OSPFv3 Overview
Open Shortest Path First (OSPF) is a
link-state routing protocol. Each OSPF device originates link-state advertisement
(LSA)
packets to describe its link information. These LSAs are flooded throughout the
OSPF area.
The flooding algorithm ensures that every device in the area has an identical database.
Each
device in the area then calculates a Shortest Path Tree (SPT) that shows the shortest
distance to every other device in the area, using the topology information in the
Link State
database.
IPv6 supports OSPF Version 3 (OSPFv3), which functions similarly to OSPFv2, the version that IPv4 supports, except for the following enhancements:
- Support for IPv6 addresses and prefixes.
- Ability to configure several IPv6 addresses on a device interface. (While OSPFv2 runs per IP subnet, OSPFv3 runs per link. In general, you can configure several IPv6 addresses on a router interface, but OSPFv3 forms one adjacency per interface only, using the link local address of the interface as the source for OSPF protocol packets. On virtual links, OSPFv3 uses the global IP address as the source. OSPFv3 imports all or none of the address prefixes configured on a router interface. You cannot select the addresses to import.)
- Ability to run one instance of OSPFv2 and one instance of OSPFv3 concurrently on a link.
- Support for IPv6 link-state advertisements (LSAs).