inet6num: 2a04,a580,,/29 netname: IT-SINET-20140124 country: IT org: ORG-SSDV1-RIPE admin-c: PC12668-RIPE tech-c: PC12668-RIPE status: ALLOCATED-BY-RIR mnt-by: RIPE-NCC-HM-MNT mnt-by: PC11529-MNT mnt-routes: PC11529-MNT notify: email@example.com created: 2014-01-24T10,02,47Z last-modified: 2016-11-24T15,56,46Z source: RIPE organisation: ORG-SSDV1-RIPE org-name: SINET SRL org-type: LIR address: Viale del Lago, 22 address: 67038 address: Scanno address: ITALY phone: +393450871121 fax-no: +390864773333 e-mail: firstname.lastname@example.org mnt-ref: RIPE-NCC-HM-MNT mnt-ref: PC11529-MNT mnt-by: RIPE-NCC-HM-MNT mnt-by: PC11529-MNT abuse-c: SA31481-RIPE created: 2013-10-01T10,25,29Z last-modified: 2016-11-24T15,56,53Z source: RIPE person: Pace Cristian address: viale della Pineta, 13 phone: +39 0864 74610 e-mail: email@example.com nic-hdl: PC12668-RIPE mnt-by: PC11529-MNT created: 2013-10-29T18,08,12Z last-modified: 2013-10-29T18,08,12Z 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.