Tuesday, March 6, 2012
AIRTEL 3G SERVERS DISABLE CALLS?
All signs point the problem to the newly deployed Airtel 3G network.
The reason calls could not be made apparently was because of problems within the Mobile Switching Centre - this is the modern day equivalent of the old telephone switches (PTSN) - which apparently could not route calls properly.
Typically, the (VLR) Visitor Location Register, a table of active mobile users that have been detected by the network that day, and the Home Location Register (HLR), the database of all Airtel SIM card users should have the same information since the VLR is linked to the switching centre which regularly updates the HLR.
But for some reason, while signalling seems to have been working okay, the forwarding plane which in some networks is a table that has the addresses that the router needs to look up and forward the signal/message to was not.
By around 2PM it seems the problem had largely been dealt with.
That being said, it can only lead to one conclusion: That the problem was occasioned by the deployment of a 3G Core Network when the company announced its 3G rollout.
Because it cannot arbitrarily migrate to 3G when so many Airtel users are on 2G/GSM handsets, Airtel must have decided to support 2G in its 3G core network.
Many Mobile Switching Centres (MSS) allow for implementation of GSM.
Ericsson which is the company involved in this particular case, runs what it calls a MSC_S, from where it runs the control and bearer functionalities of the switching centre.
It is here where it must have implemented support for Airtel's 2G/GSM.
Most likely, this was a configuration issue - growing pains so to speak.
Of concern however is that it is here that also billing functions take place and with such downtimes and general confusion, subscribers who didn't complete calls could have been accidentally billed and others not billed.