METRODATA NetTESTER FAMILY USER MANUAL
76-02-107 Rev.A
Page 47 of 133
10.3.1.1 Basic Test
The basic test regime, as the name suggests, allows for simple tests with specified
rate, duration and packet size(s). Two such tests, with independent parameters, may
be run in sequence, allowing for a short 'go/no-go' phase, followed by a longer 'soak'
phase. Packet loss, delay and delay variation measurements are made and
compared with the SLA to produce pass/fail results.
10.3.1.1.1
Packet Sizes
The packet size is defined excluding tags, such that where a 64-byte packet size is
requested, the actual packet may be
Untagged
64 Bytes
Single Tag
68 Bytes
Double Tag
72 Bytes
Note, that a double tagged 1518-byte frame will generate a 1526-byte frame which
exceeds the standard 1522 IEEE limit, so where double tagging is used, mini jumbo
or jumbo frame support is required from the network.
10.3.1.2 RFC2544
RFC2544 [7] defines methods of measuring the performance (in terms of throughput,
delay and burst handling) of a network connection. Though it wasn't originally aimed
at service activation testing, it has become one of the most well-used methodologies
in this area.
The RFC2544 test procedure is made up of three self-contained tests, to measure
the three performance criteria listed above.
10.3.1.2.1
Throughput Test
In essence, the approach of the RFC2544 throughput test is: "Try passing traffic at
different rates and look for the highest rate that has no lost packets. Then repeat the
process for a number of different packet sizes."
10.3.1.2.1.1 Short Test Phase
This process is, by its nature, time-consuming. In order to speed it as much as
possible, the unit uses a binary search algorithm and performs short (10 second)
tests at each rate.
Since arriving at an exact result would take an impractical number of iterations, the
search terminates once it has reached a figure that is within a +/-1% window.
The unit allows an upper limit to be set for the test which, if set appropriately, can
help to further cut the testing time. 8 iterations (taking around 2 minutes in total) is
typical.
10.3.1.2.1.2 Long Test Phase
