Hi,
Once you pin a TEP to an interface and select this policy. When you receive traffic the source port of the traffic is determined and based on this the traffic is balanced across the TEPs to evenly distribute the load. This behaviour changes depending on what algorithm you use (Load balance source mac, failover or even more if you are talking about traditional networks).
Be very mindful if you ever choose load balance source mac, as it determines the source based on the received MAC address, sometimes not helpful.
Cheers
Shashank Mohan
VCIX-NV 2022 | VCP-DCV2019 | CCNP Specialist
https://lab2prod.com.au
LinkedIn https://www.linkedin.com/in/shankmohan/
Twitter @ShankMohan
Author of NSX-T Logical Routing: https://link.springer.com/book/10.1007/978-1-4842-7458-3