In a label switch communications network, a third level of label is employed
in
conjunction with a dynamic multiplex constraint-based routed label switched path
(CR-LSP) in order to achieve implicit switching at nodes within the network. Implicit
switching occurs when a switching function takes place at a node without the need
for any control function being required at that node. A three-layer label stack
provided at the edge of the network achieves end-to-end connection oriented behaviour
with guaranteed Quality of Service. The use of the three-layer label stack concentrates
the control of the network to the two edges of the network and a single central
switching stage of the network.
