Top 10 Factors for a Successful Migration Strategy

Over the past few years, Next Generation Network migration has been one of the most popular topics in the Communication and Media industry. Those carriers initially reluctant to consider and start the migration process are beginning to feel a true sense of urgency as the competitive market continues to transform and grow. The introduction of more sophisticated services such as unified communications and office mobility are beginning to flood the market, requiring carriers offering legacy services to quickly explore options and develop strategies on "how" to migrate instead of continuing to ask themselves, "Do we migrate?"

Considering the infancy of migration engineering and process complexity that requires extensive resources, carriers are realizing that a specialized migration team is necessary. An attempt to undergo a legacy-to-NGN migration on their own will ultimately lead to migration failure. Partnering with a team of engineers, project managers and experts with specific migration expertise is critical to ensure overall migration success while minimizing service impacts, expense overages and delays. Qualified migration teams are skilled in the following areas:

  • Developing a detailed, end-to-end migration plan addressing all three states of a transformation: current, interim, and end-state
  • Evaluating all options across the five dimensions of a migration project: network architecture, subscriber data, product and service feature sets, and operational support systems (OSS/BSS)
  • Managing the over-arching tasks and resources involved for the entire project lifecycle
  • Facilitating, communicating and managing the transformation across functional areas and internal departments of the organization
  • Defining and mapping the product and service feature sets of existing legacy switch to the Next Generation Network
  • Providing cross-functional training and support to technical and operational staff
  • Developing and implementing a risk mitigation, rollback and contingency plan specific to migration projects from technical, operational, and financial perspectives

Partnering for success with a qualified and experienced migration team will fill the gaps in resources that universally exists among all service providers attempting a migration. No matter how robust and skilled your "home team" may be, a migration project will require resources strictly dedicated to a migration project in program management, product and service development, engineering support, and technical and operational expertise. With these gaps filled, service providers can continue to focus on the day-to-day operation of their business and focus on revenue-generating activities, still necessary and running parallel as the migration project is implemented.

Building a Successful Migration Strategy: Top 10 Factors

  1. Develop a detailed end-to-end migration plan that covers all dimensions
  2. Identify and optimize your network migration approach
  3. Architect and validate the network for high availability and security
  4. Review and improve call routing
  5. Maximize the accuracy and efficiency of your OSS/BSS integration across systems
  6. Create and document step-by-step Methods of Procedures (MOPs) for each migration event improving the process and increasing the size of subscriber groups as you gain more experience
  7. Develop an effective test strategy and perform a pilot migration for each migration event and/or central office
  8. Train operational and technical staff and coordinate vendor support
  9. Identify potential risks and develop a rollback/contingency plan
  10. Partner for success with a qualified migration and program management team

#1: Develop a Detailed End-To-End Migration Plan That Covers All Dimensions

The migration planning phase is the cornerstone of a successful migration project. A well-documented plan and migration strategy combines the network and operational analysis, detailed network architecture transition and step-by-step migration approach and cutover process.

In order to establish a "baseline" and clear starting point for your migration strategy, a detailed survey and evaluation of the current network and operational support system should be performed. The survey should assess the current equipment, signaling, transport, products, service and feature sets, traffic, network statistics, operational systems, applications and any other resources to include staff and their skillsets. Some of the key components in a current network and operational survey would likely include:

  • Colocation Sites
  • Trunking
  • SS7 Architecture
  • Data Aggregation
  • Physical Real Estate
  • Number of Subscriber Lines
  • Transport
  • TDM Aggregation Devices
  • Core Routing
  • DACs, MUXs, DSLAMs
  • LATAs Served
  • Switching
  • Echo Cancellation
  • Billing Platform
  • Service Packages
  • Network Diagrams
  • Gateways/DLCs
  • Voicemail
  • Inventory / OSS System
  • Product Feature Sets

In review of this information, migration requirements should be determined based on the carrier's priorities for service and subscriber migration, network consolidation and new service availability. Together, the migration requirements and survey results is used to develop a network and operational design for the interim (transition-state) and end-state. Together the current survey, interim and end-state design of the network and operational architecture will make up the foundation for the overall migration plan. This migration plan will take that foundation and describe, in detail, all processes and resources necessary to implement each stage of the network and operational support environment across all five dimensions of a Next Generation Network migration:

  • Network Architecture – Signaling, Transport, Access
  • Data – Subscribers and Lines.
  • Operational Support Systems (OSS/BSS)
  • Product & Service Features
  • Traffic – Call Routing and Processing

Key considerations and additional sections of a migration plan should discuss the migration approach (Point-Code, Point Code Sharing, Flash Cut, Local Number Portability, etc.), resource planning and scheduling, staff plans, internal and customer communication, training, migration timeline, pilot migrations, vendor coordination, Methods of Procedures MOPs for cutover, testing strategy, risk and dependencies, rollback and contingency and decommissioning.

Creating and documenting a detailed end-to-end migration plan is the #1 factor because it's the one single project component that determines project's degree of success. Following a well-developed migration plan throughout the project lifecycle ensures imminent success.

#2: Identify and Optimize Your Network Migration Approach

There are several migration approaches to consider when moving subscribers over to the new softswitch environment. The most recommended approach allows the migration of subscribers in phases, usually determined based on geography, central office and transport/access types. Using a phased approach offers many benefits to include the least risk of service impacts, minimal down-time and offers a more manageable rollback and technical support plan in case something goes wrong. Switch and call routing configuration approaches include Point-Code Sharing, Local Number Portability, Flash Cut and New Point Code. Point-Code Sharing is a method where the new softswitch sits in front of the legacy switch and shares the point code of the legacy switch. This approach reduces the need for ordering a new point code and provisioning new SS7 or other trunking. This method allows subscribers to be cut over incrementally and reduces migration lead time. However, this approach requires support and maintenance of two switch platforms until all subscribers are migrated. Flash Cut is usually only recommended with a small subscriber base, so an incremental cut using Point Code Proxy or Point Code Sharing would likely be the appropriate migration approach for a carrier with more than 1,000 subscribers. Subscriber group size can increase as more experience is gained throughout the migration project.

A carrier's network engineering team along with a support team from switch vendors and a qualified migration partner can assist in determining the best approach based on your subscriber base and network topology.

#3: Architect and Validate the Network for High Availability and Security.

One of the key drivers behind moving a legacy network to a Next Generation Network is the ability to cost-effectively improve service availability. Selecting the proper carrier class of softswitch, peripheral equipment and deployment model will ensure a high availability of features without compromising the integrity of services in an event of hardware, network or process failure.

Careful consideration to call capacity and routing must be given to offer protection against potential service-affecting events for items such as call control and management, bearer plane handling, enhanced application access and service availability. A well-designed configuration with redundancy and peak call-volume in mind, detailed contingency and fail-over plan and detailed process mapping of an effective communication and support strategy will protect against breaches of Service Level Agreements (SLAs) and keep operations running smoothly in the event of a failure.

#4: Review and Improve Call Routing

The migration project offers an opportunity to review and redesign for more efficient call routing and translation strategies. For example, systems that use bulk loading updates for least cost routing may be redesigned to implement a dynamic least cost routing strategy which increases capacity and capabilities to support millions of routes on a call-by-call basis. Adding better translations for security such as blacklisting would protect against brute-force attacks and other security breaching. Implementing these types of new call routing strategies will dramatically increase operational efficiency and service quality.

#5: Maximize the Accuracy and Efficiency of Your OSS/BSS Integration Across Systems

Transforming to a Next Generation Network softswitch platform should offer streamlining capabilities to your operational systems. Integration across these systems should be performed only after data cleansing has taken place on the current subscriber and provisioning data. Once the accuracy of data is confirmed by data validation procedures and testing, this data must be mapped to the new softswitch databases and throughout the transitional and end-state OSS/BSS environment to be imposed after full migration. Proper mapping and data synchronization between the current legacy, interim, end-state network and OSS architecture is crucial. Multi-state testing must be performed to ensure that billing and provisioning operations will process subscriber data, billing and service features correctly throughout the migration process.

Accurate integration should begin with an assessment of the OSS/BSS platforms including monitoring, billing, provisioning, performance, alarming, reporting and performance. Call Detail Records and feature-sensitive billing requires special attention. Before the first migration event, several tests incorporating every possible CDR field combination should be ran to ensure the correct billing functions are applied and the billing team must confirm any field and formatting changes. Additional field offerings provided by the Session Border Controller platform should also be incorporated. Sample Call Detail Records can be provided for analysis, data mapping and testing.

#6: Create and Document Step-By-Step Methods of Procedures (MOPs) for Each Migration Event Improving the Process and Increasing the Size of Subscriber Groups as You Gain More Experience

Detailed Methods of Procedures should be created with cut-over plans specific to each migration event. Method of Procedure documents should be provided to all staff involved on cut-over day to include tech support staff in your Network Operations Center, engineering and operational support team. MOPs should provide information such as:

  • Task Details
  • Cut Sheets
  • Subscriber Group Information
  • Resources and Responsibilities
  • Task Timeline
  • Specific Rules and Procedures
  • Issue Resolution and Escalation Plan

Pilot migrations must be performed on specific migration event characteristics such as subscriber types, transport and access equipment and geographical footprint following the designated cut-over plan and MOP in order to ensure a successful migration event. MOPs and cut-over procedures can be edited and optimized and the size of subscriber groups can increase as your migration team gains experience throughout the overall migration project.

#7: Develop an Effective Test Strategy and Perform a Pilot Migration for Each Migration Event and/or Central Office

Establishing an effective test strategy and benchmark is crucial to ensuring the network and subscribers have transitioned to the new environment correctly. This process includes establishing pretesting, pilot migration and post cut-over testing. Various testing points should be determined and a detailed checklist should be included in a migration event test strategy. Network transition testing should cover components such as system, service, feature functionality, trunk, access, signaling and security.

An effective test strategy will ensure current subscribers receive at least the same level of service quality they are accustomed to, with better service quality as an ultimate goal. In addition, a comprehensive testing strategy should also include the ongoing maintenance of the network and visibility into network performance and functionality of current services and any additional service features to be offered and added with the Next Generation Network switching platform. With the addition of new capabilities, your testing strategy and procedures should be edited to accommodate these new features and capabilities.

#8: Train Operational and Technical Staff and Coordinate Vendor Support

Proper training of operational and technical support staff is crucial to the success of your migration project because it offers the carrier a maximum return on investment to the Next Generation Network architecture. Although most switch and application vendors supply training resources and manuals, these resources rarely provide information on interoperability and integration. How these work together is the most important aspect of your deployment. A qualified migration partner employing voice network and OSS/BSS subject matter experts experienced with your current legacy environment, new NGN softswitch and gateways, signaling technology and operational support system can offer a more effective training program with customized references and documentation. Training topics would likely include all, but not limited to:

  • Navigating the GUI of call management, provisioning, billing, network monitoring, etc.
  • Provisioning templates and feature data synchronization
  • Call routing and translations
  • Troubleshooting hardware, applications and service features
  • Call traces and call feature interactions
  • Call Detail Records (CDRs)
  • Bill processing and usage-sensitive provisioning
  • Provisioning methods and procedures across systems
  • Network alarms and reporting features
  • Security

Comprehensive, customized training resources will ensure your provisioning, engineering and operational teams are comfortable with the new environment and offer all staff the opportunity to perform at maximum productivity.

#9: Identify Potential Risks and Develop a Rollback/Contingency Plan

A successful migration strategy must identify possible risks and a contingency and rollback plan must be developed and provided to all involved in the migration project. Some of the most common risks associated with migration projects include schedule delays, interoperability issues with network equipment, technical issues with call routing, call handling and capacity and operational issues with network provisioning and maintenance. Many of these should be identified and addressed during the interim state and build (pre-migration) and testing phases. Further identification and evaluation of the potential risks associated with the dependencies of each migration phase – Assess, Build, and Migrate – should minimize the opportunity for the presence of these risks and offer a prompt resolution to any issues throughout the migration project.

The most common risk in carrier-grade migration projects are schedule delays and account for most cost overruns. Insufficient attention to coordination among vendors and internal departments or incorrectly estimating the time requirements for specific tasks are the usual contributors to delays. Implementing a program management approach to oversee across all dimensions and organizational functions is the most effective preventive to this risk.

#10: Partner for Success with a Qualified Migration and Program Management Team.

Partnering with a qualified migration project team fills the gaps in resources – staff, expertise, time availability, etc. These gaps exist universally – no matter the competencies and staffing capabilities of the carrier. The fact that most network engineering, operational, project management, product development and technical support staff lack the necessary migration experience is no surprise since the need is nonexistent during normal operational circumstances. Carriers manage resources such as staffing, skillset and time availability based on daily operations, support and current technology requirements in accordance with the switching platform of the carrier's currently deployed network. Engineering, management and support for migration and chosen Next Generation Network and associated operational architecture rarely exists in parallel to the current legacy network and operational environment. Partnering is crucial during the transformation. Project failure is highly likely, especially at carrier level, if a service provider does not partner with a specialized migration team.


In order to build a successful migration strategy, carriers need the ability to continue to focus on business growth and support activities while performing the migration and network transformation. A qualified migration partner is crucial in enabling a carrier's ability to continue functioning and performing the activities necessary in providing customers a satisfactory level of service quality, offering the new service features supported by the Next Generation Network, building and nurturing business relationships with large enterprise customers which will still be required and ultimately continue to run parallel to a migration project. Carriers need to partner with a migration team that can offer staff augmentation, supplemental resource availability, overarching management across various functions and internal departments and operational and network expertise during the migration. Doing so will offer the carrier and carrier's staff migration and post-migration success – both equally important in building a successful migration strategy.

For more information on how Excelacom can help you build a successful migration strategy, please email us at