GZMCC FTP service testing performance improvement (2007)

Hantele designed FTP service performance improvement service, breaching the traditional approach, by combing the testing and signaling data collecting, tracking and analyzed the volume of signaling information closely related to GPRS services (such as Um, GPRS Abis, Gb, or even Gn, Gi at the higher layer). This innovative approach helped the operators to analysis and allocate network problems. This result shows major factors that affects the FTP service performance. Hantele moved forward with an an optimization proposal for improvement and clean up of the signaling process for FTP services. Hantele further improved KPI for FTP services to  include the speeds of uploading and downloading.

Service Case: GZMCC NOC reported there often found latent data transfer interruption during  the DT&CQT.

【Problem Description】
There often found data transfer interruption even under the situation of good radio environment and plenty of radio resources.

【Analysis】
Observed of the Gb and Gn signaling information collected from testing, we found TCP window did not set any limitation to the downlink data. However the downlink packets is too small. The terminal sets the TCP receiving window to the maximum and ask the sender for more data transfer. During this period, the terminal repeated a “TCP ACK” message  more than 40 times with the same packet sequence number (1137388760), which means packet lost and data re-transferring.  The “TCP ACK”observed from FTP server shown is depicted as follows:

【Solutions】

Hantele recommended optimization adjustment for the configuration parameters in the FTP server to remedy the performance limitation .