Step 11. Configure an interface as NoOSPF¶
Goals¶
The goal of this step is to demonstrate the effect of excluding an interface from OSPF using
the NoOSPF interface mode.
Setting an interface to NoOSPF mode effectively removes it from OSPF processing. The
interface will not:
Send or receive OSPF packets
Form adjacencies
Be advertised in OSPF LSAs
This is equivalent to not including the interface in the OSPF configuration at all.
Configuration¶
This configuration is based on Step 3. Each router’s eth0 interface (the one facing the switch) is configured with
interfaceMode="NoOSPF".
The configuration in omnetpp.ini is the following:
[Config Step11]
description = "Configure an interface as NoOSPF"
extends = Step3
# setting interfaceMode to "NoOSPF" is equal to removing the interface from the XML config
*.R*.ospf.ospfConfig = xmldoc("ASConfig_NoOspf.xml")
The OSPF configuration:
<?xml version="1.0"?>
<OSPFASConfig xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="OSPF.xsd">
<!-- Routers -->
<Router name="R1" RFC1583Compatible="true">
<BroadcastInterface ifName="eth0" interfaceMode="NoOSPF" />
<PointToPointInterface ifName="ppp0" />
</Router>
<Router name="R2" RFC1583Compatible="true">
<BroadcastInterface ifName="eth0" interfaceMode="NoOSPF" />
<PointToPointInterface ifName="ppp0" />
</Router>
</OSPFASConfig>
Results¶
With the interface configured as NoOSPF:
The interface does not participate in OSPF at all.
No Hello packets are sent on the interface.
The network connected to this interface is not advertised in Router LSAs.
Other routers are unaware of this network and cannot route to it via OSPF.
This mode is useful when you want OSPF running on a router but need to exclude specific interfaces from OSPF processing, perhaps because they connect to non-OSPF networks or for security reasons.
Sources:
omnetpp.ini,
Network.ned,
ASConfig_NoOspf.xml
Discussion¶
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