User`s guide

OSPF Overview
8-2 Configuring OSPF
routerbeingaddedtothenetwork,OSPFusestheShortestPathFirst(SPF)algorit h m(also
referredtoastheDijkstraalgorithm)tocalculatenewroutes.
OSPF Terminology
Table 8‐1defineskeyterminologyusedinOSPFconfiguration.
Supported Functions
MatrixDFESeriesandN‐SAdevicessupportthefollowingOSPFfunctions:
• Authentication:SimplepasswordandMD5authenticationmethodsaresupportedwithinan
area.
•OneOSPFInstancepermodule:UsedtoenableordisableOSPF.
•InterfaceParameters:Parametersthatcanbeconfiguredincludeinterfaceoutputcost,
retransmissioninterval,interfacetransitdelay,router
priority,routerdeadandhellointervals,
andauthentication.
•RIPRouteRedistribution:RouteslearnedbywayoftheRIP routingprotocol,aswellasstatic
andconnectedroutes,canberedistributedintoOSPF.OSPFroutescanalsoberedistributed
intoRIP.
• Definitionofstubareas
• DefinitionofNotSoStubbyAreas(NSSAs)
•Static
multi‐pathforwarding
•Virtuallinks
Table 8-1 OSPF Terms and Definitions
Term Definition
ABR Area Border Router located on the border of one or more OSPF area
connecting those areas to the backbone network.
AS Autonomous System — A collection of networks under a common
administration sharing a common routing strategy
ASBR Autonomous System Boundary Router — located between an OSPF
Autonomous System and a non-OSPF network
ASE Autonomous System External destination
LSA Link State Advertisement — Broadcast packet containing information about
neighbors and path costs used by receiving routers to maintain routing tables
LSDB Link State Database
NSSA Not-So-Stubby Area — A form of stub area that allows some advertisements
from external routes, used when an OSPF network is connected to multiple
non-OSPF routing domains
Stub area Area that carries a default route, intra-area routes, and inter-area routes, but
does not carry external routes
Virtual link Logical connection between an OSPF backbone and non-backbone area.