2a03:d180:fffe::/48 - BG-ESO-20111102
inet6num: 2a03,d180,,/32 netname: BG-ESO-20111102 country: BG org: ORG-ESOE1-RIPE admin-c: IOTA-RIPE tech-c: IOTA-RIPE status: ALLOCATED-BY-RIR mnt-by: RIPE-NCC-HM-MNT mnt-by: NOC-ESO mnt-routes: NOC-ESO notify: firstname.lastname@example.org created: 2011-11-02T13,15,20Z last-modified: 2017-06-06T11,13,54Z source: RIPE organisation: ORG-ESOE1-RIPE org-name: Electroenergien Sistemen Operator EAD org-type: LIR address: 201, Tsar Boris III blvd. address: 1618 address: Sofia address: BULGARIA phone: +35929691370 e-mail: email@example.com mnt-ref: NOC-ESO mnt-ref: RIPE-NCC-HM-MNT mnt-by: RIPE-NCC-HM-MNT mnt-by: NOC-ESO created: 2014-10-09T13,56,18Z abuse-mailbox: firstname.lastname@example.org abuse-c: ESOA-RIPE last-modified: 2017-01-05T20,10,24Z source: RIPE person: Ioakim Tanev address: Sofia, Bulgaria address: 201, Tsar Boris III blvd. phone: +359 2 9691 370 e-mail: email@example.com nic-hdl: IOTA-RIPE mnt-by: NOC-ESO created: 2015-07-03T11,14,32Z last-modified: 2017-01-05T19,50,05Z source: RIPE route6: 2a03,d180,,/32 descr: ESO-IPv6 origin: AS13172 mnt-by: NOC-ESO created: 2011-11-14T12,14,37Z last-modified: 2015-07-10T07,44,07Z 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.