Cisco ODR配置示例

静态路由的缺点是，必须手工配置，同时在网络拓扑变化后需要手工更新；动态路由的缺点是，它们需要占用网络带宽和路由器资源。在包含数百个分支站点的中央-分支网络，采用静态路由时配置工作量将非常大，而采用动态路由时将占用大量的资源。

在这种情况下，我们采用第三种方式——按需路由（ODR,On Demand Routing）。ODR是Cisco的私有协议，它使用CDP在分支路由器和中央路由器之间传输网络信息。它的优点是，比动态路由协议开销小得多，比静态路由协议配置量少得多。而它的缺点就是，只适合于中央-分支拓扑。

在中央路由器的全局模式下使用router odr命令来启用ODR。

下面是ODR配置示例：

R1配置如下：

R1#sh run     

Building configuration...

Current configuration : 1289 bytes

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

service password-encryption

hostname R1

boot-start-marker

boot-end-marker

enable secret 5 $1$xGcB$Oir1JjPzZdoLL4wxA7kPH1

aaa new-model

aaa authentication login default local

aaa session-id common

no ip icmp rate-limit unreachable

ip cef

no ip domain lookup

username cisco password 7 091D1C5A4D5041

ip tcp synwait-time 5

interface FastEthernet0/0

 ip address 192.168.1.1 255.255.255.252

 duplex auto

 speed auto

interface FastEthernet0/1

 ip address 192.168.1.5 255.255.255.252

 duplex auto

 speed auto

interface Serial1/0

 no ip address

 shutdown

 serial restart-delay 0

interface Serial1/1

 no ip address

 shutdown

 serial restart-delay 0

interface Serial1/2

 no ip address

 shutdown

 serial restart-delay 0

interface Serial1/3

 no ip address

 shutdown

 serial restart-delay 0

router odr                //配置ODR

no ip http server

no ip http secure-server

no cdp log mismatch duplex

control-plane

gatekeeper

shutdown

line con 0

 exec-timeout 0 0

 privilege level 15

 logging synchronous

 no exec

 stopbits 1

line aux 0

 exec-timeout 0 0

 privilege level 15

 logging synchronous

 stopbits 1

line vty 0 4

end

R2的配置如下：

R2#sh run

Building configuration...

Current configuration : 1319 bytes

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

service password-encryption

hostname R2

boot-start-marker

boot-end-marker

enable secret 5 $1$AOeH$KIuGrBL.TNS1Iwe0Kt8Bd0

aaa new-model

aaa authentication login default local

aaa session-id common

no ip icmp rate-limit unreachable

ip cef

no ip domain lookup

username cisco password 7 00554155500E5D

ip tcp synwait-time 5

interface Loopback0

 ip address 2.2.2.2 255.255.255.255

interface FastEthernet0/0

 ip address 192.168.1.2 255.255.255.252

 duplex auto

 speed auto

interface FastEthernet0/1

 no ip address

 shutdown

 duplex auto

 speed auto

interface Serial1/0

 no ip address

 shutdown

 serial restart-delay 0

interface Serial1/1

 no ip address

 shutdown

 serial restart-delay 0

interface Serial1/2

 no ip address

 shutdown

 serial restart-delay 0

interface Serial1/3

 no ip address

 shutdown

 serial restart-delay 0

no ip http server

no ip http secure-server

no cdp log mismatch duplex

control-plane

gatekeeper

shutdown

line con 0

 exec-timeout 0 0

 privilege level 15

 logging synchronous

 no exec

 stopbits 1

line aux 0

 exec-timeout 0 0

 privilege level 15

 logging synchronous

 stopbits 1

line vty 0 4

end

R3的配置如下：

R3#sh run

Building configuration...

*May  5 19:44:13.907:%SYS-5-CONFIG_I: Configured from console by console

Current configuration : 1319 bytes

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

service password-encryption

hostname R3

boot-start-marker

boot-end-marker

enable secret 5 $1$nkGN$k3DeFEbRxkr8ILTnGTpDu/

aaa new-model

aaa authentication login default local

aaa session-id common

no ip icmp rate-limit unreachable

ip cef

no ip domain lookup

username cisco password 7 075E731F1A5C4F

ip tcp synwait-time 5

interface Loopback0

ip address 3.3.3.3 255.255.255.255

interface FastEthernet0/0

 no ip address

 shutdown

 duplex auto

 speed auto

interface FastEthernet0/1

 ip address 192.168.1.6 255.255.255.252

 duplex auto

 speed auto

interface Serial1/0

 no ip address

 shutdown

 serial restart-delay 0

interface Serial1/1

 no ip address

 shutdown

 serial restart-delay 0

interface Serial1/2

 no ip address

 shutdown

 serial restart-delay 0

interface Serial1/3

 no ip address

 shutdown

 serial restart-delay 0

no ip http server

no ip http secure-server

no cdp log mismatch duplex

control-plane

gatekeeper

shutdown

line con 0

 exec-timeout 0 0

 privilege level 15

 logging synchronous

 no exec

 stopbits 1

line aux 0

 exec-timeout 0 0

 privilege level 15

 logging synchronous

 stopbits 1

line vty 0 4

end

用R2去ping R3，测试连通性：

R2#ping 3.3.3.3

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 60/62/64ms

查看R1的路由表：

R1#sh ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

       D - EIGRP, EX - EIGRPexternal, O - OSPF, IA - OSPF inter area

       N1 - OSPF NSSA externaltype 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type1, E2 - OSPF external type 2

       i - IS-IS, su - IS-ISsummary, L1 - IS-IS level-1, L2 - IS-IS level-2

       ia - IS-IS inter area,* - candidate default, U - per-user static route

       o - ODR, P - periodicdownloaded static route

Gateway of last resort is not set

     2.0.0.0/32 is subnetted,1 subnets

o       2.2.2.2 [160/1] via192.168.1.2, 00:00:22, FastEthernet0/0

     3.0.0.0/32 is subnetted,1 subnets

o       3.3.3.3 [160/1] via192.168.1.6, 00:00:27, FastEthernet0/1

     192.168.1.0/30 issubnetted, 2 subnets

C       192.168.1.0 isdirectly connected, FastEthernet0/0

C       192.168.1.4 isdirectly connected, FastEthernet0/1

查看R2的路由表：

R2#sh ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

       D - EIGRP, EX - EIGRPexternal, O - OSPF, IA - OSPF inter area

       N1 - OSPF NSSA externaltype 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type 1, E2 - OSPFexternal type 2

       i - IS-IS, su - IS-ISsummary, L1 - IS-IS level-1, L2 - IS-IS level-2

       ia - IS-IS inter area,* - candidate default, U - per-user static route

       o - ODR, P - periodicdownloaded static route

Gateway of last resort is 192.168.1.1 to network 0.0.0.0

     2.0.0.0/32 is subnetted,1 subnets

C       2.2.2.2 is directlyconnected, Loopback0

     192.168.1.0/30 issubnetted, 1 subnets

C       192.168.1.0 isdirectly connected, FastEthernet0/0

o*   0.0.0.0/0 [160/1] via 192.168.1.1, 00:00:16, FastEthernet0/0

查看R3的路由表：

R3#sh ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

       D - EIGRP, EX - EIGRPexternal, O - OSPF, IA - OSPF inter area

       N1 - OSPF NSSA externaltype 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type1, E2 - OSPF external type 2

       i - IS-IS, su - IS-ISsummary, L1 - IS-IS level-1, L2 - IS-IS level-2

       ia - IS-IS inter area,* - candidate default, U - per-user static route

       o - ODR, P - periodicdownloaded static route

Gateway of last resort is 192.168.1.5 to network 0.0.0.0

     3.0.0.0/32 is subnetted,1 subnets

C       3.3.3.3 is directlyconnected, Loopback0

     192.168.1.0/30 issubnetted, 1 subnets

C       192.168.1.4 isdirectly connected, FastEthernet0/1

o*   0.0.0.0/0 [160/1] via 192.168.1.5, 00:00:45, FastEthernet0/1

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