inet6num: 2a01:728:108::/48 netname: ADISTA-JMD-V6 descr: Jean-Michel Dilly country: FR admin-c: JD377-RIPE tech-c: JD377-RIPE abuse-c: JA7994-RIPE notify: firstname.lastname@example.org notify: email@example.com mnt-by: RMI-MNT status: ASSIGNED mnt-irt: IRT-RMI created: 2015-04-27T11:36:23Z last-modified: 2018-07-31T14:45:55Z source: RIPE person: Jean-Michel DILLY address: 53 avenue d'Harcourt, 14000 Caen, France mnt-by: Jean-Michel-DILLY-MNT e-mail: firstname.lastname@example.org phone: +33972132296 nic-hdl: JD377-RIPE notify: email@example.com created: 2009-12-23T16:34:16Z last-modified: 2017-10-30T22:07:53Z source: RIPE route6: 2a01:728:108::/48 descr: JM Dilly origin: AS12395 mnt-by: RMI-MNT notify: firstname.lastname@example.org created: 2015-04-27T11:36:36Z last-modified: 2015-04-27T11:36:36Z source: RIPE
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.