Final answer:
The missing phrase describes components necessary for a network that are not updated or properly configured. This fits the description of a 'legacy system' or 'legacy network infrastructure' in network administration.
Step-by-step explanation:
The phrase that is missing in the provided statement refers to a collection of components needed for network infrastructure but which haven't been properly configured or updated.
This is typically referred to as a collection of hardware and software that are in place but require proper configuration and updating to become operational or reflect the current specification of a network.
A term that can fit this description is legacy system or legacy network infrastructure, but the specific term to complete the statement has not been provided. It is important in network administration to regularly update and configure devices and software to maintain network security and efficiency.