Nexus 3k high availability requirements

[SaifH]

Hi,

I would like to know what are the requirments to do high availablity for Nexus 3k?

Are both devices needs to be same IOS version and same Model? 

Should the Fex number match on both devices? and is there something else should match on them?

Thanks,

[MHM Cisco World]

you need license if below not run 
vpc feature 
lacp feature  
inter-vlan feature 
then config vPC between two N3K sw

[SaifH]

what about fex numbers? does the port count should match on both devices?

[MHM Cisco World]

port count you meaning that each have different port number, this will not effect vPC between two NSK 
but can I know the NSK platform number exactly  and card number in both ?