difference between vlan tag and routing instance

[inder]

Hi All,

Have a query on routing instance which i believe is used to select a
particular instance of routing table within a router (VRF) .

How is the routing instance different from vlan tag. I guess vlan tag
should operate at layer 2 (switches should understand) .

How is a particular routing table selected in a router ? From whre
does router get routing instance when traffic is initiated .

Thanks,
Inder