Discovery Range Sets in ServiceNow Discovery offer a flexible way to manage and identify networks. They simplify the administration of network discovery by allowing administrators to define groups of IP ranges.
This organization helps in effectively managing and targeting different network segments without needing to define each IP range in individual Discovery Schedules. Range Sets do not necessarily show the number of IPs in a subnet, nor are they the only way to define multiple IP ranges in a schedule.

Hardware Models are templates that define the attributes and default values for a specific type of hardware configuration item (CI). Hardware Models can have a one-to-many relationship with the following entities:
* Assets: An asset is a tangible or intangible resource that is tracked and managed by the organization, such as a laptop, a license, or a contract. A Hardware Model can be associated with multiple assets that share the same characteristics and specifications.
* Configuration Items: A CI is any component that needs to be managed in order to deliver an IT service, such as a server, an application, or a user. A Hardware Model can be associated with multiple CIs that share the same characteristics and specifications.
* Model Categories: A model category is a classification of Hardware Models based on their function, such as network, storage, or server. A Hardware Model can belong to one or more model categories that define its scope and usage.
References:
* Hardware Model
* Asset
* Configuration Item (CI)
* [Model Category]

Discovery uses the ping method to determine if a host IP is active or alive. Ping is a network utility that sends an ICMP echo request packet to a target IP address and waits for an ICMP echo reply packet. If the target IP address responds, it means that the host is active or alive12.
References:
* 1: ServiceNow Discovery Documentation, Discovery Process section
* 2: ServiceNow Discovery Overview, page 8