Special Considerations For Configuring Probes; Special Considerations For Icmp Echo Probes - HP 7102dl - ProCurve Secure Router Configuration Manual

Network Monitoring
Configuring Network Monitoring
9-18

Special Considerations for Configuring Probes

The following sections list special considerations for ICMP echo probes, TCP
connect probes, and HTTP request probes.

Special Considerations for ICMP Echo Probes

ICMP echo probes are used to test the current status of paths to particular
networks or endpoints. Therefore, you should typically set the destination to
the gateway device of the network in question. (You would not want a track
to remove a route to an entire network simply because one endpoint in that
network lost connectivity.)
The timeout value that you select depends largely on the purpose of the probe:
If the probe is testing connectivity only, set the timeout higher so that a
congested but functional route is not removed.
If the probe is monitoring congestion, set the timeout lower so that the
track is triggered when an average packet's transit time falls below the
acceptable standard. In this case, you might want to set the tolerance
according to rate of failure.
For ICMP echo probes, you can also configure these additional packet
settings:
size
data pattern
source address
Setting the Size. The default data length for an ICMP echo packet is
64 bytes. (The header size is fixed at 28 bytes, resulting in a total packet size
of 92 bytes.)
You can customize the size of the data portion of an ICMP echo packet.
Remember, though, that the default size is the minimum size and so adds the
least overhead.
To set the length of the packet's data field, from the network monitor probe
configuration mode context, enter:
Syntax: size <data length>
The valid range for the length is from 64 to 1448 bytes.