VeEX UX400, Руководство пользователя

Страница: 167 / 209

V5 [VT Path]: Path signal label
Program the TX and RX label by editing the hexadecimal value or by using the convenient drop-down menu selection
For the RX label, you can enable or disable the Payload Mismatch (PLM) Alarm
Payload Label RX VT
Go back to top Go back to TOC
7.4.6 APS Tasks
APS Timing
This function measures the Automatic Protection Switching (APS) limits of the network. APS applies only to the Multiplex sections of a SONET network and enables network
elements to re-route traffic to a backup circuit in the event of network failure or problems. The protection mechanism is coordinated by the K1 and K2 bytes in the Multiplexer
Section Overhead.
APS Standards
The principles and protocols of APS in SONET networks are defined in ITU-T G.783 and G.841 and Bellcore GR-253 recommendations for Linear and Ring network
architectures respectively. According to these recommendations, the re-routing of the signal has to occur within 50ms. Protection switching is initiated as a result of
one of the following conditions:
“Hard” Failure (SF) condition – Loss of Signal (LOS), MS-AIS, BER >1 x 10
-3
.
“Soft” Failure (SD) condition – Signal degradation when BER exceeds a predetermined threshold. Normally over a provisioned range of 1 x 10
-5
to 1 x 10
-9
.
Tap the APS Tasks icon to display the APS testing screens shown below.
Sensor:
Select the trigger that will initiate the APS measurement.
The selections are: LOS, LOF, SONET FAS, S-BIP, AIS-L, RDI-L, REI-L, L-BIP, AIS-P, LOP-P, P-BIP, RDI-P, REI-P, LSS and None
Switch Time Limit:
Configurable in the range from 15ms to 200ms.
Typically 50ms according to ITU-T recommendations.
Gate Time
: Configurable in the range from 200ms to 4 seconds.
Used to measure total service disruption when multiple switches or micro interrupts occur.
Repeat
: ON/OFF
Configurable to measure on a continuous basis.
Start
: Press to begin the test.
APS Timing Setup
UX400 10G e-Manual D07-00-058P RevA00 Page 167 of 209