Fcoe load-balance between N7k storage VDc and N5k

[bchintak]

If I don't change any port-channel load-balancing mechanisms in N7k and N5k (Assuming sid/did/oxid is default in N7k and sid/did is default in N5k), what storage traffic follows in both directions

[Philip D'Ath]

I don't know the answer, but I found this:

http://www.cisco.com/c/en/us/support/docs/switches/nexus-5000-series-switches/116298-configure-nexus-00.html

On Nexus 7000, by default the source-destination-oxid load balancing mechanism is used for FCoE traffic.

[bchintak]

Yes that's correct. I have mentioned the same in my question.

sid/did/oxid is default in N7k and sid/did is default in N5k
But my question is what could be the impact if we have connected N7k and N5k through FCoE (without changing any load-balancing mechanisms)
Will traffic from N5k -->N7k uses sid/did/oxid or sid/did

and traffic from N7k-->N5k used sid/did/oxid or sid/did

[Philip D'Ath]

I would expect the default for the platform would remain unchanged regardless of what is plugged in.  It couldn't suddenly changed based on what is plugged in.  It is not a negotiated value to the best of my knowledge, so how could it change.

So I think it should be:

N7k-->N5k will be sid/did/oxid

N5k -->N7k will be sid/did.

[Akheel Kapoor]

“On Nexus 5500 the default load balancing mechanism on the LACP port-channel for FCoE traffic is "source-destination". In this default state, all the FCoE traffic takes the same link in the port-channel when the Nexus 5500 forwards frames over FCoE VE ports. In order to enable all links to be used in the port-channel for FCoE traffic, enter the port-channel load-balance ethernet source-dest-port command to configure Nexus 5500 "port-channel load balancing" to "source-dest-port". With this configuration "source-destination-oxid" load balancing is used for FCoE traffic.”

[bchintak]

As far as I know both N7k and N5k  Fcoe load balancing mechanism depends on underlying ethernet port-channel load balancing mechanism. Can you please provide the reference for your statement.

[Akheel Kapoor]

This could be the behaviour  

1. Nexus 7K : Load balancing is control by vsan load balancing and default behaviour is src/dst/ox-id (load balance to all links).

         2. Nexus 5K : Load balancing is control by port-channel load balancing and default behaviour is src-dst-ip (only utilize 1 link).

[sbhadrav@cisco.com]

I don't think that there is a FCoE NPV license, resp. a NX-OS command "feature fcoe-npv" for N7K; therefore in the storage VDC, you do NPIV, not NPV.
It is common, to use the N7k in the access, connecting hosts with FCoE:
FCoE on the Nexus 7000 also supports a unique capability that enables interfaces to be shared between two VDCs. This enables the Nexus 7000 to be used in the access layer of networks where servers connect to the switch and use FCoE. A shared interface enables FCoE traffic to be segmented into the Storage VDC at the edge of the network. When an interface is shared between two VDCs, a few rules must be followed:
Interfaces can be shared only between one Ethernet VDC and one Storage VDC.
Interfaces to be shared must be configured as 802.1Q trunks in the Ethernet VDC.
Interfaces may be shared only from the Ethernet VDC that allocated VLANs to the Storage VDC.
The Ethernet VDC “owns” the physical interface. If the interface is admin down in the Ethernet VDC, it will be admin down in the Storage VDC.
All ports that have a common ASIC must be allocated as shared interfaces. This is done in groups of two on the F1 modules and groups of four on F2/F2e modules.