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Description
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Multiprotocol
Label Switching holds the promise of improving the performance,
reliability and service quality in packet-switched networks
by bringing many of the advantages of ATM networks to an arbitrary
switched link layer while avoiding many of their disadvantages.
MPLS achieves this by taking advantage of existing routing
protocols to set up virtual label-switched paths across a
set of label switching routers (LSRs)to identified destinations,
thus requiring a packet's layer 3 header to be interpreted
only at the ingress and egress of an MPLS switching domain.
This not only reduces the packet processing overhead but allows
for multiple paths to be established for a single destination,
allowing support for path protection, segregation of traffic
by class of service and traffic engineering.
Multiprotocol
Lambda Switching extends this paradigm into the optical domain
by using an extended MPLS (or MPLS-like) control plane to
control optical cross-connects. In effect instead of "route
once switch many" we then have "electrical once, optical many"
or "switch once, then transmit". Examination of this technique
shows that it can be used to create an optical packet core
network capable of delivering virtual services at OSI layers
1, 2 or 3 without the need for strict timing relationships
across the transmission core.
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