I have one flat network with our data center and it is causing as a lot of issues, so i had to design a new network to separate the buildings from the data center, when I designed the new network i was thinking to cut off the old network but unfortunately some changes has been happened and we can't do that so we need to keep our IDF switches connected to the OLD MDF (N7K) that is connect to the DataCenter. Old design\ one flat network building connected the DC" N7K" and IDFs with one big subnet 10.100.x.x/16, the link between N7K and the IDF is trunk. new design\ Core switch connected via routed ports to the buildings MDF "Distribution layer" , And MDF connected trunk to the IDF , each building have there subnets and there is ospf routing enabled between the buildings.
Current situation now it's showing in the picture below. so the issue i am running to is