Network policies provide rules and guidelines on what network users can and cannot do. Most networks in large organisations will have network policies in place.
An AUP states how the network may be used – what is and is not acceptable. If you are going to let people use your network, then you should have an agreement in place which states the rules and guidelines for users.
Networks often have to store a lot of data. A good archiving strategy takes old, non-essential data and puts it somewhere safe. An archiving policy will help decide when to move data, where it should be kept, and how to get it back if needed.
There are more details about how to make a network reliable in Reliability and backing up.