Prefix type

Prefix types is an artificial construct to ensure consistency in the NIPAP data. Each prefix must have a type, either 'reservation', 'assignment' or 'host'.

'host' are used to document individual hosts in a subnet, while 'assignments' are used to document prefixes with a "specific use", a "subnet". For example, a /30 link network is an 'assignment' while the two individual usable addresses inside the /30 are 'hosts'. RIPE status 'assignment' has nothing to do with the prefix type in NIPAP.

'reservation' differs from 'assignment' in that a reservation is not yet meant for a specific use, ie it is not used in the network. If you want to reserve a larger prefix for use a link networks, you would create a 'reservation', perhaps a /24. Within that network you could then assign /30s or /31s into 'assignments' and in them document the individual hosts. The /24 'reservation' is only reserved for link networks.

As a rule of thumb, you will likely find 'assignments' in the routing table while most 'reservations' will not be in your routing table (except for large aggregates).