...................................................................................................................................................................................................................................

SDH provides for multiplexing of 2-Mbit/s (C-12) and 34-Mbit/s (C-3) signals into an

STM-1 frame.

Furthermore, multiplexing paths also exist for the SONET specific 1.5-Mbit/s, 6-Mbit/s

and 45-Mbit/s signals.

Process

The following describes the process for multiplexing a 2-Mbit/s signal. The

digital multiplexing" (p. A-11)

...................................................................................................................................................................................................

Input 2-Mbit/s tributary is mapped

• Each VC-12 carries a single 2-Mbit/s payload.

• The VC-12 is aligned into a Tributary Unit TU-2 using a TU pointer.

• Three TU-2 are then multiplexed into a Tributary Unit Group TUG-2.

• Seven TUG-2 are multiplexed into an TUG-3.

• Three TUG-3 are multiplexed into an VC-4.

• The VC-4 is aligned into an Administrative Unit AU-4 using a AU pointer.

• The AU-4 is mapped into an AUG which is then mapped into an STM-1 frame.

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After VCs are multiplexed into the STM-1 payload, the section overhead is added.

...................................................................................................................................................................................................

Scrambled STM-1 signal is transported to the optical stage.

A-14

illustrates the multiplexing process.

Alcatel-Lucent - Proprietary

See notice on first page

"SDH

365-312-801R7.2

Issue 3, May 2007

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