Using the Matrix DFE Series or N-SA Device as a Router
7-2 Configuring IP
Example Scenario
ImagineyouareusingaMatrixDFESeriesorN‐SAswitchdevicethatisconfiguredfor10
VLANs.EachVLANincludes20physicalportswithoneclientoneachport,foratotalof200users
inthe10VLANs.Since,intheswitchingworld,the onlyusersthatcan
talktoeachotherarethe
usersinthesameVLAN,the20usersinVLAN3cantalktoeachother,buttheycan’ttalktothe
180otherusersintherestofyournetwork.
Thisiswhereroutinggetsinvolved.Fortraffictopassfromahost
inoneVLANtoahostin
anotherVLAN,theframesmustbeprocessedbyarouter,andthenforwardeddirectlytothe
destinationhost(ifthathosthappenstobedirectlyconnectedtotherouter),orforwardedtothe
nextrouterinthenetworkonthewaytothetarget
host.
Beforetrafficcanbeprocessedinthisway,arelationshipmust existbetweentherouterbeing
configuredandtheunderlyingswitch.Thisrelationshipisestablishedwiththe VLAN
configurationdescribedintheSampleConfigurationonpage 7‐8.EveryswitchedVLANinwhich
usersaretobegrantedaccessto
otherVLANs,musthaveacorrespondingrouter“interface
VLAN”configured.Theproceduresnecessarytocompletethisprocessaredetailedinthe
followingsections.
Preparing the Device for Router Mode
Atleastone modulemustbeconfiguredtorunasaroutertooperateaMatrixDFESeriesorN‐SA
deviceinroutermode.Oncethetasksdescribedin“Pre‐RoutingConfigurationTasks”(page 7‐3)
arecompleted,youcanfollowtheproceduresinthischaptertoperformbasicIP
interface
configurationtasks,andtosetthegeneral,non‐protocol‐specificroutingparametersrequiredfor
IProuting.
About Loopback and VLAN Interfaces
TheMatrixDFESeriesdeviceallowsyoutoconfigurebothVLANandloopbackinterfacesforIP
routing.LoopbackinterfacesaredifferentfromVLANroutinginterfacesbecausetheyallowyou
todisconnecttheoperationofroutingprotocolsfromnetworkhardwareoperation,improvingthe
reliabilityofIPconnections.Aloopbackinterfaceisalways
reachable.TheIPaddressassignedto
theloopbackinterfaceisusedastherouterID,whichhelpswhenrunningprotocolslikeOSPF,
becauseOSPFcanberunningevenwhentheoutboundinterfaceisdown.IPpacketsroutedtothe
loopbackinterfacearereroutedbacktotherouteroraccessserver
andprocessedlocally.
Foranexampleofhowaloopbackinterfacecouldbeusedinaroutingconfiguration,referto
Chapter 8,ConfiguringOSPF.
RoutinginterfaceconfigurationcommandsinthisguidewillconfigureeitheraVLANorloopback
interface,dependingonyourchoiceofparameters,asshowninTable 7‐1.
For
detailsonhowtoenableallrouterCLIconfigurationmodes,refertoTable 7‐2onpage 7‐3.
ForinformationonconfiguringtheOSPFroutingprotocol,refertoChapter 8.
ForinformationonconfiguringtheVRRProutingprotocol,refertoChapter 9.
Table 7-1 VLAN and Loopback Interface Configuration Modes
For Routing Interface
Type...
Enter (in Global Configuration
Mode)...
Resulting Prompt...
VLAN vlan vlan-id Matrix>Router1 (config-if(Vlan 1))#
Loopback loopback loopback-id Matrix>Router1 (config-if (Lpbk 1))#
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