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Stage 5 - call-off, implementation and migration

Part of the HSCN customer journey for aggregated procurements.

Further details on this stage will be published in due course. The paragraphs below summarise this stage at a high level. 

Stage 5 consists of the three following phases: 

Call-off - contract signature

The process by which consumers will place orders for new HSCN services from an HSCN compliant supplier. For consumers who are procuring through the aggregated procurement route, this would be a call-off contract. A call-off contract is a framework agreement with a supplier, where a customer can select and order (call-off) from a range of services available. Broadly the activity will include:

  1. Due diligence - upon receipt of a new order, the consumer network service supplier (CN-SP) will engage with the consumer to perform due diligence activities. These will often involve requests for additional information, conducting site surveys and confirming the services and connections currently in place.
  2. Order placement - once the due diligence is complete, the CNSP will be able to confirm a new order and advise a firm order confirmation date. The delivery date will depend upon the services ordered and availability within your local area.

A CN-SP is any HSCN supplier engaged in providing HSCN services to customers.


The HSCN Migration Checklist provides details of the actions you'll need to take at each stage of your migration to HSCN from the Transition Network.

Involves the delivery, testing and sign-off of new HSCN services. Implementing new access connectivity services will include:

  1. Circuit delivery - providing a new service to the customer premises
  2. Commissioning tests - a set of tests to ensure the new access connectivity services are functioning as expected. This will often involve a customer sign-off from an appropriate individual.


Migration involves cutting-over from existing legacy connectivity to the new HSCN service shortly after the replacement service is commissioned. Migration activities will vary dependent on the circumstances but for a new replacement service will typically involve:

  • a go/no-go decision - a decision point with the appropriate stakeholders to confirm the new service is live and all parties are ready to proceed with migration
  • pre-migration tests - a set of checks to confirm access to production applications is available before the start of migration
  • network changes - a set of activities to cutover to the new service
  • post-migration tests - a set of checks to confirm the network change has been completed successfully and access to production applications is available
  • go/no-go point - in the event that the post-migration tests have identified an issue, there should be a planned decision point to agree whether to rollback or attempt to investigate and resolve the issue - in the event of rollback, the migration will need to be rescheduled
  • regression testing - depending on the customer organization, additional IT infrastructure and business application tests may be performed to provide assurance that these are unaffected by the network change
  • migration complete - once all tests are satisfactorily complete, the customer should sign-off the migration complete with the parties involved

Both the implementation and migration activities should adhere to your normal change management governance and procedures. 

In an aggregated procurement, although NHS Digital will centrally manage legal support during the mobilisation and execution of the procurement, if you wish to seek local legal advice prior to signing your call-off contract you will need to pay for this yourself.

Last edited: 21 May 2019 2:56 pm