Open Shortest Path First support concepts

Before using i5/OS support in an OSPF networking environment, it is important to understand the requirements of an OSPF participant. This topic describes the OSPF concept of areas and interfaces, and identifies the i5/OS commands that configure these on your system.

OSPF uses a link-state algorithm to calculate and use the shortest distance between a central node and all other nodes in an OSPF networking environment. Each node describes and sends the state of its own links and the complete topology, or routing structure, created by it and all of its neighbor nodes.

The i5/OS OSPF support uses the OMPROUTED server to register the system as a node or participant in an OSPF network. Each OSPF node or route destination is in the format of a dotted decimal IPv4 or IPv6 address. The OMPROUTED server daemon conforms to UNIX standards and is POSIX compliant. It uses the TCP/IP protocols provided on the i5/OS platform to run the QTOOROUTE job in the QSYSWRK subsystem. The job supports both IPv4 and IPv6 operations.

OSPF concepts include areas and interfaces to routers that are defined within them. The OSPF protocol uses packet types for initial neighbor discovery, and to send and receive link-state advertisements (LSAs) throughout its network of IP addresses. It uses different kinds of routers and path types to support different types of networks. Before using i5/OS OSPF support, determine how to split an OSPF routing domain into areas and how to use other OSPF functions, such as area aggregation and LSAs.

The i5/OS support is different for IPv4 and IPv6, when using OSPF routing. This topic covers these differences and other important information like the use of an i5/OS line description to provide a TCP/IP OSPF interface.