Having said that, commercial solutions usually offer a different set of functionalities
with respect to Carrier Ethernet; some may, for instance, only be able to provide
E-LINE capabilities, while others may provide both but be distance-limited. Some may offer
a limited amount of carrier-class attributes but this may be an acceptable solution in a
specific context (e.g., the lack of a very robust fault-tolerant solution may be acceptable to
a small Service Provider offering Ethernet-based Internet access at very low prices6).
Thus, the landscape of commercially deployed Carrier Ethernet solutions is fairly
broad, fragmented, and ultimately a source of confusion as far as understanding how
the specific solutions fit.
6 This presupposes, realistically, that cheap Internet access service does not offer a 7 ?— 24 up time; and an
occasional failure is tolerated by the end user.
Figure 4.2 The landscape of solutions for delivering Carrier Ethernet
OSI Layers
13
12 11 10
6 5 8
7 15
14
9
Wired Wireless
FSO
WiMax PON
MPLS Bridging/
Switching
RPR SONET TDM
HFC
Note: The circled numbers indicate the corresponding chapters that discuss the topic.
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