<networking> 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.
<networking> (LSR) A device that typically resides somewhere
in the middle of a network and is capable of forwarding
datagrams based upon a label. In many cases, especially
early versions of MPLS networks, a LSR will typically be a
modified ATM switch that forwards datagrams based upon a
label in the VPI/VCI field.
