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Nexus 5000 FCoE General Question


Hi there,

imagine the following (simple) configuration:

- Server with dual port CNA connected to a N5k

- CNA port 1 connected to interface Ethernet 1/9

- CNA port 2 connected to interface Ethernet 1/10

- CNA FCoE MAC port 1 bound to vfc 109

- CNA FCoE MAC port 2 bound to vfc 110

- CNA NIC ports as well as the corresponding connected Nexus ports e1/9 & e1/10

  are configured as LACP 802.3ad port-channel

- Storage subsystem connect to N5k native FC port

Coming from the Ethernet world one could say how can this work because the LAG hash makes the traffic flow undeterministic but

the N5k is a FCF and is therefore FCoe/FC traffic aware. For example you won't find the FCoE MACs vound to the vFCs in the MAC-address-table.

It separates the FCoE/FC wordl from the Ethernet world. So a FCoE multipathing setup with a underlying LAGs/port-channels isn't a problem because Nexus takes care of this scenario. (As far as I know Brocade does not support that - does that mean an FCF switch is not equal an FCF?)

But what I am curious about to know is how that exactly works internally.

More precise, can someone tell me a command how to find out the physical port where the Nexus learnt the FCoE MAC which is bound to a vFC?

The Nexus must have this information somewhere because otherwise the scenario described above wouldn't work.

Please let me know if you have any hints.

Thx and have a nice weekend!

2 Replies 2


Nexus 5000 does not learn Fabric provided MAC address (FPMA) and store into the MAC address table because there is no ethernet frame forwarding happens to this mac address(frame with DEST_MAC = FPMA). Only FCoE and/or FIP frames are forwarded to that MAC address and rule for FPMA is first 24 bits is FC-OUI and last 24 bits is your FC-ID (8bits domain 8 bits area and 8 bits port). So you can easily find FPMA.


show fcoe command can also give you more details.

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