Step 17. Loop avoidance in multi-area OSPF topology¶
Goals¶
[explanation]
Configuration¶
This step uses the following network:
network OSPF_LoopAvoidance
{
@display("bgb=692,488");
submodules:
configurator: Ipv4NetworkConfigurator {
@display("p=62.18875,63.635002");
}
visualizer: IntegratedCanvasVisualizer {
@display("p=195.24374,63.635002");
}
scenarioManager: ScenarioManager {
@display("p=357.22375,63.635002");
}
R1: Router {
@display("p=218,179");
}
R2: Router {
@display("p=474,179");
}
R3: Router {
@display("p=349,297");
}
R4: Router {
@display("p=474,411");
}
R5: Router {
@display("p=218,411");
}
switch1: EtherSwitch {
@display("p=72,177");
}
switch2: EtherSwitch {
@display("p=619,177");
}
switch3: EtherSwitch {
@display("p=250,296");
}
switch4: EtherSwitch {
@display("p=619,410");
}
switch5: EtherSwitch {
@display("p=72,410");
}
switch6: EtherSwitch {
@display("p=349,410");
}
connections:
switch1.ethg++ <--> Eth100M <--> R1.ethg++;
R2.ethg++ <--> Eth100M <--> R3.ethg++;
R2.ethg++ <--> Eth100M <--> switch2.ethg++;
R5.ethg++ <--> Eth100M <--> switch5.ethg++;
R3.ethg++ <--> Eth100M <--> R4.ethg++;
R3.ethg++ <--> Eth100M <--> R5.ethg++;
R5.ethg++ <--> Eth100M <--> R1.ethg++;
R4.ethg++ <--> Eth100M <--> R2.ethg++;
switch4.ethg++ <--> Eth100M <--> R4.ethg++;
R1.ethg++ <--> Eth100M <--> R2.ethg++;
switch3.ethg++ <--> Eth100M <--> R3.ethg++;
switch6.ethg++ <--> Eth100M <--> R3.ethg++;
}
The configuration in omnetpp.ini is the following:
[Config Step17]
description = "Loop avoidance in multi-area OSPF topology"
network = OSPF_LoopAvoidance
*.configurator.config = xml("<config> \
<interface hosts='R1' names='eth0' address='10.0.0.9' netmask='255.255.255.252' /> \
<interface hosts='R1' towards='R2' address='10.0.0.5' netmask='255.255.255.252' /> \
<interface hosts='R1' towards='R5' address='10.0.0.1' netmask='255.255.255.252' /> \
\
<interface hosts='R2' names='eth1' address='10.0.0.21' netmask='255.255.255.252' /> \
<interface hosts='R2' towards='R1' address='10.0.0.6' netmask='255.255.255.252' /> \
<interface hosts='R2' towards='R3' address='10.0.0.13' netmask='255.255.255.252' /> \
<interface hosts='R2' towards='R4' address='10.0.0.17' netmask='255.255.255.252' /> \
\
<interface hosts='R3' names='eth3' address='10.0.0.33' netmask='255.255.255.252' /> \
<interface hosts='R3' names='eth4' address='10.0.0.37' netmask='255.255.255.252' /> \
<interface hosts='R3' towards='R2' address='10.0.0.14' netmask='255.255.255.252' /> \
<interface hosts='R3' towards='R5' address='10.0.0.29' netmask='255.255.255.252' /> \
<interface hosts='R3' towards='R4' address='10.0.0.25' netmask='255.255.255.252' /> \
\
<interface hosts='R4' names='eth2' address='10.0.0.41' netmask='255.255.255.252' /> \
<interface hosts='R4' towards='R2' address='10.0.0.18' netmask='255.255.255.252' /> \
<interface hosts='R4' towards='R3' address='10.0.0.26' netmask='255.255.255.252' /> \
\
<interface hosts='R5' names='eth0' address='10.0.0.45' netmask='255.255.255.252' /> \
<interface hosts='R5' towards='R1' address='10.0.0.2' netmask='255.255.255.252' /> \
<interface hosts='R5' towards='R3' address='10.0.0.30' netmask='255.255.255.252' /> \
\
<route hosts='host*' destination='*' netmask='0.0.0.0' interface='eth0' /> \
</config>")
*.R*.ospf.ospfConfig = xmldoc("ASConfig_Area_Loop.xml")
The OSPF configuration:
<?xml version="1.0"?>
<OSPFASConfig xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="OSPF.xsd">
<!-- Areas -->
<Area id="0.0.0.0">
<AddressRange address="R1>R2" mask="R1>R2" />
<AddressRange address="R2>R1" mask="R2>R1" />
</Area>
<Area id="0.0.0.1">
<AddressRange address="R1>R5" mask="R1>R5" />
<AddressRange address="R1>switch1" mask="R1>switch1" />
<AddressRange address="R5>R1" mask="R5>R1" />
<AddressRange address="R5>R3" mask="R5>R3" />
<AddressRange address="R5>switch5" mask="R5>switch5" />
<AddressRange address="R3>R5" mask="R3>R5" />
<AddressRange address="R3>switch3" mask="R3>switch3" />
</Area>
<Area id="0.0.0.2">
<AddressRange address="R2>switch2" mask="R2>switch2" />
<AddressRange address="R2>R4" mask="R2>R4" />
<AddressRange address="R2>R3" mask="R2>R3" />
<AddressRange address="R4>switch4" mask="R4>switch4" />
<AddressRange address="R4>R2" mask="R4>R2" />
<AddressRange address="R4>R3" mask="R4>R3" />
<AddressRange address="R3>R2" mask="R3>R2" />
<AddressRange address="R3>R4" mask="R3>R4" />
<AddressRange address="R3>switch6" mask="R3>switch6" />
</Area>
<!-- Routers -->
<Router name="R1" RFC1583Compatible="true">
<BroadcastInterface ifName="eth0" areaID="0.0.0.1" interfaceMode="Passive" />
<BroadcastInterface ifName="eth1" areaID="0.0.0.1" />
<BroadcastInterface ifName="eth2" areaID="0.0.0.0" />
</Router>
<Router name="R2" RFC1583Compatible="true">
<BroadcastInterface ifName="eth1" areaID="0.0.0.2" interfaceMode="Passive" />
<BroadcastInterface ifName="eth0" areaID="0.0.0.2" />
<BroadcastInterface ifName="eth2" areaID="0.0.0.2" />
<BroadcastInterface ifName="eth3" areaID="0.0.0.0" />
</Router>
<Router name="R3" RFC1583Compatible="true">
<BroadcastInterface ifName="eth0" areaID="0.0.0.2" />
<BroadcastInterface ifName="eth1" areaID="0.0.0.2" />
<BroadcastInterface ifName="eth2" areaID="0.0.0.1" />
<BroadcastInterface ifName="eth3" areaID="0.0.0.1" interfaceMode="Passive" />
<BroadcastInterface ifName="eth4" areaID="0.0.0.2" interfaceMode="Passive" />
</Router>
<Router name="R4" RFC1583Compatible="true">
<BroadcastInterface ifName="eth0" areaID="0.0.0.2" />
<BroadcastInterface ifName="eth1" areaID="0.0.0.2" />
<BroadcastInterface ifName="eth2" areaID="0.0.0.2" interfaceMode="Passive" />
</Router>
<Router name="R5" RFC1583Compatible="true">
<BroadcastInterface ifName="eth0" areaID="0.0.0.1" interfaceMode="Passive" />
<BroadcastInterface ifName="eth1" areaID="0.0.0.1" />
<BroadcastInterface ifName="eth2" areaID="0.0.0.1" />
</Router>
</OSPFASConfig>