Administrative Unit - Siemens SRA 4 User Manual

1.4.1.5
Fig. 1.4
SRA 4 - 6/7/8/10/11/13 GHz (WB ODU) - UMN
911-381/02C0000 - Issue 3, July 2004
AU-4 Administrative unit
The administrative unit AU-4 is composed of two parts (Fig. 1.4):
– the overhead of the administrative unit (AUOH) which occupies the first 9 bytes of
the fourth line in the frame;
– the so-called payload which occupies the remaining 261x 9 bytes, divided into time
cells with a given address.
Composition of the AU-4
BYTES
AUOH
BYTES
9
Its overall transport capacity is:
C = 8 x (9 + 261 x 9) x 8 x 10
AU-4
a b
a) bits composing each single byte
b) bytes occupied by "AUOH"
c) bytes available for the payload
d) frequency of the STM-1 frame
9
TIME CELLS
AU-4
3
= 150.912 Mbit/sec
c d
1 - PRELIMINARY INFORMATION
BYTES
261
PAYLOAD
FRAME 125 µSEC
1-15