VeEX UX400, User Manual

Page: 187 / 209

TCM Standards
The Tandem paths are defined in ITU recommendation G.707 Annex D and Annex E
G.707 Annex D for VC4 and VC3
G.707 Annex E for VC2 and VC1
G.707 defines a tandem connection source and sink and describes the responses of each when defect (alarm) and error conditions are detected
Tandem connection maintenance signals are carried in:
N1 byte for VC4 and VC3
N2 byte for VC2 and VC
These two bytes are structured similarly, but their functions are not identical
Go back to top Go back to TOC
7.5.8 Tributary Scan
This SDH/SONET monitoring function requires VC12/VC11 or VT-1.5/VT-2 mapping and allows for a quick check of the signal structure, trace identifier, and the payload.
An important part of any Add Drop Multiplexer (ADM) installation process is the verification of the path routing. Considering that an STM-1/STS-3 contains 63 x VC-12’s and
a STM-4/STS-48 contains 252 x VC-12’s, checking each path manually can be very time consuming.
The unit automatically performs a sequential BER test on each SDH/SONET tributary (C12 channel) - mapping can be either via AU-4 or AU-3 to assess the health of each
channel. The unit checks for error, alarms or status indicators in each channel of the received signal., the SDH structure, and if a test pattern is found in the payload,
matching the unit’s settings, pattern sync is achieved and a quick BER test is performed for synchronization of the selected test pattern in all channels.
The result for each channel is entered in a table:
K.L.M.:
Shows the ITU-T Tributary numbering scheme
Report:
Summary assessment of each channel
Pass (OK)
if the payload contains a test sequence (pattern) matching the one set in the Setup menu.
BIT
if a test pattern was found and bit errors were detected
LSS (Live)
if no test pattern was found inside the payload
Any
SDH/SONET error, alarm or status
indicators detected on each tributary
J2 trace:
Corresponds to the VT or VC trace identifier being transmitted in each channel
Payload Label:
Corresponds to the V5 byte signal label being transmitted
Tapping on any of the table rows brings up an Event Details window.
Tributary Scan
UX400 10G e-Manual D07-00-058P RevA00 Page 187 of 209