V6NetHandle: NET6-2605-E900-1 OrgID: UPMC Parent: NET6-2600-1 NetName: UPMC-NET NetRange: 2605:E900:: - 2605:E900:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF NetType: allocation OriginAS: 122 Comment: http://www.upmc.com RegDate: 2011-09-06 Updated: 2012-03-20 Source: ARIN OrgID: UPMC OrgName: UPMC CanAllocate: Street: ISD Converged Technology Services Street: 200 Lothrop Street City: Pittsburgh State/Prov: PA Country: US PostalCode: 15213 RegDate: 1986-09-08 Updated: 2017-01-28 OrgTechHandle: UPMCT-ARIN OrgAdminHandle: SNYDE8-ARIN OrgAbuseHandle: INFOS7-ARIN OrgTechHandle: VULJA-ARIN Source: ARIN
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.