Setup an access list on the router allowing them to communicate in the first place. If that is the 4500 set it up there.

In Cisco LAN switch environments, the native VLAN is typically untagged on 802.1Q trunk ports. This can lead to a security vulnerability in your network environment. It is a best practice to ...

In the IP based Ethernet networks, data and voice services are often transmitted simultaneously over the network. Voice traffic, in particular, requires a higher forwarding priority than data traffic.