注释 备份接口得配置要放在物理接口上而不是子接口上。一般不推荐使用此方法进行备份，因为很多广域网链路得问题不能体现在物理接口down掉上，并且在正常情况下会使备份接口处于禁用状态，这样会需要重新拨号，不能使用show isdn status等命令进行查看状态等问题。
13.5. 使用Dialer Watch
提问 使用思科得Dialer Watch特性来触发拨号备份
回答
Router1#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router1(config)#interface BRI0/0
Router1(config-if)#ip address 10.1.99.55 255.255.255.0
Router1(config-if)#encapsulation ppp
Router1(config-if)#dialer map ip 10.1.1.0 name dialhost broadcast 95551212
Router1(config-if)#dialer map ip 10.2.0.0 name dialhost broadcast 95551212
Router1(config-if)#dialer map ip 10.1.99.1 name dialhost broadcast 95551212
Router1(config-if)#dialer load-threshold 50 either
Router1(config-if)#dialer watch-group 1
Router1(config-if)#dialer-group 1
Router1(config-if)#isdn switch-type basic-ni
Router1(config-if)#isdn spid1 800555123400 5551234
Router1(config-if)#isdn spid2 800555123500 5551235
Router1(config-if)#ppp authentication chap
Router1(config-if)#ppp multilink
Router1(config-if)#exit
Router1(config)#router eigrp 55
Router1(config-router)#network 10.0.0.0
Router1(config-router)#exit
Router1(config)#username dialhost password cisco
Router1(config)#access-list 101 deny eigrp any any
Router1(config)#access-list 101 permit ip any any
Router1(config)#dialer-list 1 protocol ip list 101
Router1(config)#dialer watch-list 1 ip 10.2.0.0 255.255.0.0
Router1(config)#dialer watch-list 1 ip 10.1.1.0 255.255.255.0
Router1(config)#dialer watch-list 1 delay route-check initial 300
Router1(config)#dialer watch-list 1 delay disconnect 15
Router1(config)#end
Router1#更多内容请看PCdog.com--Cisco IOS技术手册 Cisco交换机 Cisco路由器配置手册专题
