AS12956 Telefonica International Wholesale Services II, S.L.U.
2800:240::/32 - MAB20
inetnum: 2800:240::/32 status: allocated owner: Telefónica International Wholesale Services Argentina S.A. city: Ciudad de Buenos Aires country: AR owner-c: MAB20 tech-c: MAB20 abuse-c: MAB20 inetrev: 2800:240::/32 nserver: GPLDNMIABR02.NET.TELEFONICAGLOBALSOLUTIONS.COM nserver: GPLDNMADPE02.NET.TELEFONICAGLOBALSOLUTIONS.COM created: 2008-06-13 changed: 2008-06-13 source: LACNIC
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.