A core network device of a telecommunications network can receive a first request from a consumer network function (NF) and forward the first request to a first provider NF. The device can subsequently detect a violation by the first provider NF of a response criterion. The device can receive a second request and forward the second request to a second, different provider NF in response to the violation. In some examples, the device can later detect that the first provider NF has satisfied the response criterion with respect to a third request. The device can modify load data to increase the proportion of subsequent requests for which the first provider NF is selected. The device can select provider NFs based on the load data. In some examples, a system can include a network registry device that selects NFs based on violation indications received from the core network device.