OSPF for IPv6 (OSPFv3)

OSPF for IPv6 modifies the existing OSPF for IPv4 to support IPv6. The fundamentals of OSPF for IPv4 remain unchanged. Some changes have been necessary to accommodate the increased address size of IPv6 and the changes in protocol semantics between IPv4 and IPv6. OSPF for IPv6 is defined in RFC 2740, which emphasizes the differences between OSPF for IPv4 and OSPF for IPv6. It contains a large number of references to the documentation of OSPF for IPv4, which makes it hard to read. This chapter tries to concatenate the two worlds to make the reading a little bit more comfortable. It starts with an overview of OSPF, including the area structure and external routes. After the overview, it opens up the protocol to get down to the implementation details: it starts with the OSPF message format, proceeds to the neighbor relationship, and finishes with the actual link state database and the calculation of the routing table.

Overview of OSPF for IPv6

OSPF for IPv4 (OSPFv2) is standardized in RFC 2328. In addition to this document, several extensions to OSPF have been defined. RFC 1584 describes IPv4 multicast extensions to OSPF. RFC 1587 adds not-so-stubby areas (NSSAs) to OSPF. RFC 2740 modifies OSPF to support the exchange of routing information for IPv6. OSPF for IPv6 has a new version number: version 3.

OSPF is classified as an IGP, which are used within autonomous systems. It was designed to overcome some of the limitations introduced by RIP, such as the small ...

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