1-6Route RecursionThe nexthops of some BGP routes (except eBGP routes) and static routes configured with nexthopsmay not be directly connected. To forward the packets, the outgoing interface to reach the nexthop mustbe available. Route recursion is used to find the outgoing interface based on the nexthop information ofthe route. Link-state routing protocols, such as OSPF and IS-IS, do not need route recursion becausethey obtain nexthop information through route calculation.Sharing of Routing InformationAs different routing protocols use different routing algorithms to calculate routes, they may find differentroutes. In a large network with multiple routing protocols, it is required for routing protocols to share theirrouting information. Each routing protocol has its own route redistribution mechanism. For detailedinformation, refer to the IP Routing Volume.Configuring a Router IDSome routing protocols use a router ID to identify a device. You can configure a global router ID for adevice. If no router ID is configured for a protocol, the global router ID is used.To do… Use the command… RemarksEnter system view system-view —Configure a router ID router id router-id OptionalNot configured by default.Displaying and Maintaining a Routing TableTo do… Use the command… RemarksDisplay brief information aboutthe active routes in the routingtabledisplay ip routing-table[ vpn-instance vpn-instance-name ][ verbose | | { begin | exclude |include } regular-expression ]Available in any viewDisplay information aboutroutes to the specifieddestinationdisplay ip routing-table ip-address[ mask-length | mask ][ longer-match ] [ verbose ]Available in any viewDisplay information aboutroutes with destinationaddresses in the specifiedrangedisplay ip routing-table ip-address1{ mask-length | mask } ip-address2{ mask-length | mask } [ verbose ]Available in any viewDisplay information aboutroutes permitted by an IPv4basic ACLdisplay ip routing-table aclacl-number [ verbose ] Available in any viewDisplay routing informationpermitted by an IPv4 prefix listdisplay ip routing-table ip-prefixip-prefix-name [ verbose ] Available in any viewDisplay routes of a routingprotocoldisplay ip routing-table protocolprotocol [ inactive | verbose ] Available in any view
