Hungtran,
Those failures rates do not represent the reality, and the subscriber will not “feel” the failure at any point ! It is fully transparent for the subscriber.
For dense urban sites, the failure rate is about 5% to 10%, and for rural sites, it is about 20% / 30%.
It is the same in all Alcatel networks, B5, B6, B7 and B8. And I’ve worked on many Alcatel networks… It’s up to you to trust me or not, but you can always contact RTAC.
Which country are you in ? Hungtran sounds Vietnamese ? I’ve been in Vietnam too, for all three operators (Vietel, Mobifone and Vinafone) 😀