While configuring sub-interface on 7600 a weird issue was observed. It was not allowing us to create vlan 1010 and throws a "errors % Configuring IP routing on a LAN subinterface is only allowed if that subinterface is already configured as part of an IEEE 802.10, IEEE 802.1Q,or ISL vLAN. To solve this issue we need to run the command "show vlan internal usuage" which tells about the status of vlan used by the module. If the vlan used for sub-interface is used here in that case need to check the vlan allocation policy. In our case the it is in ascending order and when we shifted it to decending order and a after soft reboot, the module takes the vlans from the higher series and freed the vlans like 1010.
Command for changing the vlan internal allocation policy is given below
vlan internal allocation policy descending
And here is the rest of it.