27.1.8 Notes

<Structure of this section>

(1) Notes on Router ID

The OSPFv3 protocol uses a router ID to identify routers when constructing the network topology.

The protocol cannot select paths correctly if the same router ID is set for multiple routers in the network design. To prevent problems, assign a unique router ID to each router in the network design.

When one router connects to more than one OSPFv3 domain, using the same router ID in every domain does not present a problem.

(2) Notes on Route Redistribution and Learn Filters

The OSPFv3 protocol advertises every LSA it learns from neighboring routers to its other neighbors.

You cannot use redistribution filtering to prevent the advertisement of routes learned by OSPFv3 within the same domain. Also, when using the route summarization functionality (the ipv6 summary-address command) to summarize OSPFv3 routes, you cannot prevent LSA within the same domain even if you configure route filtering to exclude summarization source routes from advertisement.

You can use the distribute-list in command to suppress learning of external AS routes that match the filter conditions. However, you cannot prevent OSPFv3 from learning and advertising LSAs. Therefore, OSPFv3 will also advertise the routes it has not itself learned.

(3) Notes on using the multi-backbone facility

(a) Notes on using multi-backbone

In an environment that divides the network into more than one OSPFv3 domain, the advantages of OSPFv3 such as cost-based route selection and the avoidance of routing loops are lost when the selection and distribution of routes crosses OSPFv3 domain boundaries. When building a new network, if there is no need to divide the network into more than one OSPFv3 domain, we recommend that you design it to operate as a single OSPFv3 network.

(b) Notes on configuring multiple domains

If you need to advertise the switch address to more than one OSPFv3 domain, advertise it as an OSPFv3 external AS route. You cannot assign an interface to more than one OSPFv3 domain in the switch configuration.

(4) OSPFv3 Limitations and Restrictions

The Switch conforms to RFC 2740 (OSPF for IPv6) but does not support the following functions due to software limitations:

Route selection based on forwarding addresses for external AS routes
Non-broadcast (NBMA) network