Path Trace; Automatic Circuit Routing - Cisco ONS 15600 Reference Manual

Chapter 7 Circuits and Tunnels

7.9 Path Trace

SONET J1 path trace is a repeated, fixed-length string that includes 64 consecutive J1 bytes. You can
use the string to monitor interruptions or changes to circuit traffic. If the string received at a circuit drop
port does not match the string the port expects to receive, the Trace Identifier Mismatch Path (TIM-P)
alarm is raised. The ONS 15600 can also monitor a 16-byte ITU pattern.
Table 7-6
Table 7-6
Card
OC48/STM16 SR/SH 16 Port 1310
OC48/STM16 LR/LH 16 Port 1550
OC192/STM64 SR/SH 4 Port 1310
OC192/STM64 LR/LH 4 Port 1550
OC192LR/STM64 4 Port ITU C-Band
ASAP OC-N ports
ASAP Ethernet ports
SONET J0 section trace is not supported on ONS 15600 cards.
The ONS 15600 supports both automatic and manual J1 path trace monitoring to detect and report the
contents of the 64-byte STS path trace message (nonterminated) for the designated STS path.
•
•
Note When J1 path trace is enabled on a two-fiber BLSR circuit, CTC will not retrieve the path trace
information from the card view Maintenance > Path Trace subtab.

7.10 Automatic Circuit Routing

If you select automatic routing during circuit creation, CTC routes the circuit by dividing the entire
circuit route into segments based on protection domains. For unprotected segments of circuits
provisioned as fully protected, CTC finds an alternate route to protect the segment, creating a virtual path
protection. Each segment of a circuit path is a separate protection domain. Each protection domain is
protected in a specific protection scheme including card protection (1+1) or SONET topology (path
protection or BLSR).
The following list provides principles and characteristics of automatic circuit routing:
•
•
lists the ONS 15600 cards that support path trace.
ONS 15600 Cards Supporting J1 Path Trace
Automatic—The receiving port assumes that the first J1 string it receives is the baseline J1 string.
Manual—The receiving port uses a string that you manually enter as the baseline J1 string.
Circuit routing tries to use the shortest path within the user-specified or network-specified
constraints.
If you do not choose fully path protected during circuit creation, circuits can still contain protected
segments. Because circuit routing always selects the shortest path, one or more links and/or
segments can have some protection. CTC does not look at link protection while computing a path
for unprotected circuits.
Receive Transmit
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes Yes
Cisco ONS 15600 Reference Manual, R8.0
7.9 Path Trace
7-17