AlwaysOn "We strongly recommend that you use the same network links"

"We strongly recommend that you use the same network links for communications between WSFC cluster members and communications between availability replicas. Using separate network links can cause unexpected behaviors if some of links fail (even intermittently)." - from "Prerequisites, Restrictions, and Recommendations for AlwaysOn Availability Groups (SQL Server)" http://technet.microsoft.com/en-us/library/ff878487.aspx

Question: 
If the data network on production site A and production site B have different Network Subnets, would this be considered as “same network links”? Or "same network links" has to be a stretched VLAN across different sites?  

Thanks... Alex Lam