This far exceeds the scalability of
other multiplexing technologies such as VLANs (limited by a 12-bit field) and RPR
(limited to the stations on a single ring). Moreover, MPLS provides a way to ???stack???
multiple MPLS labels, making MPLS scalability practically unlimited??”and helping
to enable another key attribute (scalability) of Carrier Ethernet.
?– MPLS provides a connection-oriented packet transport layer in between the
Ethernet and SONET layers. This layer provides the bandwidth efficiency and
flexibility of a packet multiplexing layer, while enabling many features, for example
hard QoS, rapid protection, and OAM features, that are difficult or even
impossible with connectionless technologies such as Ethernet bridging. This allows
EoS networks to use Ethernet bridging as a service-level function (usually near the
edges of the network), with MPLS providing efficient, manageable, and resilient
transport in between.
?– Pseudowires enable MPLS to provide a common data transport for Ethernet and
other data services, such as ATM, frame relay, and IP. This enables the SONET
network to carry these services more cost-effectively.
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