Most of cloud telephony service providers use a facility, “Call Forwarding” telecom operators in India where a “virtual IVR” number is provided to a cloud Telephony service user. Now this number is normally a 10 digit mobile number which is mapped to a “PRI number” which is essentially a land-line number. This virtual number is mapped to the PRI number by using call forwarding facility where every call coming to that 10 digit mobile number ( either GSM or CDMA) is forwarded to the PRI number unconditionally.
This is really a good arrangement in terms of redundancy simply because if a PRI goes down for some reason, the number can be forwarded to another PRI number and nobody will realise any downtime for the IVR service!
Another advantage is, normally this kind of forwarding allows up-to 30 channels per number. So, a single 10 digit number becomes a phone with multiple lines which multiple incoming calls could be answered simultaneously.
With this kind of arrangements, all Cloud Telephony Service providers claim to have service uptime of 100%, automatic fail-over or redundancy.
While, these claims seem true, but there are certain conditions where this smart arrangement fail miserably though I will not hold cloud telephony companies responsible for that, but some out-dated policies in India.
India has many telephone service providers. Now this “Call Forwarding” facility has many terms and conditions, one such condition is:-, Call forwarding is possible only to numbers of the same operator. Which means, if the Virtual Number belongs to X Operator, it can be only forwarded to PRI lines of X operator! This policy is not very clear why it is so, and I had tried to find information from various telephone operators, But I could not get any satisfactory replies from them.
Incidentally, this same policy even applies to toll free numbers too, not only mobile/CDMA numbers.
This small one line policy put a big question mark on claim of 100% uptime by any cloud Telephony service providers. What happens when all PRI lines of the X operator goes down? And normally, PRI goes down that way, network outage takes place for all services of one operator.
It is high time, such policy is changed and then virtual number for cloud telephony service will be truly redundant and with 100% uptime.