A link-local unicast address is used as the source address in Open Shortest Path First version 3 (OSPFv3) packets on all OSPF interfaces except virtual links. Linklocal unicast addresses use the FE80::/10 address range; these addresses begin with the hexadecimal characters FE80 through FEBF. Because link-local addresses are unique only on the local segment, link-local addresses are not routable. An IPv6capable host typically creates a link-local unicast address automatically at startup.
OSPFv3 virtual link interfaces must use a global scope IPv6 address as the source address for OSPFv3 packets. If a router has one or more virtual links configured, it includes the global scope IPv6 address in the LSA, sets the LA-bit in the PrefixOptions field, configures the PrefixLength field to a value of 128, and sets the Metric field to a value of 0. Global aggregatable unicast addresses use the 2000::/3 address range; these addresses begin with the hexadecimal characters 2000 through 3FFF. Global aggregatable unicast address prefixes are distributed by the Internet Assigned Numbers Authority (IANA) and are globally routable over the Internet.