While the service provider may have enough
266 Chapter 10
network bandwidth for large customer data payloads, the bandwidth is not likely to
be in a single contiguous channel. In this case, the simple mapping approach just described
will not work.
It is obvious that a more sophisticated approach??”one that allows for the efficient
mapping of any payload into existing TDM transmission capacity??”must be created
to handle fast-growing Ethernet transport needs. The technology must decouple the
payload to be carried from the transmission system used to carry that payload. This
technology must also apply to multiple bit rates, formats, or applications.
Some of the requirements include the following:
?– Combine bandwidth across multiple, physically diverse transmission channels, independent
of the data rate and transport protocol.
?– Allow multiple clients, possibly of different formats, to share the concatenated
bandwidth simultaneously regardless of client format and data rate.
?– Provide consistent client protection against channel failures due to transmission
impairments, such as arrival time variation excessive bit error rate.
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