We have a router 2600 connected to a 3560 switch. On router side the link was configured as IP interface, on switch side was configured as trunk, 1q, native vlan 7XX.
Problem: switch can see the router in show CDP nei command, but the router can't. The input traffic in the router is 0.
After i changed the interface from trunk mode to access mode in the switch, it solved the problem.
Question: why is it? what blocked the traffic?