AS13445 Cisco Webex LLC
2402:2500:6::/48 - WEBEXAPNIC
inet6num: 2402:2500::/32 netname: WEBEXAPNIC descr: WebEx Communications, Inc. APNIC network. country: SG org: ORG-WCI2-AP admin-c: NO49-AP tech-c: NO49-AP mnt-lower: MAINT-AP-WEBEX mnt-routes: MAINT-AP-WEBEX mnt-irt: IRT-WEBEXAPNIC-AP mnt-by: APNIC-HM status: ALLOCATED PORTABLE last-modified: 2017-12-01T13:03:11Z source: APNIC
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.