[HCIA continuous update] working principle of static route and default route

How static routing and default routing work

Static routing

Static routing application scenarios

1、 Static routing is manually configured by the network administrator , Convenient configuration , Low system requirements , Suitable for small networks with simple and stable topology

2、 The disadvantage is that it can't adapt to the change of network topology automatically , Manual intervention required .

3、RTA The forwarding destination address on belongs to 2.1.1.0/24 Message of , In the case of no direct connection, there is only . At this time, you can manually configure the route , send RAT Go to 20.1.1.0/24 The message of the network segment is handed over to the next hop 10.0.0.2 forward

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Static routing configuration

Associate next IP The way

ip route-static ip-address {mask|mask-lengrh} nexthop-address

How to associate the interface

ip route-static ip-address {mask|mask-length} interface-type interface-number

Associate the outbound interface with the next hop IP The way

ip route-static ip-address {mask|mask-length} interface-type interface-number [nexthop-address]

When creating a static route , You can specify both the interface and the next hop . For different outgoing interface types , You can also specify only the next hop

For point-to-point interfaces ( Such as serial port ), Just specify the outgoing interface .

For broadcast interface （ Such as Ethernet interface ） and VT(Virtual-yerplate) Interface , The next hop must be specified

Default route

1、 The default route is a special route , The route used when the message does not find a matching specific route table item in the route table . If the destination address of the message cannot match any destination address in the routing table , Then the message will be forwarded by selecting the default route .

2、 The default route is in the form of... In the routing table 0.0.0.0/0, The default route is also called the default route