IEEE
802.1ag and ITU-T Y.1731 define a means of determining, reporting, and diagnosing the
health of a Carrier Ethernet network using only Ethernet frames, with no dependencies on
the underlying technologies. Thus, Ethernet CFM/OAM can be very useful to a customer
or a provider, even if bridges are not employed at all in providing the Carrier Ethernet
service. (For that matter, CFM can be of considerable use in an enterprise network.)
Drivers for This Solution
As implied by the layout of the preceding section, ???Technology Description,??? the development
of the Ethernet bridging solution for Carrier Ethernet has been, for the most
part, a straightforward process of development from enterprise scale networks. This
process has been driven by
?– The observation that the VLANs of IEEE Std 802.1Q-1995, widely deployed in the
enterprise space, are equivalent to provider services.
?– The recognition by IEEE 802.1 of economic considerations??“namely, the assumption
by 802.1 that the bridge will become obsolete the instant any other packet technology
with equivalent functionality can undercut its price.
?– The obvious fact (obvious, at least, to the bridging community) that since the behavior
of bridges define ???Ethernet service,??? they have a significant role to play in
providing such services to customers.
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