網路 packet drop, jitter, delay 模擬器

NIST Net network emulator
https://www-x.antd.nist.gov/nistnet/



https://wiki.linuxfoundation.org/networking/netem
netem

netem provides Network Emulation functionality for testing protocols by emulating the properties of wide area networks. The current version emulates variable delay, loss, duplication and re-ordering.

ITU-T Recommendations test signals

http://www.itu.int/net/itu-t/sigdb/menu.htm

Below one may find the list of ITU-T Recommendations that contain freely available test signals for download. Each link below opens a webpage with a short description of the relevant content and a link to download the relevant test signals.
In the downloading section, when applicable, one can preview or hear samples of the available signal(s).

voip

網路電話費率比較

yahoo voice
Taiwan $ 0.018
Taiwan, Mobile $ 0.089
Taiwan, Taipei $ 0.020

vbuzzer
TAIWAN $0.020 $0.020
TAIWAN-MOBILE $0.085 $0.08


teltel
臺灣 0.020


skype
所有費率： 價格（不含增值稅）： 價格（含增值稅）：
臺灣 2.3￠ 2.6￠
臺灣 - 免費電話 0￠ 0￠
臺灣 - 台北 2.3￠ 2.6￠
臺灣 - 行動通訊 10.1￠ 11.6￠

全球費率目的地內的通話 全球費率目的地外的通話
連接費 不包括增值稅 包括增值稅 不包括增值稅 包括增值稅
美元 (USD) 0.039 0.045 0.079 0.091