2a05:9800:4::/48 - UK-IO-20150106
inet6num: 2a05,9800,,/29 netname: UK-IO-20150106 country: GB org: ORG-IUOL1-RIPE admin-c: NA4634-RIPE tech-c: NA4634-RIPE status: ALLOCATED-BY-RIR mnt-by: RIPE-NCC-HM-MNT mnt-by: EQUINIX-MNT mnt-lower: IOUK-MNTNER mnt-lower: EQUINIX-MNT mnt-routes: IOUK-MNTNER created: 2015-01-06T15,20,47Z last-modified: 2017-04-07T08,19,07Z source: RIPE organisation: ORG-IUOL1-RIPE org-name: IO UK One Limited org-type: LIR address: 13 Liverpool Rd. address: SL1 4PF address: Slough address: UNITED KINGDOM phone: +1-480-513-8500 e-mail: email@example.com mnt-ref: RIPE-NCC-HM-MNT mnt-ref: EQUINIX-MNT mnt-ref: IOUK-MNTNER mnt-by: RIPE-NCC-HM-MNT mnt-by: EQUINIX-MNT tech-c: NA4634-RIPE abuse-c: AC26368-RIPE created: 2015-01-06T09,43,47Z last-modified: 2017-04-07T08,19,07Z source: RIPE admin-c: SP14456-RIPE role: Network Administrator address: 13 Liverpool Rd. address: Slough address: SL1 4PF address: United Kingdom e-mail: firstname.lastname@example.org nic-hdl: NA4634-RIPE mnt-by: IOUK-MNTNER created: 2015-01-06T13,56,13Z last-modified: 2015-01-06T13,56,13Z 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.