User`s guide

Internetwork Monitor
Interpreting the Internetwork View
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Address Placement
Address-based placement assigns each node to a segment based on the
node’s network address:
● For IP addresses, the subnet mask for the host running Internetwork
Monitor is applied to node addresses. All nodes with the same address
after applying the mask are assigned to the same segment.
You can change the subnet mask used by Internetwork Monitor by set-
ting the environment variable NETM_SUBNET_MASK before starting the
application.
● For non-IP addresses, the network or area number component of the
network address is used. All nodes with the same network/area number
are assigned to the same segment.
This placement method is well suited to networks with a high correlation
between network address and physical topology.
You can tailor the network-address to segment mapping by configuring
lines in the file /usr/netm/config/subnet.db. For example, you
might map a Novell network number and an IP subnet to the same
segment.
Traffic Placement
For traffic-based placement, Internetwork Monitor assigns nodes to
segments as follows:
● All devices or nodes that a data source reports are assigned to the seg-
ment on which the data source resides or to the Other segment,
depending on the network and MAC addresses involved. (This process
is discussed further on the following pages.)
● If multiple data sources report the same node, the node’s placement is
based on which data source reports the largest outbound traffic count
for that node over a given query’s duration. To avoid inaccuracies due to
measurement duration differences, packet measurements are normal-
ized over time.