User`s guide

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Configuration – Network > IP Routing / Forwarding > OSPF
Open Shortest Path First (OSPF) is an Interior Gateway Protocol (IGP) developed for IP
networks based on the shortest path first or link-state algorithm.
The router uses link-state algorithms to send routing information to all nodes in a network
by calculating the shortest path to each node based on a topography of the network
constructed by each node. Each router sends that portion of the routing table that describes
the state of its own links and the complete routing structure (network topography).
The advantage of the shortest path first algorithms is that they result in smaller, more
frequent update everywhere. They converge quickly, thus preventing such problems as
routing loops and Count-to-Infinity (where routers continuously increment the hop count to
a particular network). This makes for a stable network.
In order to use OSPF on the router, a valid configuration file must exist in the router’s filing
system.
Enable OSPF
When checked, this checkbox reveals the following parameters:
OSPF Configuration Filename
The file that contains the configuration data for OSPF is selected from this drop-down list.
The file should have a “.conf” extension.
Load Config file
When this button is clicked, the router attempts to load the file specified in the file selection
list box into the edit window below the button. The text in the window can be edited as
required.
Save Config File
When this button is clicked, the text in the edit window will be saved to the filename
specified in the drop-down list above. These three controls allow an OSPF configuration file
to be loaded, edited and saved.
Restart OSPF after configuration file is saved
When checked, this checkbox will cause the OSPF functions to restart once the edited
configuration file has been saved.
Restart OSPF if a fatal error occurs
When checked this checkbox will cause OSPF functioning to restart after a delay of 5
seconds if a fatal error occurs.
OSPF Tracing
In common with some of the other functionality of the router, OSPF supports some debug
functionality. The amount of information in the debug traces is controlled from this drop-
down list. The available levels are “Off”, “Low”, “Med” and “High”. Selecting “Off” disables
debug tracing.
Ignore MTU indications
All OSPF routers must have the same Maximum Transmitted Unit (MTU) and this value is
advertised in the OSPF packets. When checked, this checkbox will cause the router to ignore
received packets that have a MTU that differs from that of the router itself.