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The operation first discovers the hop-by-hop IP route from the source to the destination using a traceroute
utility, and uses ICMP echoes to determine the response times, packet loss and approximate jitter values for
each hop along the path. The jitter values obtained using the ICMP path-jitter operation are approximate
because they do not account for delays at the target nodes.
The ICMP path-jitter operation functions by tracing the IP path from a source device to a specified destination
device, then sending N number of Echo probes to each hop along the traced path, with a time interval of T
milliseconds between each Echo probe. The operation as a whole is repeated at a frequency of once every F
seconds. The attributes are user-configurable, as described in this table.
Table 24: ICMP Path-jitter Operation Parameters
Configured Using
Default
ICMP Path-jitter Operation
Parameter
•
ipsla operation
command
with the
operation-number
argument
•
packet count
command with
the
count
argument
10 echoes
Number of echo probes (N)
•
ipsla operation
command
with the
operation-number
argument
•
packet interval
command
with the
interval
argument
20 ms
Time between Echo probes, in
milliseconds (T)
•
ipsla operation
command
with the
operation-number
argument
•
frequency
command with the
seconds
argument
once every 60 seconds
The frequency of how often the
operation is repeated (F)
Depending on whether you want to configure and schedule a basic ICMP path-jitter operation or configure
and schedule an ICMP jitter operation with additional parameters, perform one of the following procedures:
Configuring and Scheduling a Basic ICMP Path-jitter Operation
You can configure and schedule an ICMP path-jitter operation using the general default characteristics for
the operation.
Cisco ASR 9000 Series Aggregation Services Router System Monitoring Configuration Guide, Release 4.2.x
239
Implementing IP Service Level Agreements
Configuring the ICMP Path-jitter Operation