Specifying An Aggregation Policy - 3Com Traffix Transcend Traffix Manager User Manual

130 A C: A
PPENDIX GGREGATING
Specifying an
Aggregation Policy
D
EVICES
To aggregate devices on a particular network, it is necessary for the
aggregator to be configured for that network. This is done by specifying
an aggregation policy.
Once an aggregation policy has been configured, it only affects data
collected from that point on.
An aggregation policy consists of three parts: a local domain
specification, a default action and a maximum device limit.
Local Domain Specification
As well as reducing the amount of memory and disk resources required,
aggregation is also an intuitive way of specifying which devices are of
interest and should therefore be monitored closely. You can specify a list
of the DNS domains which will be referred to as the local domain(s).
These are the domains which you want to retain at device-specific level
for detailed monitoring. Any device whose resolved DNS domain matches
one of these specified DNS domains, or a sub-domain of one of the
specified DNS domains, is considered to be local and will be kept in detail.
Only IP addresses can have a DNS domain, and therefore only IP
addresses are considered for aggregation. Non-IP network devices are
always be considered to be local, and so will be kept in detail.
You can assign DNS domains to subnets using the SubnetsDB file.
Subnets can be assigned any DNS domain, but 3Com suggests that you
use local domains. If you provide a local DNS domain name for a subnet,
a device in this subnet will be placed in this domain, if DNS lookup fails
for the device. This ensures that such devices appear in the correct group
when you use the DNS grouping.
When Traffix Manager discovers a new IP device on your network, it
performs a DNS lookup for the DNS name of that device. If this lookup
fails, or if your site has no DNS, Traffix Manager will check the SubnetsDB
file to see if the device is in a given subnet. If so, it will assign the DNS
name of the subnet to the device. If the device is not found in SubnetsDB,
then a final check is done to see if it is in the same subnet as the Traffix
Manager Server. If it is, the device is assigned to the subnet
home-subnet and the DNS domain is set to that of the server (if it has
one). You can override this behavior by making sure that there is an entry
in the SubnetsDB file for the subnet of the Traffix Manager Server. See
"Using the SubnetsDB File" on page 133 for more information.