Hi Bab L,
I have read your question carefully,Here is the solution that you can implement on 3850 switch
You can use route map along with weight metrics say as 200 on 3850 switch such a way that all traffic from azure towardsWAN should flow from 3850 switch
1. Create access list for WAN network access-list 1 permit 10.18.29.16 0.0.0.7
2. Create (1).route map xyz permit 10 (2). match address 1 (3). Set weight 2000
4. Create another route map so as to drop other traffic.(Route-map xyz permit 20)
5. Now add filter so as to where to apply (1).router bgp *** neighbor 10.29.18.2 remote-as **** in
Regards,
Lohit Lende
Spooster IT Services.