This document provides guidance on procuring standard business applications to replace N3 overlays. These guidelines are intended to be relevant regardless of the network used to access the applications, and may be used when procuring a service accessed over HSCN or the internet.

In particular, N3 contracted voice and video overlay services must be replaced in advance of your HSCN migration, as they cannot migrate to any replacement third party HSCN suppliers service. 

The N3 contracts on these voice and video services will then need ceasing prior to the migration of the N3 network to HSCN.

N3 overlays are types of business applications services that have standard offerings traditionally supplied by network providers, but are now available from a range of suppliers through current government procurement routes. These routes support the government "Cloud First" policy to procure more off-the-shelf products from a more competitive range of suppliers.

There are generic considerations for any application services that they must meet, and some specific functional requirements. This document details the generic guidance for health and social care consumers to consider when procuring applications, and then guidance on specific functionality and service considerations for each type of service to replace the specific N3 overlays.

Replacement services are considered for the following N3 overlays:

1. N3 voice - hosted voice service (HVS) and local gateway service (LGS)
2. N3 video conferencing services
3. N3 remote access solution VPNs (tokens)
4. N3 other overlays (such as routers, cards, ports, managed firewalls, wi-fi and local area networks)
5. Site to site VPNs (tunnels)

This is a technical document and should be used by:

• Information Management & Technology (IM&T) management and staff working in NHS and social care organisations intending to procure business applications services
• IM&T staff looking to replace/upgrade existing N3 contracted overlay services
• suppliers of services to the NHS or wider public sector

This document will cover various aspects of procuring a business application service and the considerations for a purchasing organisation. It includes the following sections:

Business applications - generic guidance

This section details the generic guidance that should be followed when procuring any application service.

HSCN considerations

This section details considerations to include if the application is to be delivered over the HSCN. It is not necessary to run these services over HSCN; if a service can be delivered to meet the requirements over the internet or from cloud-based services then this is permitted. 

N3 overlays replacement guidance

This section gives specific guidance for the N3 overlays:

1. Procurement routes
2. Application specific requirement considerations