inet6num: 2404:c8::/32 netname: NTT-IDNIC-ID-20060413 descr: NTT Communications Groups descr: PT. NTT Indonesia descr: Internet Service Provider descr: Jakarta country: ID admin-c: HN60-AP tech-c: SS271-AP remarks: spam and abuse report : firstname.lastname@example.org mnt-by: MNT-APJII-ID mnt-lower: MAINT-ID-NTTNET status: ALLOCATED PORTABLE mnt-irt: IRT-NTTNET-ID last-modified: 2011-02-28T12:36:44Z source: APNIC
IP address ranges, or netblocks, are groups of related IP addresses. They are usually represented as a base IP address, followed by a slash, and then a netmask which represents how many IP addresses are contained within the netblock. This format is known as CIDR. You'll also sometimes see netblocks given as a start ip address, and an end ip address, or an ip address range.
Traffic works its way around the internet based on the routing table, which contains a list of networks and their associated netblocks.