Another benefit of using MPLS to offer Ethernet services, as noted above, is the ease
with which services can be offered over the wide area. Many providers of business
Ethernet services offer a mix of intra-metro and inter-metro services (in addition to using
their Ethernet platforms to provide access to the Internet and to IP-VPN platforms).
Figure 14.11 MPLS PE devices at the Metro Ethernet core
MPLS core
(to other metros)
P
PE
464 Chapter 14
Most incumbent carriers also offer Business Ethernet services now, using a variety
of different networking technologies. In some cases, Business Ethernet services have
been offered more or less piecemeal, layered on existing SDH/SONET, ATM, or fibre
networks, whereas in others, dedicated Layer 2 or MPLS-based Ethernet platforms
have been deployed. The overall trend appears to be for carriers to migrate toward
single MPLS-based Ethernet platforms both to offer Business Ethernet services and to
backhaul consumer broadband traffic (see ???Triple Play Aggregation???).
The first generation of business Ethernet services were generally based on offering
point-to-point connections (or point-to-multipoint using VLANs at the central site) and
on selling bandwidth by the megabit on an uncontended basis (though oversubscription
was sometimes used to increase network efficiency).
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