H3C Technologies H3C S12500 Series Switches - Manual (Page 322)

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Configuring OSPFv3
OSPFv3 overview
Introduction to OSPFv3
Open Shortest Path First version 3 (OSPFv3) supports IPv6 and complies with RFC 5340 (OSPF for IPv6).
OSPFv3 and OSPFv2 have the following similarities:
• A 32-bit router ID and area ID
• Packets, including Hello, DD (Data Description), LSR (Link State Request), LSU (Link State Update),
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.
OSPFv3 packets
OSPFv3 has the following packet types: hello, DD, LSR, LSU, and LSAck. These packets have the same
packet header, which is different from the OSPFv2 packet header. The OSPFv3 packet header is only 16
bytes in length, and has no authentication field, but is added with an Instance ID field to support
multi-instance per link.
Figure 107 OSPFv3 packet header
Major fields for OSPFv3 packet header are as follows:
• Version #—Version of OSPF, which is 3 for OSPFv3.
• Type—Type of OSPFv3 packet; Types 1 to 5 are hello, DD, LSR, LSU, and LSAck.
• Packet length—Packet length in bytes, including header.
• Instance ID—Instance ID for a link.
• 0—Reserved. It must be 0.