East Sussex County Council is looking to deploy a wide area network (WAN) that will cover a range of public sector organisations across East Sussex, West Sussex and Brighton and Hove.
It is estimated that the contract could last up to 10 years and be worth up to £100m, according to an online tender.
As well as providing a managed WAN to public-sector premises, the selected provider may also be required to deploy services to affiliate organisations, such as charities and private-sector partners.
"The provider will maintain and implement operational procedures and standards to fulfil and satisfy the demands of the public sector and in response to public-sector policy demands," reads the tender.
"[It will also] evaluate and pilot new networking technology for the life of the contract and maintain services in line with evolving business needs and technical opportunities, exploiting relevant opportunities to maximise value from the network infrastructure."
East Sussex is looking for a partner that will provide all technical, commercial, training and support services.
It also suggests that the winner of the contract will work with Broadband Delivery UK, the body tasked with allocating money to ISPs for fibre rollout, to extend the availability of broadband services in the area.
Interested parties have until the 28 November to express interest in the tender.