Additional Notes
1) In our hands TCP / UDP packet size can have a dramatic effect. For example, here are typical results using NetStress on an Ethernet network and 802.11 g network:
Effect of TCP Packet Size (1 Data Stream):
| Throughput (KBytes / Sec)
Packet Size (bytes) | Ethernet (100 Mbps) | 802.11 g
------------------------------------------------------------------
8192 | 1400 | 680
65536 | 10000 | 680
131072 | 11000 | 680
262144 | 11000 | 680
1048576 | 11500 | ---
Effect of UDP Packet Size (1 Data Stream):
| Throughput (KBytes / Sec)
Packet Size (bytes) | Ethernet (100 Mbps) | 802.11 g
------------------------------------------------------------------
8192 | 180 | 200
16384 | 325 | 350
32768 | 600 | 600
49152 | 900 | 900
65507 | 1200 | 1100
2) When mixing TCP and UDP data streams, then TCP wins. That is, when adding TCP data streams then UDP rates drop dramatically compared to what they were in the absence of TCP data streams. It appears that Windows gives priority to TCP data streams.
3) The maximum 'Packets Per Second' depends on the network rating.
The maximum ethernet frame payload is 1500 bytes (not considering Jumbo frames), which yields a frame that consists of 1526 bytes plus a 12-byte inter-frame gap, for a total Maximum Frame size of 1538 bytes.
Here's an example for a 100-Mb/s ethernet link:
100,000,000 bits/sec divided by (1538 bytes * 8 bits/byte) equals 8127 packets.
Network Rating |
Maximum Packets Per Second |
11-Megabits / sec |
896 |
54-Megabits /sec |
4392 |
100-Megabits / sec |
8127 |
150-Megabits / sec |
12,192 |
300-Megabits / sec |
24,384 |
1-Gigabits / sec |
81,272 |
In the dialog box used to set Packets Per Second the maximum value for Packets Per Second is adjusted according to the network rating and may be rounded up or down such that it is divisible by 8.
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