Lenovo Flex System Fabric CN4093 User Manual

© Copyright Lenovo 2017 Chapter 30: OSPF 477
Virtual Links
Usually,allareasinanOSPFASarephysicallyconnectedtothebackbone. Insome
caseswherethisisnotpossible,youcanuseavirtuallink.Virtuallinksarecreated
toconnectoneareatothebackbonethroughanothernon‐backbonearea(see
Figure 47onpage 468).
Theareawhich
containsavirtuallinkmustbeatransitareaandhavefullrouting
information.VirtuallinkscannotbeconfiguredinsideastubareaorNSSA.The
areatypemustbedefinedastransitusingthefollowingcommand:
Thevirtuallinkmustbeconfiguredontheroutingdevicesat eachendpointof
the
virtuallink,thoughtheymaytraversemultipleroutingdevices.Toconfigurea
CN4093asoneendpointofavirtuallink,usethefollowingcommand:
where<linknumber>isavaluebetween 1and3,<areaindex>istheOSPFareaindex
ofthetransitarea,and<routerID>isthe
IPaddressofthevirtualneighbor(nbr),
theroutingdeviceatthetargetendpoint.AnotherrouterIDisneededwhen
configuringavirtuallinkintheotherdirection.ToprovidetheCN4093witha
routerID,seethefollowingsection,RouterID.
ForadetailedconfigurationexampleonVirtualLinks,see
“Example 2:Virtual
Links”onpage 485.
Router ID
RoutingdevicesinOSPFareasareidentifiedbyarouterID,expressedinIP
addressformat.TherouterIDisnotrequiredtobepartofanyIPinterfacerangeor
inanyOSPFarea,andmayevenusetheCN4093loopbackinterface(see
“LoopbackInterfacesinOSPF”onpage 481).
The
routerIDcanbeconfiguredinoneofthefollowingtwoways:
 Dynamically(t hedefault)—OSPFprotocolconfigurestherouterIDasthelowest
IPloopbackinterfaceIPaddress,ifavailable,orelsethelowestIPinterfaceIP
address,ifavailable.Oncedynamicallyconfigured,therouterIDdoesnotnor‐
mallyundergofurtherupdates.
 Statically—Usethefollowingcommandtomanually configuretherouterID:
TochangetherouterIDfromstatictodynamic,settherouterIDto0.0.0.0,savethe
configuration,andreboottheCN4093.Toview therouterID,enter:
CN 4093(config-router-ospf)# area <areaindex> type transit
CN 4093(config-router-ospf)# area-virtual-link <linknumber> neighbor-router
<routerID>
CN 4093(config-router-ospf)# ip router-id <IPv4address>
CN 4093(config-router-ospf)# show ip ospf

Lenovo Flex System Fabric CN4093 Specifications

General

Brand	Lenovo
Model	Flex System Fabric CN4093
Category	Switch
Language	English