230 CHAPTER 16: IP R OUTING P ROTOCOL OPERATIONPerform the following configuration in Interface View:The usual packet format follows RFC1723 and nonstandard follows RFC2082.Configuring Split HorizonSplit horizon means that the route received through an interface will not be sentthrough this interface again. The split horizon algorithm can reduce the generation ofrouting loops, but in some special cases, split horizon must be disabled to obtaincorrect advertising at the cost of efficiency. Disabling split horizon has no effect onP2P connected links but is applicable on the Ethernet.Perform the following configuration in Interface View:By default, split horizon is enabled.Enabling RIP to Import Routes of Other ProtocolsRIP allows users to import the route information of other protocols into the routingtable.RIP can import routes from protocols including direct, static and OSPF.Perform the following configurations in RIP View.By default, RIP does not import the route information of other protocols.Configuring the Default Cost for the Imported RouteWhen you use the import-route command to import the routes of other protocols,you can specify their cost. If you do not specify the cost of the imported route, RIP willset the cost to the default cost, specified by the default cost parameter.Table 211 Setting RIP-2 Packet AuthenticationOperation CommandConfigure RIP-2 simple authentication key rip authentication-mode simplepassword_stringConfigure RIP-2 MD5 authentication withpacket type following RFC 1723rip authentication-mode md5 usualkey_stringConfigure RIP-2 MD5 authentication withpacket type following RFC 2082rip authentication-mode md5nonstandard key_string key_idCancel authentication of RIP-2 packet undo rip authentication-modeTable 212 Configuring Split HorizonOperation CommandEnable split horizon rip split-horizonDisable split horizon undo rip split-horizonTable 213 Enabling RIP to Import Routes of Other ProtocolsOperation CommandEnable RIP to import routes of otherprotocolsimport-route protocol [ cost value ] [route-policy route_policy_name ]Disable route imports from otherprotocolsundo import-route protocol
