InterVLAN

1.
To Ping an InterVLAN Sub Interface on a Router from a Switch,
or a connected PC, the related VLAN on the Switch has to be assigned
an IP address.Each VLAN on the switch has to be assigned an IP to be
able to Ping the Sub Interface on the Router or a connected PC.
This is because the PC's and subinterfaces are now segregated into
separate VLAN's.

2.
Show command on a switch with InterVLAN on Router.
Switch#show cdp neighbor
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone
Device ID Local Intrfce Holdtme Capability Platform Port ID
Router Gig 0/1 166 R C2900 Gig 0/0
Router Gig 0/1 166 R C2900 Gig 0/0.1
Router Gig 0/1 166 R C2900 Gig 0/0.2
Router Gig 0/1 166 R C2900 Gig 0/0.3
Switch#

3.
Native VLAN on an subinterface in the Router is for traffic which does
not belong to any VLAN.