How to request network resources just-in-time using smart contracts

5G promises unprecedented levels of network connectivity to handle diverse applications, including life-critical applications such as remote surgery. However, to enable the adoption of such applications, it is important that customers trust the service quality provided. This can only be achieved through transparent Service Level Agreements (SLAs). Current resource provisioning systems are too general to handle such variety in applications. Moreover, service agreements are often opaque to customers, which can be an obstacle for 5G adoption for mission-critical services.In this work, we advocate short-term and specialised rather than long-term general service contracts and propose an end-to-end Permissioned Distributed Ledger (PDL) focused architecture; which allows operators to advertise their service contracts on a public portal backed by a PDL. These service contracts with clear Service Level Agreement (SLA) offers are deployed as smart contracts to enable transparent, automatic and immutable SLAs. To justify our choice of using a permissioned ledger instead of permissionless, we evaluated and compared contract execution times on both permissioned (i.e. Quorum and Hyperledger Fabric) and permissionless (i.e. Ropsten testnet) ledgers