An attempt to combine the best attributes of layer two switching (as in atm and frame relay) with the best attributes of the layer three routing (as in ip).

The key concept in label switching is identifying and marking IP datagrams with labels and forwarding them to a modified switch or router, which then uses the labels to switch the datagrams through the network. The labels are created and assigned to IP datagrams based upon the information gathered from existing IP routing protocols.

Prior to the formation of the mpls Working Group in 1997, a number of vendors had announced and/or implemented proprietary label switching.