I noticed the game seems quite hell bent on NAT (Like MW2)
Off Support ubi site:
Uplay PC:
TCP: 80, 443
Game Ports:
3074 UDP
6015 UDP
This, we were having problems joining games and grouping up and turns out my Nat type was listed as moderate (Press F10 and it tells you). Forwarded ports and restarted router and it listed my NAT as open. Been a lot more stable since.