OSPFv3 replaces OSPFv2 in IPv6 environments due to differences in the format of IPv6 addresses compared to the IPv4 addresses used in OSPFv2.

Here's a more detailed explanation of OSPFv3:

Scalability improvements

OSPFv3 has improved scalability compared to OSPFv2, making it more suitable for large and complex networks. OSPFv3 uses zone and area architecture, which helps divide the network into smaller areas to facilitate routing and decrease the amount of routing information each router must maintain.

OSPFv3 packet types

OSPFv3 uses different types of packets to carry out the routing process. Some of the important packages are:

• Hello (Hello): They are used for discovery and maintenance of OSPFv3 neighbors.
• Database Description (DD): Helps synchronize routing database between OSPFv3 routers.
• Link State Request (LSR): Used to request information about specific links from other routers.
• Link State Update (LSU): It is used to send link state information to other routers.
• Link State Acknowledgment (LSAck): Sent to confirm receipt of LSU packets.

Types of OSPFv3 areas

OSPFv3 maintains a hierarchical structure through the use of areas. The most common types of areas are:

• Backbone Area: This area is mandatory and must be present on any OSPFv3 network. It connects all OSPFv3 areas and is responsible for the interconnection between them.
• Regular Area (Standard Area): These areas are adjacent to the backbone area and may contain IPv6 subnets.
• Transit Area: It is a type of special area through which traffic from one area cannot pass directly to another area. There can only be one transit area in an OSPFv3 network.

Authentication

OSPFv3 supports authentication using different methods to ensure the security of routing information. Authentication methods include area authentication, message authentication, and IPsec authentication.

Routing Types

OSPFv3 uses two types of routing depending on network size and complexity:

• Intra-area routing: It refers to routing within the same area. Routers exchange link state information within the area to determine the shortest routes to subnets within that area.
• Inter-area routing: It refers to routing between different areas. Routers in the backbone area advertise routes learned from other areas through routing digests, allowing traffic to propagate from one area to another.

Metrics

Like OSPFv2, OSPFv3 uses metrics to determine the shortest paths to different networks on the network. The metric used in OSPFv3 is called “cost” and is based on the speed of the links. The lower the cost, the better the route. OSPFv3 uses a default value for the cost of each link type, but this value can be modified manually by the network administrator.

Routing Summary (Summary)

OSPFv3 allows the creation of routing digests in the backbone area to reduce the amount of routing information that is propagated in the network. These routing summaries represent entire networks and are used to simplify routing in smaller areas.

Types of networks

OSPFv3 supports several types of networks, including point-to-point networks, point-to-multipoint networks, and non-broadcast point-to-multipoint networks. Each type of network has its own method of forming neighbors and exchanging Hello packets.

Fast convergence

OSPFv3 is designed to achieve rapid convergence in the event of network topology changes, such as link failures or new links activated. Fast convergence ensures that the network quickly adapts to changes and finds optimal routes after any event.

Tipos the routers

OSPFv3 defines three types of routers based on their role in the area:

• Internal Router (Internal Router): An internal router has all its interfaces in the same OSPFv3 area.
• Border Router (Area Border Router – ABR): An ABR has interfaces in more than one OSPFv3 area, including the backbone area.

Border Router (Autonomous System Border Router – ASBR): An ASBR is a router that is responsible for exchanging routing information between OSPFv3 and other routing protocols external to OSPFv3, such as BGP (Border Gateway Protocol).