2 intermediate-path performance monitoring – Cisco ONS 15454 SDH User Manual

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Cisco ONS 15454 SDH Reference Manual, R4.6

April 2008

Chapter 15 Performance Monitoring

15.2 Intermediate-Path Performance Monitoring

During the accumulation cycle, if the current value of a performance monitoring parameter reaches or
exceeds its corresponding threshold value, a threshold crossing alert (TCA) is generated by the node and
displayed by CTC. TCAs provide early detection of performance degradation. When a threshold is
crossed, the node continues to count the errors during a given accumulation period. If 0 is entered as the
threshold value, the performance monitoring parameter is disabled.

Change the threshold if the default value does not satisfy your error monitoring needs. For example,
customers with a critical E1 installed for 911 calls must guarantee the best quality of service on the line;
therefore, they lower all thresholds so that the slightest error raises a TCA.

15.2 Intermediate-Path Performance Monitoring

Intermediate-path performance monitoring (IPPM) allows transparent monitoring of a constituent
channel of an incoming transmission signal by a node that does not terminate that channel. Many large
ONS 15454 SDH networks only use line terminating equipment (LTE), not path terminating equipment

Table 15-1

shows ONS 15454 SDH cards that are considered LTE.

Software Release 3.0 (R3.0) and later allows LTE cards to monitor near-end PM data on individual
high-order paths by enabling IPPM. After enabling IPPM provisioning on the line card, service providers
can monitor high-order paths that are configured in pass-through mode on an ONS 15454 SDH operating
in SDH AU4 mode, thus making troubleshooting and maintenance activities more efficient.

IPPM occurs only on high-order paths that have IPPM enabled, and TCAs are raised only for PM
parameters on the IPPM enabled paths. The monitored IPPM parameters are HP-EB, HP-BBE, HP-ES,


The E1 card and STM-1 card can monitor far-end IPPM. For all other cards listed in

Table 15-1

, far-end

IPPM is not supported. However, SDH path PM parameters can be monitored by logging into the far-end
node directly.

The ONS 15454 SDH performs IPPM by examining the overhead in the monitored path and by reading
all of the near-end path PM values in the incoming direction of transmission. The IPPM process allows
the path signal to pass bidirectionally through the node completely unaltered.

Table 15-1 Line Terminating Equipment (LTE)

Electrical LTE


Optical LTE

OC3 IR 4/STM1 SH 1310

OC3 IR/STM1 SH 1310-8

OC12 IR/STM4 SH1310

OC12 LR/STM4 LH1310

OC12 LR/STM4 LH 1550

OC12 IR/STM4 SH 1310-4

OC48 IR/STM16 SH AS 1310

OC48 LR/STM16 LH AS 1550

OC48 ELR/STM16 EH 100 GHz

OC192 SR/STM64 IO 1310

OC192 IR/STM64 SH 1550

OC192 LR/STM64 LH 1550

OC192 LR/STM64 LH ITU 15xx.xx