Scrum is a project management method, it is not specifically aimed at software development ; so it can be used for network enhancement project.
You said you're struggling with "sprint that never finishes", that is not Scrum. Sprint are timeboxed, they finish on time, period.
Now, if the team overcommitted for the sprint, or if some tasks were underestimated, and there are backlog items that are not "done done", they are removed from the outcome of the sprint, and may be continued in the next sprint.
There are several things you can do to prevent overcommitement :
- backlog items shall be small ; small items are easier to estimate that large items. Actually, they should have INVEST characteristics. EDIT: the backlog items should be sized so that the Team can complete between 5 and 10 in one Sprint, on average.
- after the first sprint, you now how
much the team can put in a sprint
(provided comparable ressources)
- do not allocate people 100% on the sprint, start with 80% as a rule of thumb
- define what "done" means
- re-estimate your backlog items based on what your learnt
If the network enhancement project never finishes, I assume it is because new needs are identified. Add them in your backlog, prioritize them, estimate them, they will eventually be scheduled in a sprint.