AS127 Jet Propulsion Laboratory
2001:1878:500::/40 - LN-V6-BLK-1
V6NetHandle: NET6-2001-1878-1 OrgID: LNET Parent: NET6-2001-1800-0 NetName: LN-V6-BLK-1 NetRange: 2001:1878:: - 2001:1878:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF NetType: allocation RegDate: 2003-09-25 Updated: 2012-03-20 TechHandle: LH-ORG-ARIN Source: ARIN OrgID: LNET OrgName: Los Nettos CanAllocate: Street: 3434 S. Grand Avenue Street: MS 2812/363 City: Los Angeles State/Prov: CA Country: US PostalCode: 90007-2812 RegDate: 1988-08-19 Updated: 2017-01-28 ReferralServer: rwhois://rwhois.ln.net:4321 OrgAbuseHandle: LNAT-ARIN OrgTechHandle: LH-ORG-ARIN OrgAdminHandle: CAN11-ARIN OrgNOCHandle: LNN1-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.