Network Transformation: PSTN/ATM decommissioning


Network modernisation and structural transformation projects

The Scenario

Technological evolution, decreasing revenues from traditional services, competition pressure and the increasingly strong market presence of the Over The Top are pushing all Telecommunications Operators towards a continuous process of modernisation and structural transformation of their networks (“network transformation”).

This evolution requires a rethinking of network infrastructures with the aim of drastically reducing operating costs and making the introduction of innovative services faster and more flexible

Transforming a network into operation, especially if it consists of several layers and many interconnected technological generations, is a very complex activity.

The implementation of such transformations, especially with approaches starting from the lowest network levels, implies a great impact on operations and territorial organisation.

The Challenge

The Network Decommissioning project of the customer TIM arose from the need to reduce costs resulting from the space used and energy consumption with the aim of rationalising and reorganising the centres (SdL, SGU).

This was achieved along two lines:

  • PSTN: compaction of legacy RTG users and eventual migration of PSTN services to VoIP platforms with elimination of obsolete platforms (S12, UT100, AXE)
  • ATM: migration and compaction of TGU DSLAM ATM to IP platform

The Solution

In tackling Network Decommissioning projects, Sirti was able to integrate knowledge of old-generation (“legacy”) networks and equipment, expertise on all technological layers and delivery capabilities.

The execution of this project required in-depth knowledge and excellent control of the customer’s operational dynamics, therefore guaranteeing:

  • design service capable of interacting correctly with all the different TIM Databases involved (DatiPlan, Sigra, etc.)
  • definition of innovative plant solutions to improve the speed of migration execution, thus minimising inefficiencies on end users
  • massive territorial interventions in the power plant (with peaks of up to 3,000 permutations/day)
  • maintenance supervision of impacted lines (post-compaction and post-migration assurance) with challenging SLAs.

In the period 2015-2020, about 700 centres were subject to PSTN compacting/migration, with about 2.2 million legacy ports switched off.


  • Network decommissioning
  • Network consolidation
  • IoT monitoring