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Matrix Switch test tools 91
Model 6511RC User Manual 5 • Troubleshooting and maintenance
Sections and paths
Between a pair of SDH multiplexers, an SDH circuit may comprise multiple cable segments connected by
intermediate devices such as signal repeaters and add-drop multiplexers (see figure 66). A cable segment with a
regenerator at one or both endpoints is called a section. A set of cable segments with an add-drop multiplexer at
one or both endpoints is called a line. An SDH circuit with full-service multiplexers at both endpoints is called
a path.
Figure 66. Section, path, and line within an SDH circuit
Section trace
The section trace function verifies section connectivity between the two section-terminating nodes.Two SDH
section-terminating devices perform the section trace over the STM-1 media segment between them. When
section trace is enabled, the SDH frame carries a trace message in either the J0 byte or the section trace string.
The value you define for Section Trace Message Length determines which field will carry the Section Trace Mes-
sage, as specified below:
• 1-byte section trace message length
—
Use the J0 byte for trace messaging, and ignore the contents of sec-
tion trace string. The value of J0 may be any positive integer in the range of
0 to 255.
• 16-byte section trace message length
—
Use the section trace string for section trace messaging, and ignore
the contents of J0. The value of section trace string may be any alphanumeric text string up to 15 characters
long. The 16-byte field includes CRC-7 in the 16th byte.
• 64-byte section trace message length
—
Use the section trace string for section trace messaging, and ignore
the contents of J0. The value of section trace string may be any alphanumeric text string up to 64 characters
long. The 64-byte section trace string does not include any CRC.
To enable section trace:
1. On the configuration menu, click the SDH hyperlink to display the SDH Overview page.
2. At the top of the SDH Overview page, click the Configuration hyperlink to display the SDH Configuration
page (see figure 67).