inetnum: 2800:381::/32 status: allocated aut-num: N/A owner: Telefonica de Argentina ownerid: AR-TEAR7-LACNIC responsible: José Luis Pérez Elias address: AV. ING. HUERGO, 723, GERENCIA DE REQUERIMIENTOS JUDICIALES address: 1065 - Buenos Aires - CF country: AR phone: +54 8102220102  owner-c: TEA tech-c: TEA abuse-c: TEA created: 20130111 changed: 20130111 nic-hdl: TEA person: Telefonica de Argentina e-mail: tasamail.ar@TELEFONICA.COM address: AV. ING. HUERGO, 723, address: 1065 - Capital Federal - BA country: AR phone: +54 11 43335000  created: 20030618 changed: 20110603
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.