OSPFv3 overview

Open Shortest Path First version 3 (OSPFv3) supports IPv6 and complies with RFC 2740 (OSPF for IPv6). The term "router" in this chapter refers to both routers and Layer 3 switches.

OSPFv3 and OSPFv2 have the following similarities:

• 32-bits router ID and area ID

• Packets, including Hello, DD (Data Description), LSR (Link State Request), LSU (Link State Update), and LSAck (Link State Acknowledgment)

• Mechanism for finding neighbors and establishing adjacencies

• Mechanism for LSA flooding and aging

OSPFv3 and OSPFv2 have the following differences:

• OSPFv3 runs on a per-link basis, and OSPFv2 runs on a per-IP-subnet basis.

• OSPFv3 supports multiple instances per link, but OSPFv2 does not.

• OSPFv3 identifies neighbors by Router ID, and OSPFv2 by IP address.