Netflow for this setup?

[devils_advocate]

Hello

Assuming the following setup, how would I configure Netflow and on which interface?

Switch 1 > Trunk > Switch 2

Switch 1 is a multilayer switch, several Vlans terminating and it has a default route of a firewall of a device connected to switch 2.

Default gateways for all local vlans are on Switch 1.
Switch 1 as a default route of 1.1.1.1.
1.1.1.1 is part of Vlan50 which is a Vlan trunked between Switch 1 and Switch 2.
1.1.1.1 is a firewall connected to switch 2.

Struggling to work out if I need L2 netflow (due to Trunk port) or Layer 3 and on which interface I enable it?

I want all traffic going from local Vlans on switch 1 towards the firewall?

Edit - switch 1 runs IOS-XE and Switch 2 NX-OS. 

Ta :)

[rasmus.elmholt]

Are you sure the switches you have support NetFlow?

Check the feature navigator.

NX-OS http://www.cisco.com/c/en/us/support/docs/switches/nexus-7000-series-switches/112213-netflow-nexus7000-nsox-configex.html

IOS-XE: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/3se/flexible_netflow/configuration_guide/b_fnf_3se_3850_cg/b_fnf_3se_3850_cg_chapter_010.html

[devils_advocate]

They do indeed support it.

thanks