Zte ZXA10 S300 - Switching of Reference Clock

ZXA10 S300 (V1.1) Integrated Access Service Dispatching Unit Technical Manual
46 Confidential and Proprietary Information of ZTE CORPORATION
 Recover timing from the signals of other tributaries like the
POS optical interface.
Switching of Reference Clock
The time for triggering the timing switching is within 10 second
after the loss of timing reference signal is detected or after AIS
signals occur at the timing interface.
The timing reference can be recovered both automatically and
manually. If there is a valid timing signal, the timing reference
will be recovered automatically within 10 ∼ 20 seconds.
The ZXA10 S300 can identify the label of the timing signal in the
SOH of the STM-N frame structure. It also supports the SSM
switching. Recommendation G.707 defines the SSM in the S1
byte of the multiplex section in the STM-N frame structure. In
the S1 byte, the 16 codes in Bit 5 ∼ Bit 8 stand for different
information, and indicates the quality level of the clock. See
Table 23.
TABLE 23 − SYNCHRONIZATION QUALITY STATUS MESSAGE
Serial
No.
Bit 5 ∼ Bit 8 of the
SOHS1 Byte
Type of SDH Synchronization
Quality Grade
0 0000 Quality unknown (current
synchronization network)
1 0001 Reserved
2 0010 Reference clock (G.811)
3 0011 Reserved
4 0100 Enhanced Grade-2 clock (G.812)
5 0101 Reserved
6 0110 Reserved
7 0111 Reserved
8 1000 Enhanced Grade-3 clock (G.812)
9 1001 Reserved
10 1010 Reserved
11 1011 SDH Equipment Clock (G.813)
12 1100 Reserved
13 1101 Reserved
14 1110 Reserved
15 1111 Not to be used for synchronization