In IP MPLS, there are lables that a router generates as:
The MPLS label are of two types:
Explicit NULL(Head End router will Advertise Any Label)
Implicit NULL (Head End router will recieve NULL)
NULL (Head End router generates NULL)
My query is why there are requirements of 3 types of MPLS Labels in IP Network????? As in traffic forwarding phenomena there is no role of these Labels......
I don't have specific knowledge. I'll see if I can look it up. but, in general, remember that IP/MPLS is a kind of dedicated connection between two endpoints using a TCP/IP connection. It's not all that different from a VPN. In fact, I've seen documents that describe MPLS as a kind of VPN.
So the basic answer is that the labels are used to determine the endpoints of an MPLS connection.
I'll see if I can locate some additional specifics.