3Com Switch 8800 Advanced Software V5 Configuration Guide

1098 CHAPTER 86: NQA CONFIGURATION
[Switch-nqa-admin-http] http-operation get
[Switch-nqa-admin-http] http-string /index.htm HTTP/1.0
# Enable the HTTP test.
[Switch-nqa-admin-http] test-enable
# View the test results with the display nqa results command.
[Switch-nqa-admin-http] display nqa results admin http
NQA entry(admin admin, tag http) test result:
Destination ip address: 10.2.2.2
Send operation times: 1 Receive response times: 1
Min/Max/Average Round Trip Time: 15/15/15
Square-Sum of Round Trip Time: 225
Last succeeded test time: 2006-12-28 11:01:07.6
Extend result:
Packet lost in test: 0%
Failures due to Timeout: 0
Failures due to System Busy: 0
Failures due to Disconnect: 0
Failures due to No Connection: 0
Failures due to Sequence Error: 0
Failures due to Internal Error: 0
Failures due to Other Errors: 0
Configuring the Jitter
Test
c
CAUTION: You are not recommended to perform an NQA jitter test on ports from
1 to 1023 (known ports). Otherwise, the NQA test will fail or the corresponding
services of this port will be unavailable.
The jitter test is used to take statistics of delay jitter of UDP packet transmission.
Delay jitter refers to the difference between the interval of receiving two packets
consecutively and the interval of sending these two packets. During the test, the
source port sends data packets to the destination port at regular intervals. The
destination port affixes a time stamp to each packet that it receives and then
sends it back to the source port. After the source port receives the data packet,
the delay jitter can be calculated.
To improve the accuracy of the statistics results, you must send multiple test
packets when you perform a test. The more test packets are sent, the more
accurate the statistics results are. However, it takes a longer time to complete the
test. You can quicken a jitter test by reducing the interval of sending test packets.
However, doing so will cause an impact on the network.
The error in the statistics results of a jitter test is big since there is a delay in both
sending and receiving data packets.
A jitter test requires cooperation between the NQA server and the NQA client. You
must configure the UDP listening function on the NQA server, and a destination
address and a destination port on the NQA client, and ensure that the destination
address and destination port on the NQA client are respectively the listening IP
address and port on the NQA server.