Parameters for provisioning a path trace
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To make sure the traffic is not delivered to the wrong destination, a path trace can be
set. A label (TTI), for example a word, is inserted in the path overhead. To check if the
path is correctly provisioned the received path trace is compared with the expected
value. A path trace can be set on the VC-12,VC-3, and VC-4 signals. On TU-12 and
TU-3 termination point, only the expected value can be set.
Example of a path trace
J0/J1/J2 trail trace identifier
The Trail Trace Identifier (TTI) is inserted in the path overhead. For STM-N signals
the J0 byte in the RSOH is used, for VC-4/VC-3 signals byte J1 is used and for VC-12
signals byte J2 is used. For the TTI a 16 byte frame is composed which includes one
CRC-7 byte for error detection. Therefore the TTI can be 15 bytes long (15 characters
or 30 hexadecimal digits). The J0/J1/J2 Trail Trace Identifier area is divided into three
subsections:
• Transmitted TTI: The TTI inserted in the path overhead is sent to the other side of
the path.
• Expected TTI: The TTI expected from the other side of the path.
• Accepted TTI: The TTI actually received.
TI mode
The TI mode can have the following values:
• Specific String: The TI is a string with maximum length of 15 bytes. This string is
identified in the Access Point Identifier (API). In Alphanumeric or ASCII format
any alphanumeric character can be used, in HEX format only 00 .. 7F can be used.
• Non Specific Byte: The Trace Identifier matches if it is any constant byte value
within the range 00 .. FF. If the byte value is not constant, Trace Identifier
Mismatch is assumed. No check between Accepted API and Expected API is
performed.
Traffic maintenance
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365-312-807R7.2
Issue 4, May 2007
Alcatel-Lucent - Proprietary
See notice on first page
9-17
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