9K ( NPV ) connected to an Nexus 5K ( NPIV ).

Storage was connected at 8Gb which is not supported on the Nexus 9K.

Please see "FC NPV Guidelines and Limitations" here:

Cisco Nexus 9000 Series NX-OS FC NPV Configuration Guide

The N9K is not capable of using fill pattern arb(FF) for fill words, so 8G speed is not supported for server and target interfaces.  Set these to either 4Gb or 16Gb, since these use fill pattern IDLE for fill words. 

If you want to use 8Gb links from the N9K to a core NPIV switch, configure the interfaces on the core NPIV switch connected to the N9K to use fill pattern IDLE for 8Gb. This can be done on Cisco MDS and N5K switches with the interface configuration command "switchport fill-pattern IDLE speed 8000" on the NPIV switch.

You should not put devices that need to communicate with each other on the same NPV switch, as they can not directly communicate with each other without going through the NPIV switch.   This is contrary to the design of NPV switches and will likely not work,  as all traffic between the devices will have to traverse the links to the NPIV switch twice.