Understanding Qos Coefficients - Dell 3-DNS Administrator's Manual

Chapter 8

Understanding QOS coefficients

Coefficient How measured
Packet rate Packets per second
Round trip time Microseconds
Completion rate Percentage of successfully
transferred packets (0-100%)
Topology Score that defines network
proximity by comparing server and
LDNS IP addresses (0-2
Hops Number of intermediate systems
transitions (hops)
Link Capacity Bandwidth usage
VS capacity Number of nodes up
Kilobytes/second Kilobytes per second throughput
Table 8.1 QOS coefficients: Default values, ranges, and limits
8 - 2
Table 8.1 lists each Quality of Service (QOS) coefficient, its scale, a likely
upper limit for each, and whether a higher or lower value is more efficient.
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If you change the default QOS coefficients, keep the following issues in
mind.
◆ Scale
The raw metrics for each coefficient are not on the same scale. For
example, completion rate is measured in percentages, while the packet
rate is measured in packets per second.
Normalization
◆
The 3-DNS Controller normalizes the raw metrics to values in the range
of 0 to10. As the QOS value is calculated, a high measurement for
completion rate is good, because a high percentage of completed
connections are being made, but a high value for packet rate is not
desirable because the packet rate load balancing mode attempts to find a
virtual server that is not overly taxed at the moment.
Example
Default value upper limit
1 700
50 2,000,000
5 100%
0 100
0 64
30 2,000,000
0 20
3 15000
Higher or
lower?
Lower
Lower
Higher
Higher
Lower
Higher
Higher
Lower