AS15290 Allstream Corp.
2001:4c8::/33 - MTSALR-IPV6-1
V6NetHandle: NET6-2001-4C8-1 OrgID: ACCA-2 Parent: NET6-2001-400-0 NetName: MTSALR-IPV6-1 NetRange: 2001:4C8:: - 2001:4C8:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF NetType: allocation RegDate: 2004-12-01 Updated: 2012-03-02 TechHandle: AIA2-ARIN Source: ARIN OrgID: ACCA-2 OrgName: Allstream Corp. CanAllocate: Street: 200 Wellington Street West Street: 16th Floor City: Toronto State/Prov: ON Country: CA PostalCode: M5V-3G2 RegDate: 2003-07-10 Updated: 2017-02-10 ReferralServer: rwhois://rwhois.allstream.com:4321 OrgTechHandle: ZIE-ARIN OrgTechHandle: ALVAR41-ARIN OrgAdminHandle: ZIE-ARIN OrgAbuseHandle: NETWO5000-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.