Not sure I fully understand the issue, but I believe that convergence relates to equipment swaps.  Nokia and Alcatel both had Wireless Network equipment, when the companies merged, they chose between the two sets of equipment, i.e. one was chosen and the other one probably was soon to be "end-of-lifed".  So it is my guess (and that is all it is, a guess) that some customers may have required Nokia to swap their equipment towards the one that was chosen to continue being supported. A costly problem, but one that must be carried out to preserve customers.

I can also understand why Suri states that the workload is heavy and costly.  I am not sure if he has given guidance on when this equipment swaps costs will come to an end.