Final answer:
NDP finds routers by sending Neighbor Solicitation messages. It uses ICMPv6 to identify routers on IPv6 networks by communicating with the all-routers multicast address.
Step-by-step explanation:
Neighbor Discovery Protocol (NDP) finds routers on a network by using Neighbor Solicitation messages. NDP is a protocol used in Internet Protocol Version 6 (IPv6) networks to discover and determine the reachability of neighbors on the same link or layer 2 domain. It operates in the link-local scope and uses ICMPv6 messages to accomplish various tasks, including router discovery. The process involves sending Neighbor Solicitation messages to the all-routers multicast address, where all IPv6 routers on the local link listen. Routers respond to these solicitations with Router Advertisement messages, allowing the host to identify and learn the routers present on the network.