Anita,

MPLS was introduced in IOS 11.1(17)CT. Almost 10 years ago. Please refer the below info and URL for details.

New Features in Release 11.1(17)CT

In addition to the features in Release 11.1 CA and Release 11.1 CC, Release 11.1(17)CT supports the following new feature:

MPLS-MPLS is a novel approach to network layer packet forwarding. The two main components of the MPLS architecture are forwarding and control. Forwarding is accomplished using simple label-swapping techniques. Control results form the use of the existing network layer routing protocols plus mechanisms for binding and distributing tags. MPLS retains the scaling properties of IP and can help improve the scalability of IP networks.

http://www.cisco.com/en/US/docs/ios/11_1/release/notes/rn111ct.html#wp4671

Regards,

Arul

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