The company that I work for has a linked 3750 switch stack that was only working as a Layer 2 switch and sent all Layer 3 to a external 3745 router via sub-interfaces for inter-VLAN routing. Everything worked fine, but a little slow. The subnets were 172.16.x.x/22, 172.17.x.x/22 and 172.18.x.x/22. I added two new subnets (172.16.128.x/24 and 172.16.130.x/24) on the 3745 for eventual migration to shorten the subnets and move servers off of the user VLAN.
This weekend I turned on IP routing on the 3750 switch stack, moved the VLAN IP gateway addresses to VLAN interfaces on the switch stack and got them off of the sub-interfaces on the router, turned on EIGRP, changed the link to the external 3745 to a Layer 3 routed interface and made a few other minor tweaks and route changes to get the network up and running.
But one thing that I am noticing is that the VLAN interfaces are not showing the traffic that should be flowing over those interfaces. Everything is working and no users have reported issues, but I still cannot see traffic on the VLAN interface. Any ideas?