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The spread of 5G and optical technologies in the access network and in the backbone, together with Edge Cloud Computing, Virtualization and Automation of networks allows a wide range of very high quality and low latency service offers capable of adapting quicky to traffic growth and demand change.

This continuous evolution over the years, as well as the complexity of switching off services from old networks, has led to technology stratification with some very obsolete platforms still in use. In this scenario it is exceedingly essential to find ways to modernize all network layers making them more efficient, lean and future proof.


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Articolo 06 - Legacy Tech...

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Introduction and Context

Decommissioning of legacy networks and platforms (local exchanges, copper, 2G/3G, PSTN, ATM, SDH, PDH, ...) is a challenge to guarantee operational simplification and to implement important savings (e.g. related to energy consumption, facilities management, rental fees), reduce the risk of faults and enable revenues (e.g. selling equipment, copper cables, real estate).
The process is mostly driven by ultrabroadband deployment, allowing new customer services and collecting possible government incentives. Decommissioning hence, contributes to the achievement of Government Digitalization targets (1Gbit/s to all Italian families by 2026) and of the Green Revolution (reduction of greenhouse gases) included in the National Recovery and Resilience Plan.
In addition, there are serious security risks related to legacy technologies still in use: long transformation periods of both network equipment and IT systems (often imposed by external constraints) increase the risk of attacks, as there are often no more updates available to secure legacy systems. On the other hand, customer reluctance, major investments in the short term and long notice periods are the main barriers as well as the obligation to continue providing legacy services at the wholesale level.


Decommissioning in Italy: legislative framework and regulatory constraints
In Italy AGCOM regulates decommissioning activities with resolutions on different issues. Regarding the possibility of dismissing central offices, there are constraints on broadband services coverage and penetration, while, concerning low speed transmission circuits on legacy technologies, there has been the withdrawal of obligations on new activations (1), (2). In any case, a long way must still be gone to obtain, for example, End of Life and End of Maintenance status of old network platforms such as PDH and SDH. However, it should be noted that the switch-off of local copper exchanges is object of a specific article of the New European Communications Code (3) that gives the National Regulatory Authority the possibility of withdrawing access obligations relating to the copper network, once an adequate migration process has been established.
This with the objective of creating a legislative framework favourable to decommission legacy networks.

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Figure 1: From Arthur D Little- Copper switch off: Opportunity to drive infrastructure convergence? October 2021

click here to enlarge the image

Decommissioning outside Italy: what is the trend?
The following two pictures summarize what is going on with respect to copper and 2G/3G. In general, to promote the decommissioning of legacy networks, European regulatory best practices encourage migration to the best technology available by increasing wholesale prices of legacy services and declaring the End of Sale. Furthermore, a new rule of the Code of Electronic Communications allows operators to upgrade fixed access technology without customer's consent.

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Figure 2: Boston Consulting Group 2021 Benchmark for TIM

click here to enlarge the image

Current Situation and Plans

In the next paragraphs a summary of obsolescent TIM (and subsidiaries, where specified) networks/platforms will be given, specifying decommissioning plans and strategies when available. As a general consideration, dismission or substitution of old equipment ensures savings on energy and operating costs and reduces the risks of faults, strengthens IT security and enables new services provisioning. These benefits won’t be repeated in the following, while other specific advantages or peculiar issues will be described in detail.


Central Offices
The decommissioning of Central Offices, besides great savings on energy and rental fees, brings revenues from building disposal: about 6.700 Central Offices out of a total of more than 10.500 could be released when copper-based services will be migrated to new fiberbased ones.
In relation to that, accelerating NGAN/FWA plans is critical in achieving the goal and is compliant with the constraints imposed by the already mentioned regulatory rules.


Fixed & Mobile Access
On fixed access, ATM DSLAMs need to be migrated to IP ones since they are obsolete and out of support (a swap plan started in 2015 and is still ongoing), and moreover migration from ADSL (based on copper) to FTTx services (based on fiber) should be boosted, as already said, also on the regulatory level. On mobile radio access, the 3G switchoff project aims at closing 3G service and reusing related frequencies for more advanced technologies: it will start in April 2022 with a closing target by June 2022.
In addition to the costs and benefits common to all decommissioning projects, 3G Switch Off requires marketing expenses, for dimensional extensions (e.g. VoLTE) and interconnection systems but enables the release of backhauling and core network resources.
About 2G, there’s no switch-off plan at the moment, rather its capacity will be pushed to support the voice traffic swap from 3G. In addition to what described above, around 60 Operational Support Systems of access domain competence are in an obsolescence state, but their replacement is not always feasible because of the obligation to keep running some outdated services (e.g., for regulatory and/or marketing constraints).


Transmission networks have been evolving since the ‘80-90s starting with PDH, SDH and then WDM: most of those pieces of equipment are still running, despite the End of Sale/Support of the technology or even supplier withdrawal from the market. Spare parts shortage, shorter life cycle after repair, skilled support hardly available are just examples of the issues to manage and about the same ones can be applied for their Element Managers (many different systems with multiple instances each). Although a decommissioning project of SDH/PDH and old DWDM networks has been analysed several times in the last two decades, two main reasons have prevented its realization: extremely high costs and regulatory constraints on commercial services.
Indeed, the only way to empty and switch-off PDH/SDH networks in a sustainable way would probably be to migrate the customers towards Ethernet based connection services. Even, if necessary, with regulatory imposition. With regard to obsolescent packet transport technologies, there are ATM nodes, ATM to IP gateways, Switches and old routers mostly in End of Support, without forgetting tens of thousands of old Ethernet CPEs. Switches will be removed as the R-Evolution project (Ref. 4) is implemented, while for the other equipment a plan must be still defined, considering that some business and wholesale services can’t be properly replaced.


Edge and Core Network
This network segment contains platforms enabling both fixed and mobile, voice and data services, characterized by different stages of technology (physical, virtualized, cloud native) and aging. For this reason, a general treatment is not suitable and some hints about the main legacy platforms are reported in the following.


Legacy Fixed Voice Transit Network (BBN)
BBN network was the first Telecom Italia technology for long distance fixed calls using IP and replaced the full TDM SGT network. Since 2011 a new full IP Class IV network (GTW/M) has been deployed but currently on BBN there are still fixed OAOs interconnected in TDM: the nodes can be turned-off only if all OAO traffic migrates on IP interconnection and actions must be taken at regulatory level to achieve this goal.


Legacy VoIP Platforms
The first Voip solution for consumer and small business customers in Telecom Italia network (Pk3) was implemented in the 2000s. Starting from 2014, the IMS technology was added to manage all types of customers and services and the migration towards it is about to be completed. For private telephone networks, a new cloud native and IMS solution was deployed in 2020 to replace the old one (Pk0), and since 2021 migration has started but a swap tool that applies to all on-premises PBXs must still be developed.


Interactive Platforms & “Voice” Services
An evolution path of the bare metal nodes of the legacy platforms towards a modern, agile, flexible, scalable, secure architecture is ongoing and enabling advanced interactive services through the use of innovative voice resources (e.g. IVR Services, Digital Contact Center, Vocal Portal, Voting, Fundraising, Utility, etc.).


Wireline Service Layer
Many transformation solutions have been (or are being) defined for legacy telephony services (e.g., Public Telephony Service, Carrier Selection, Number Portability and others) to migrate to a cloud environment and operative plans are still under e valuation.


Signaling Network Evolution
The current platform (Eagle5ISS) handles all wireline network signaling layers and a migration towards a new virtual/cloud application named vSTP has been defined. One couple of virtual nodes is already handling traffic but another one is needed to complete the migration.


NAM and FEV platforms
The FEV (Voice/Signaling Front-End) and NAM (Multifunction Access Nodes) platforms deliver mobile traffic and signaling to the transit devices towards the IP/MPLS BackBone (OPC). Both platforms are critical assets for the Italian Government Resilience Decree and their traffic will be migrated to the new NAM+ nodes by the end of 2025.


RA/PE Business connectivity platforms
At the end of 2021, there were hundreds of obsolete ATM and IP devices in these platforms and the migration for those devices is following different approaches. A decrease of customers is expec ted for ATM because of autonomous termination of contracts while on obsolete IP devices there may be a decrease in customers also due to swap towards a most recent technology. Anyway, customer migration is very complex as there are multiple services on each node and above all the deployment of new resources will be needed.


Service Platforms
At the Service Layer level, platforms decommissioning is considered as part of the Transformation path for systems and platforms evolution, where it is essential to identify and assess (measure, control and reduce) vulnerabilities and obsolescence. Transformation projects are complex with multifaced activities including optimization of systems/platforms processes with simplif ication (keeping platforms) and rationalization (some platforms are decommissioned). A target of such transformation is becoming “lean”, that is minimizing complexity, delayering, and pushing innovation. In the medium/long term, efficiency will become the main objective with growth achieved by means of flexible resources. Opportunities associated to obsolescence management and decommissioning are numerous, for example: facilitating the connection to the ecosystem, through the microservice/API approach; taking advantage of optimization for migration to the cloud; replacing equipment with more eco-responsible solutions; increasing the number of Service Platforms developed internally. Expanding internal development capabilities for new native cloud platforms and re-platforming of existing platforms is allowing TIM to pursue significant benefits such as renewing internal competencies reducing time and costs, governing strategic assets, eliminating vendors’ lock-in increasing flexibility for services go live. Through this Transformation projects path for Service Platforms, TIM will be able to play a key role in a wider ecosystem of application service offering, an opportunity to create and deliver (jointly with partners) new revenue-generating enterprise services.


IT decommissioning plan is part of the ongoing transformation initiatives guided by the following rationalization and simplification principles:

  • simplifying the company architectural landscape and overcoming technology obsolescence;
  • enabling integration and synergies among Software Development factories;
  • implementing future-proof technologies in all the application domains;
  • rationalizing costs for Application Development and Application Maintenance. Consistently with these guidelines, in general the initiatives involve two different activities:
  • implementing a new application or service to replace the functionality of an old one;
  • removing the old application while ensuring effective access to data that must be kept for regulatory or legal purposes.

In the coming three year plan, the commitment to reduce applications will continue: while the main objective is always the implementation of new services/capabilities, the decommissioning stream is critical to achieve simplification and exploit the opportunities of new technologies.


The main decommissioning activities in 2021-22 include old DWDM and SDH, the older PEs and core routers, while on the IT side they concern the older ticket monitoring, inventory and management systems. Furthermore, on the basis of specific agreements made with the involved consortia, two submarine cables will be released within next year after the two already dismissed in 2020-21.


Noovle strategy to become the only Public Cloud Provider authorized to deliver Google Cloud services in Italy is based on three main guidelines: building new DCs, rationalizing existing ones, increasing automation and efficiency. To achieve these objectives, it is mandatory to renew the connectivity among existing DCs: the target solution is to connect each DC to dedicated PEs into TIM national central offices with new high-capacity connections, thus replacing the old VDCN network.


TIM Brasil
On mobile network TIM Brasil and VIVO, another Brazilian mobile operator, decided to reduce 2G footprint through an agreement, in which one of the operators turns off its 2G network where both are present, inside a perimeter of about 1100 cities, enabling the possible frequencies refarming for 4G. In addition to this, TIM Brasil is planning to complete switch off legacy 3G Network within 2025. In this meanwhile, 3G coverage can be partially deactivated in cities and regions where 4G devices penetration is close to 100%, and both voice and data services can be held by LTE network, also allowing refarming to 4G. Other initiatives are ongoing to reduce the consistency of SDH, PTN, old DWDM and old IP routers.


The evolution of Telecom Italia network over the years has led to a technology stratification with some very obsolete platforms that cannot be dismissed yet for various reasons (customer reluctance to migration, costs, regulation, …). If the shutdown of obsolete technologies involves considerable investments, on the other hand it’s crucial to guarantee a higher efficiency in energy consumption as well as to improve network resilience to the risk of failures and avoid increasing difficulties in maintenance. A way to reduce decommissioning expenses would be to address a migration towards services based on new technologies rather than replicating them on new equipment. This process anyway, as we can see in some other countries, should be accelerated by a proper regulation in line with the New Electronic Communications Code (4) and with the governmental objectives expressed in the PNRR.

Contributing Companies

Contributing companies to this article are: TIM, TIM Brasil, Sparkle, Noovle, Fibercop.


(1) Delibera n. 348/19/CONS - AGCOM

(2) Delibera n. 333/20/CONS - AGCOM

(3) art. 81, European Electronic Communications Code (EU Directive No. 2018/1972), transposed in Italy in November 2021 with Legislative Decree 207/2021.

(4) La R-Evolution del trasporto. Notiziario Tecnico TIM-3-2020.


ADSL: Asymmetric Digital Subscriber Line

AGCOM: Autorità per le Garanzie nelle COMunicazioni

API: Application Programming Interface

ATM:  Asynchronous Transfer Mode

BBN: BroadBand Node for fixed voice calls transit

DCME: Digital Circuit Multiplication Equipment, a voice compression device

DSLAM: Digital Subscriber Line Access Multiplexer

DWDM: Dense Wavelength Division Multiplexing

FEV: Voice/Signaling Front-End

FTTx: Fiber To The x (FTTC, FTTB, FTTH, FTTO etc.)

FWA: Fixed Wireless Access

IMS: IP Multimedia Subsystem

ISDN: Integrated Services Digital Network

IVR: Interactive Voice Response

LTE: Long Term Evolution

MPLS: Multi Protocol Label Switching

NAM: Multifunctional Access Nodes

NGAN: New Generation Access Network

OAO: Other Authorised Operator

OPC: Optical Packet Core

PBX: Private Branch Exchange, equipment for private telephone networks

PDH: Plesiochronous Digital Hierarchy

PE: Provider Edge router, a boundary device between a service provider’s area network and a customer’s one

PNRR: Piano Nazionale di Ripresa e Resilienza

PSTN: Public Switched Telephone Network

SDH: Synchronous Digital Hierarchy

SGT: Stadio di Gruppo di Transito

STP: Signal Transfer Point

TDM: Time Division Multiplexing

VDCN: Virtual Data Center Network

VOIP: Voice over IP

VoLTE: Voice over LTE

WDM: Wavelength Division Multiplexing