Recently we made an investigation that how higher jitter and pacaket loss affect in fax tranmission resulting in high number of dropeed faxes. One of our customer has persistant complain about high number of dropped faxes on one server among his three ICTBroadcast ( asterisk ) servers that instigated us us to plan a through investigation in this regard.
The customers has three ICTBroadcast ( asteirsk ) servers in production with each server capable to broadcast 500 concurrent outbound fax calls over T.38 protocol and one server among these three has persistant complain regarding high number of dropped faxes,
We have developed and installed a script on all three servers, to monitoring QoS of underlying network. we are glad that after running that script for two days we have enough data to reach a conculsion that high number of dropped fax issue is related to undrlying network performance rather than software performance also we are pleased to share it with you for your feedback.
In following we have prepared a table showing network statistic for all three servers and named these servers as Server A, Server B and Server A . Server A is the server which has been reported as high number of dropeed Faxes.
After analysis , We found that server-C has much higher jitter ratio and at least double packet loss ratio as compared to other servers.
To confirm these results , we have compared network statistics of “individual calls”. Here, in 2nd image, we have arranged / grouped answered calls in two categories i.e calls with successful fax delivery, and calls with broken fax. Again we can see that calls with broken fax are having at least 4 times higher jitter and packet loss ratio.
