RFC2544 Performance Testing
--2010.11.29
Throughput
吞吐量, 各自包长, 在不丢包的前提下, 得出DUT在不同的包长的最大转发速率, 为Throughput; Throughput 和 包长有关, 完整的报告中包括同一DUT的每个包长的Throughput值;
Definition:
The maximum rate at which none of the offered frames are dropped by the device.
Measurement units:
N-octet input frames per second input bits per second
Issues:
single path vs. aggregate
load
unidirectional vs bidirectional
checksum processing required on some protocols
Procedure: Send a specific number of frames at a specific rate
through the DUT and then count the frames that are transmitted by the
DUT. If the count of offered frames is equal to the count of received
frames, the fewer frames are received than were transmitted, the rate
of the offered stream is reduced and the test is rerun.
Discussion:
The throughput figure allows vendors to report a
Latency
延时, 各自包长, 在使用throughput得出的速率下, 对DUT进行发包延时的测试.
Definition:
For store and forward devices:
The time interval starting when the last bit of the input frame reaches the input port and ending when the first bit of the output frame is seen on the output port.
For bit forwarding(cut through) devices:
The time interval starting when the end of the first bit of the input frame reaches the input port and ending when the start of the first bit of the output frame is seen on the output port.
Measurement units:
Time with fine enough units to distinguish between 2 events.
Procedure: First determine the throughput for DUT at each of the
listed frame sizes. Send a stream of frames at a particular frame
size through the DUT at the determined throughput rate to a specific
destination. The stream SHOULD be at least 120 seconds in duration.
An identifying tag SHOULD be included in one frame after 60 seconds
with the type of tag being implementation dependent. The time at
which this frame is fully transmitted is recorded (timestamp A). The
receiver logic in the test equipment MUST recognize the tag
information in the frame stream and record the time at which the
tagged frame was received (timestamp B).
Back-to-Back
规定速率规定报文长度下，DUT能够Burst报文个数（不丢包）。
Definition:
Fixed length frames presented at a rate such that there
is the minimum legal separation for a given medium
between frames over a short to medium period of time,
starting from an idle state.
Measurement units:
Number of N-octet frames in burst.
Procedure: Send a burst of frames with minimum inter-frame gaps to
the DUT and count the number of frames forwarded by the DUT. If the
count of transmitted frames is equal to the number of frames
forwarded the length of the burst is increased and the test is rerun.
If the number of forwarded frames is less than the number
transmitted, the length of the burst is reduced and the test is
rerun.
Frame Loss
Definition:
Percentage of frames that should have been forwarded
by a network device under steady state (constant)
load that were not forwarded due to lack of
resources.
Measurement units:
Percentage of N-octet offered frames that are dropped.
To be reported as a graph of offered load vs frame loss.
Procedure: Send a specific number of frames at a specific rate
through the DUT to be tested and count the frames that are
transmitted by the DUT. The frame loss rate at each point is
calculated using the following equation:
( ( input_count - output_count ) * 100 ) / input_count
The first trial SHOULD be run for the frame rate that corresponds to
100% of the maximum rate for the frame size on the input media.
Repeat the procedure for the rate that corresponds to 90% of the
maximum rate used and then for 80% of this rate. This sequence
SHOULD be continued (at reducing 10% intervals) until there are two
successive trials in which no frames are lost. The maximum
granularity of the trials MUST be 10% of the maximum rate, a finer
granularity is encouraged.
#Reference
1, rfc1242_Benchmarking Terminology for Network Interconnection Devices.pdf
2, rfc2544_Benchmarking Methodology for Network Interconnect Devices.pdf