Dear all,
I wrote the FIFO delay patch some years ago. The measured average and jitter are different from the nistnet settings. The FIFO delay patch relies on a basic functionality which creates a kind of traffic jam where packets cannot be reordered. Since packets are not reordered, the average and the variance cannot be computed because the mathematical law is not linear. Basic probabilistic rules do not apply. It relies on the max () operator. The FIFO delay patch produces a density curve which looks like a Gaussian curve but it does not fit in. There is a low probability to get a huge delay on a packet because all packets are linked together (there is no reordering). In that case, this will increase the delay but have not much effect on the jitter. The image of the traffic jam is good. If a car slows down, the interval (i.e. the jitter), gets locally smaller between the cars but finally remains the same. This is what happens with nistnet and this is quite realistic. Yours sincerely, Mr Laurent MARIE ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of ??? Sent: jeudi 28 août 2008 07:13 To: nistnet@antd.nist.gov Cc: [EMAIL PROTECTED] Subject: [nistnet] Nistnet with FIFO patch Hi everybody, I am using Nistnet with FIFO patch, it rectify the reorder of packets. But, when i measure the jitter with Iperf tool, the measure result is not correlation to the jitter parameter setted in the Nistnet command line. for example, in the Nistnet command line, the jitter is 50ms, the measure result of Iperf is about 20ms, but when the jitter is 500ms, the measure result of Iperf is still about 20ms or even less than 20ms. but when i turn off the FIFO path, the measure result of Iperf is close to the jitter value of command line for Nistnet. thanks for help! Best Regards! Shirley 熊礼霞/Shirley 华为技术有限公司 北京研究所 Huawei Technologies Co., Ltd. Beijing Department tel: 010-82836120 cell: 13466690531 ------------------------------------------------------------------------------------------------------------------------------------- 本邮件及其附件含有华为公司的保密信息，仅限于发送给上面地址中列出的个人或群组。禁 止任何其他人以任何形式使用（包括但不限于全部或部分地泄露、复制、或散发）本邮件中 的信息。如果您错收了本邮件，请您立即电话或邮件通知发件人并删除本邮件！ This e-mail and its attachments contain confidential information from HUAWEI, which is intended only for the person or entity whose address is listed above. Any use of the information contained herein in any way (including, but not limited to, total or partial disclosure, reproduction, or dissemination) by persons other than the intended recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender by phone or email immediately and delete it!
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