Hello Arup,
you need a modern classless IGP like OSPF, IS-IS or EIGRP (but this doesn't support MPLS Traffic Eng.)
you need to allocate loopbacks interfaces on all routers use /32 (255.255.255.255) masks they will represent each node. loopback ip addresses must be unique.
advertise the loopbacks ip addresses in your IGP.
You need to enable CEF
ip cef
mpls ip
mpls label protocol ldp
mpls router-id loop1 force
on each interface you want to configure for MPLS switching (backbone facing ones)
int type x/y
mpls ip
be aware that if you plan to delivery MPLS L3 VPN services you need to take care of mtu problems.
on some older IOS releases you need to use
tag-switching instead of mpls in the commands.
A reference can be the following:
http://www.cisco.com/en/US/docs/routers/7600/ios/12.2SR/configuration/guide/pfc3mpls.html
this is for C7600 but provides info for all platforms
Hope to help
Giuseppe
