LSO Sonata

Frictionless inter-provider commerce.


LSO Sonata APIs address the business-to-business layer of inter-provider buying and selling at the commercial level. Much of the work to date has focused on this critical Interface Reference Point in the LSO Reference Architecture.

LSO Sonata APIs combine product-agnostic products and services schema to support all phases of business-to-business transactions using automation APIs for the retail-wholesale ecosystem.

LSO Sonata’s latest release, “Billie,” includes support for automated business functionalities, including address validation, site query, product offering qualification, quote, product order, product inventory, and trouble ticketing for Carrier Ethernet (CE) connectivity services. Additional functions, such as billing and settlement, and support for additional payloads (e.g., Internet Access) will be available in future releases. The full release is now available to MEF members, with a subset available publicly.

See MEF’s Technical Standards & Educational Materials for LSO Sonata

In The Spotlight

Introducing new services, programs, and resources to accelerate LSO Sonata implementation.

MEF has introduced a portfolio of commercial and technical resources designed to support service providers throughout all stages of their LSO Sonata adoption journey.

Find out how MEF LSO business APIs helps organizations monetize digital services—faster:

Hear from John Nolan at AT&T about the importance of standardizing on LSO Sonata APIs:

LSO Sonata Interface Reference Point

LSO Sonata is the Interface Reference Point between the business applications’ layers of federated service providers who connect with one another to provide access or transit services for a service provider’s end subscriber.

Business Applications’ Layer Interface Between Providers

Diagram showing Sonata API

MEF 3.0 LSO Sonata Frequently Asked Questions

The communications industry is undergoing a multi-year transformation to dynamic, secure, and certified services across a global federation of automated networks, as envisioned in the MEF 3.0 framework. Service providers worldwide are not only becoming more automated internally to deliver solutions with user- and application-directed control over service capabilities. Many also are collaborating to build an emerging business ecosystem of automated networks that will support rapid delivery of digital services across multiple providers and reduce friction in connecting enterprise users to cloud applications.

To realize this vision, MEF has advanced initiatives related to a full family of standardized MEF 3.0 services – including Carrier Ethernet, SD-WAN, IP, Optical Transport, and SASE – as well as standardized MEF 3.0 LSO (Lifecycle Service Orchestration) APIs that are foundational to orchestrating these and other services across federated networks.

MEF is standardizing LSO Sonata APIs as part of a comprehensive effort to standardize multiple sets of LSO APIs enabling service automation across providers and network technology domains. LSO Sonata APIs relate to the interface reference point within the LSO Reference Architecture that supports automated business-to-business interactions between service providers. Similar APIs at the LSO Cantata interface reference point support automation of business functions between service providers and enterprises.

With the latest “Billie” LSO SDK Release in June 2021, MEF now provides a robust set of LSO Sonata APIs for address validation, site query, product offering qualification, quote, product order, product inventory, and trouble ticket. These APIs initially support automation of Carrier Ethernet Access E-Line and CE subscriber services, as shown in the table below.

The “Celine” LSO SDK Release scheduled for November 2021 will introduce new support for Internet Access and will mature all LSO Sonata APIs and Developer Guides to pass another MEF member Call for Comments (CfC), with some advancing to Letter Ballot – the final stage of MEF member and Board approval before standards are published.

The “Dolly” LSO SDK Release scheduled for May 2022 is expected to include new LSO Sonata APIs for billing & settlement and product catalog.

MEF plans for future SDK releases following Dolly to support additional MEF-defined and MEF endorsed services.

MEF’s LSO API Framework provides a set of SDKs released every six months that contain APIs, tools, documentation, and underlying standards for service automation across providers, between providers and enterprises, and within providers.

  • LSO SDK repositories are publicly available on GitHub and use GitHub teams as a communication channel.
  • Extended SDK versions are available exclusively for MEF members. They contain work-in-progress elements and pre-release standards.

Members can contact the LSO Developer Community Manager,, and visit LSO Sonata SDK on the MEF Wiki for more information.

Consider the case of a large enterprise customer with data centers and branch offices located around the world. This customer is looking for a service provider to provide connectivity to all their locations. No single service provider has facilities to reach all customer locations. Typically, a service provider can reach some of the locations (on-net locations) but must work with a set of partners to reach the other locations (off-net locations).

The interaction between service providers and partners to deliver services to a single customer may involve proprietary APIs and portals but is predominantly manual across the industry – involving emails, spreadsheets, negotiations, etc. – resulting in long time periods and costs to set up required connectivity. Accelerating these processes through automation provides cost savings and greater business value to the end customer. It also removes much of the potential error inherent in manual processes.

With hundreds of service providers and partners in the world, it would be prohibitively expensive and time consuming to implement custom automation for each service provider–partner pair. MEF’s LSO Sonata APIs provide an industry standard so that a service provider (buyer) may implement these APIs and automatically work with all their LSO Sonata-enabled partners. Similarly, a partner (seller) may implement these APIs, enabling automation with their LSO Sonata-enabled partner service providers.

The top three LSO Sonata benefits identified by service providers are: (1) accelerate service delivery, (2) accelerate time to revenue, and (3) improve customer experience and loyalty. More than two-thirds of 28 service providers surveyed by MEF described these benefits as having “high value.”

Other significant benefits include efficiencies that lead to additional revenue from new orders with API-enabled partners, scaling with predictability, reduced operational expenses, and the potential for new revenue from multi-provider on-demand services.

At a strategic level, implementation of LSO Sonata APIs enables service providers to participate in an emerging global networking federation with frictionless commerce. Federation participation will ultimately create an opportunity to provide higher margin, highly differentiated dynamic services across multiple providers that leave behind low-margin fixed-bandwidth services.

A large and growing number of service providers worldwide are embracing LSO Sonata APIs to automate business functions between providers. The pace of the transition to the APIs has picked up significantly with the latest “Billie” LSO SDK Release in June 2021.

Recent research from MEF indicates that at least 29 companies are either in production with LSO Sonata or intend to be by the end of 2023, including 23 companies by the end of June 2022. Twenty-eight companies have implemented LSO Sonata or intend to as a seller, and 14 have implemented LSO Sonata or intend to as a buyer. These numbers are likely to increase as market awareness grows and buyers increasingly call upon their seller partners to align to LSO Sonata APIs.

MEF is closely tracking LSO Sonata adoption through one-to-one engagement with MEF member and non-member companies.

Thirteen companies in production with LSO Sonata APIs as of September 2021 include:

  • AT&T
  • Axtel Networks
  • Bloomberg
  • China Unicom Global Limited
  • Colt Technology Services
  • HGC Global Communications
  • Lumen
  • Orange
  • PCCW Global
  • Sparkle
  • Telefónica Global Solutions
  • Telia
  • Zayo

The 16+ companies committed to implementing LSO Sonata APIs include:

  • CMC Networks
  • Proximus
  • TIME dotCom
  • Verizon Business Group
  • 11 other service providers

MEF has introduced a broad range of commercial and technical resources to make it much easier for service providers of all sizes to adopt LSO Sonata APIs. These are designed to support service providers throughout all stages of their adoption journey. Chief among the new programs are MEF’s LSO API Onboarding & Interop Test (OIT) Service and MEF 3.0 LSO Sonata Certification.

See the LSO Sonata resource page for links to a number of these resources.

MEF members can find more information on these resources and the standards-related work of MEF committees in the LSO Sonata Adoption Tracker (available exclusively for members).

MEF’s LSO API Onboarding & Interop Test (OIT) Service offers an efficient, predictable, and scalable solution that service providers can use to test their LSO Sonata implementation and to perform interop testing with partners. It consists of software-based LSO Sonata Buyer & Seller Emulators hosted on a dedicated public cloud server for a subscriber.

Offered through Amartus, a MEF-Authorized Test and Certification Partner, the OIT Service is scheduled for general availability in October 2021.

See the MEF Solution Brief – LSO API Onboarding & Interop Test Service for a quick overview.

See the FAQ – MEF LSO API Onboarding & Interop Test Service for details.

MEF 3.0 LSO Sonata certification is a subset of the new MEF 3.0 LSO API certification program formally launched in September 2021. It builds upon MEF’s years of experience providing service, technology, and professional certifications for Carrier Ethernet and SD-WAN services.

MEF 3.0 LSO Sonata certification enables buyers and sellers of wholesale connectivity services to validate that their suite of APIs used for inter-provider business transactions conform to MEF standards. Tested and certified LSO Sonata APIs are a combination of four elements listed below.

  1. Buyer or seller
  2. Business function
  3. LSO Sonata release
  4. Product payload

Offered through Iometrix, a MEF-Authorized Test and Certification Partner, MEF 3.0 LSO Sonata certification is scheduled for general availability in October 2021.

See the MEF Solution Brief – MEF 3.0 LSO Sonata Certification for a quick overview.

See the FAQ – MEF 3.0 LSO Sonata Certification for details.

The following are key contacts:

What Can I Achieve with LSO Sonata APIs?

Starting with MEF 3.0 Carrier Ethernet services, and later for all MEF 3.0 services, LSO Sonata APIs drive frictionless inter-provider business processes and commercial interactions, resulting in the potential for near real-time service delivery worldwide.

MEF LSO Sonata API advantages:

  • Accelerate service delivery.
  • Accelerate time to revenue.
  • Improve the customer experience and loyalty.

Learn More about LSO Sonata:

Educational Materials:

MEF LSO Sonata APIs – Frequently Asked Questions — 2021 Nov

Product Portfolio: LSO Sonata

MEF LSO Sonata APIs – Frequently Asked Questions

Learn More

The Case for Standardized and Automated Inter-Provider Business Interface — 2020 Feb

Also See: Business and Operational Aspects of Implementing LSO Sonata

Product Portfolio: LSO Sonata, Carrier Ethernet

This paper is aimed at those decision makers within ICT-SPs (Information and Communications Technologies Service Providers including traditional telcos, MSOs, MNOs, cloud operators and other entities involved in wholesale supply of data services) and their wholesale data services partners that are discussing adoption of standardized and automated inter-provider business interfaces.

Learn More

Business and Operational Aspects of Implementing LSO Sonata — 2020 Feb

Also See: The Case for Standardized and Automated Inter-Provider Business Interface

Product Portfolio: LSO Sonata, Carrier Ethernet

This White Paper is aimed at service providers that have made a decision to create a standardized zero-touch/automated inter-provider commercial and business interface based on MEF’s extensive LSO Sonata APIs and underlying standards.

Learn More

MEF 3.0 Workshop – Inter-Provider Automation – LSO Sonata Roadmap & Use Cases — 2019 Nov

Product Portfolio: LSO Sonata

LSO Sonata is the corner-stone effort of inter-provider service automation, enabling service provider partners to use automation to manage their service-oriented business functions, from serviceability to order. Initial service automation is focused on MEF 3.0 Carrier Ethernet services, delivering increased business velocity for the service provider and its enterprise customers.

Learn More

MEF 3.0 Workshop – MEF 3.0 LSO Sonata Certification — 2019 Nov

Product Portfolio: LSO Sonata

MEF LSO Sonata Certification will enable the verification and resulting business velocity to inter-provider service automation by establishing and validating adherence to the LSO Sonata API standards.

Learn More

Technical Standards & SDKs:

LSO Framework Release ‘Billie’ — 2021 Jun

Product Portfolio: LSO Legato, LSO Sonata, LSO Presto

The theme of this release is Ordering and Inventory: it delivers full coverage of Business Requirements, API and API Developer Guides for Ordering and Inventory API functions. NOTE: Some parts of the release are for MEF Members only.

Learn More

MEF 80 Quote Management – Requirements and Use Cases — 2021 Jul

Product Portfolio: LSO Sonata

This specification identifies the common Quote Use Cases and attributes needed to support intercarrier Quote management.

Learn More

I want to investigate further. See all LSO Sonata resources:

What the industry is saying about LSO Sonata

Be In the Market

Engage in Positioning LSO Sonata for the Marketplace

Major service providers have implemented LSO Sonata to automate ordering MEF 3.0 Carrier Ethernet Access E-Line services. The LSO Sonata SDK is continually evolving and expanding to include all aspects of business-to-business interaction between providers for service automation. As a MEF member, you can help lead the market in adopting service automation. Find the current project work in the MEF 3.0 LSO Sonata Hub on the MEF Members’ Wiki.

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