The Connected Services Framework (CSF) is an industry-led standard that simplifies switching between business communications providers, ensuring the process is straightforward, consistent, secure, and compliant.
Unlike costly alternatives, CSF can be hosted directly by a communications provider (CP) or through a Managed Access Provider (MAP). It provides a common approach that reduces complexity while remaining flexible enough to meet both industry-wide and individual provider requirements.
Developed by the Technical Architecture Group (TAG)—a collaboration of leading telecom platform providers—CSF v2.0 focuses on business switching, with plans to expand into OTS number porting, wholesale ordering, and outage notifications.
Once adopted by a number of organisations, the intention is to register this standard with an appropriate standards body.
The Connected Services Framework (CSF) is an open, industry-led initiative that standardises communication between telecom providers across the UK.
Built by the Technical Architecture Group (TAG).
Open framework: no license costs, available for any CP or MAP.
Establishes shared standards for secure, direct, and efficient provider-to-provider communication.
Designed to reduce costs and simplify compliance with regulatory obligations.
The CSF framework topology is summarised in the following diagram.
Why CSF Matters
Under Ofcom’s General Conditions (C7 – Switching), business service providers must manage switching when customers move to them. Unlike consumer switching (OTS), which is centrally coordinated, business switching has no single system—leaving over 4,500+ providers to manage processes individually.
This leads to:
Inconsistent and fragmented approaches.
Higher costs and complexity.
Compliance challenges for smaller providers.
CSF solves this by providing a common, standards-based method for transmitting switching messages. This:
Creates a level playing field across the industry.
Ensures consistency and interoperability across providers.
Lowers the cost of compliance.
The benefits of the adoption of this standard for Switching for Business are shown in the following diagram.
Who is involved
The TAG group (active since April 2024) is driving CSF development. Current members include:
Future members could include MAPs offering managed GPLB services and CPs looking to automate intra-CP communications through CSF.
Overview
The CSF standard that was been created incorporates many improvements over the current transport of the OTS messages (via TOTSCo).
Key standard definitions that have been incorporated are:
Alignment as much as possible to the OTS message transport standard to minimise any additional development for any provider already offering OTS services.
Transport of the proposed GPLB message protocol as proposed by the Office of the Telecommunications Adjudicator (OTA).
Process for on/off boarding new providers who wish to adopt the CSF.
Specification of the CP directory
Secure handling of messages using transport and application level security and associated signatures.
Message signings and CP verification using DNS
Service resilience
Change management process
CP transitioning process
Handling of inflight orders
Operational monitoring process
Outage notification and service levels
The latest CSF is published into parts. CSF v2.0 – Part 1 covers the CSF Overview and a desription of the CSF Framework. CSF v2.0 – Part 2 covers the implementation of the CSF. The following buttons take you to the fully searchable markdown document.
Completing sponsorship testing, where an existing member validates the new API connection and messaging.
Sponsorship operates on a cost-recovery basis.
Governance
New members must sign the CSF Memorandum of Understanding (MoU), which defines a governance outline and collaboration.
The MoU is updated periodically, and members may be asked to sign new versions.
Underpinning this CSF MoU is our CSF Governance. See CSF v2 – Part 1 Section 10 and the associated CSF CP Rights Charter (or download pdf) that explains how CSF MAPs support and interact with its Communication Provider customers and how CPs make best use of the services from CSF MAPs.
The following infographic explains how we operate as a group and the governance structure we have put in place without making this overly heavy on administration:
CSF Governance — At a Glance
Connected Services Framework · Part 1, Chapter 10GOVERNANCE AT A GLANCE · v1.1 · 04 · 2026
How CSF Governance works, as the TAG now operates.
A one-page summary of the standards landscape, the TAG’s change process, and the nine governance controls ratified by the steering group on 29 April 2026.
At a glance
The CSF is an open technical standard maintained by the TAG, sitting on top of standards held by OTA2, TOTSCo, and GPLB-SG.
Governance is decentralised by design — the §10.6 controls strengthen it without adding heavy administration.
· The standards landscape · what feeds the CSF
OTA2
Office of the Telecommunications Adjudicator
RCPID Standards
JAM Specification
→ message format & addressing
TOTSCo
Telecoms One Touch Switching Company
OTS Process & Message Specs
Transport Delivery Policy — 9xxx
Hub API Specification
→ OTS compatibility & error codes
GPLB-SG
Switching for Business Steering Group
SfB Process documentation
Matching & Validation Specs
→ business process & content
CSF Standards
TAG
Telecom Technical Architecture Group
CSF Framework & Implementation
Transport Policy — 8xxx
Onboarding & Testing
↺ weekly steering group
· How the CSF changes ·
Five steps, one weekly forum.
1
Proposal. Any TAG member can propose a change.
2
Review. The steering group reviews it at its weekly meeting.
3
Consensus. Changes require consensus among TAG members.
4
Publication. Approved changes are published and versioned.
5
Adoption. MAPs adopt incrementally through API versioning.
↺Decentralised by design. No central administrator; controls are distributed to MAPs and CPs. Self-regulation through DNS, PKI, and directory transparency.
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