inetnum: 2001:13c8::/32 status: assigned aut-num: N/A owner: EMPRESA DE TELECOMUNICACIONES DE CUBA S.A. (IXP CUBA) ownerid: CU-CUBA-LACNIC responsible: Rafael López Guerra address: Ave. Independencia y 19 Mayo, s/n, address: 10600 - La Habana - CH country: CU phone: +53 7 574242  owner-c: JOQ tech-c: JOQ abuse-c: JEM52 created: 20050818 changed: 20170313 nic-hdl: JEM52 person: Jesus Martimez e-mail: abuse@ETECSA.CU address: 3ra Ave , Edif Beiging, Miramar, Playa, , address: 10100 - Ciudad Habana - CH country: CU phone: +53 7 2668581  created: 20140610 changed: 20140610 nic-hdl: JOQ person: Rafael Lopez Guerra e-mail: nap@ETECSA.CU address: Ave. Independencia y 19 Mayo, MIC, s/n, address: 10600 - Ciudad Habana - CH country: CU phone: +53 7 8854242  created: 20030124 changed: 20120322
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.