Static routing

小乔

Static routing

It refers to the routing information manually configured by the network administrator

一、Advantages of Static routing
1. There is no management overhead for the CPU of router
2. There is no extra bandwidth between routers
3. Administrators can choose to only allow access to specific networks, which increases security

二、Disadvantage of Static routing
1. The network administrator must understand the whole topology of the network to configure these routes correctly
2. If the network topology changes, the administrator should modify the routing table manually on all routers
3. Not suitable for large network

三、Static routing config
router（config）#ip route {destination_ network} {mask} {next-hop_ address or exit_ interface} {administrative_ distance} {permanent}
#administrative_ Distance: add this part of the command can be used to modify the management distance. The default value is any integer from 1 to 255. In combination with dynamic routing, it can be used as backup routing to prevent network congestion (static floating routing) when dynamic routing fails to work.
#Permanent: this command indicates that the route entry will be kept in the route table no matter what happens.

4、 Using show ip route to view routing table
Router#sh ip route
......
Gateway of last resort is 16.1.1.1 to network 0.0.0.0

   16.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
S     16.8.8.0/27 [1/0] via 16.2.2.2     #S--Static routing；[1/0] [AD/metric]
S     16.7.7.0/30 [1/0] via 16.2.2.2
C     16.2.2.0/30 is directly connected, fast Ethernet 0 / 0  #c means directly connected network; directly means directly connected network
C     16.1.1.0/30 is directly connected, Serial1/1

   172.16.0.0/30 is subnetted, 1 subnets
S     172.16.2.0 [1/0] via 16.2.2.2

   192.168.2.0/32 is subnetted, 1 subnets
C     192.168.2.1 is directly connected, Loopback1
S *  0.0.0/0 [1 / 0] via 16.1.1.1   # * indicates that this route entry is the default route (i.e. 0.0.0/0 any network, any mask network). In Cisco routing table, * is the default route. 0.0.0/0）。

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