我正在尝试configuration几条Cisco 1941路由。 这两个都是相同的路由器。 每个作为HWIC-1T（智能串行接口）和HWIC-3G-HSPA 3G接口。 这些路由器将被发送到远程站点。 我们连接到其中一个站点，但是如果远程站点A倒下，我们将失去与远程站点B的连接。
HWIC-1T是使用帧中继join两个远程站点的主要WAN接口
我们希望HWIC-3G-HSPA可用于从总部到远程站点B的直接连接，并且HWIC-3G-HSPA也可用于远程站点之间的帧中继closures（通常发生位）。
我初始尝试使用EIGRP做dynamic路由，但是在我的笔记本电脑实验室设置 – 笔记本电脑，我无法获得端到端连接。 后来我决定使用静态路由，并且已经有了端到端的连接，但是只能通过帧中继，而不是HWIC-3G-HSPA。
远程站点A的清理运行configuration：
version 15.1 service tcp-keepalives-in service tcp-keepalives-out service timestamps debug datetime msec service timestamps log datetime msec service password-encryption service udp-small-servers service tcp-small-servers ! hostname remoteA ! boot-start-marker boot-end-marker ! ! logging buffered 51200 warnings enable secret 5 censored ! no aaa new-model clock timezone wst 8 0 ! no ipv6 cef ip source-route ip cef ! ip domain name yourdomain.com multilink bundle-name authenticated ! chat-script gsm "" "ATDT*98*1#" TIMEOUT 30 "CONNECT" ! username admin privilege 15 secret 5 censored ! controller Cellular 0/1 ! interface Embedded-Service-Engine0/0 no ip address shutdown ! interface GigabitEthernet0/0 ip address 192.168.2.5 255.255.255.0 duplex auto speed auto ! interface GigabitEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/0/0 ip address 10.1.1.2 255.255.255.252 encapsulation frame-relay cdp enable frame-relay interface-dlci 16 frame-relay lmi-type ansi ! interface Cellular0/1/0 ip address negotiated encapsulation ppp dialer in-band dialer idle-timeout 2147483 dialer string gsm dialer-group 1 async mode interactive ppp chap hostname censored ppp chap password 7 censored cdp enable ! interface Cellular0/1/1 no ip address encapsulation ppp ! interface Dialer0 no ip address ! ip forward-protocol nd ! no ip http server no ip http secure-server ! ip route 0.0.0.0 0.0.0.0 Serial0/0/0 210 permanent ip route 0.0.0.0 0.0.0.0 Cellular0/1/0 220 permanent ip route 172.31.2.0 255.255.255.0 Cellular0/1/0 permanent ip route 192.168.3.0 255.255.255.0 10.1.1.1 permanent ip route 192.168.3.0 255.255.255.0 Cellular0/1/0 210 permanent ! access-list 1 permit any dialer-list 1 protocol ip list 1 ! control-plane ! line con 0 logging synchronous login local line aux 0 line 2 no activation-character no exec transport preferred none transport input all transport output pad telnet rlogin lapb-ta mop udptn v120 ssh stopbits 1 line 0/1/0 exec-timeout 0 0 script dialer gsm login modem InOut no exec transport input all rxspeed 7200000 txspeed 5760000 line 0/1/1 no exec rxspeed 7200000 txspeed 5760000 line vty 0 4 access-class 23 in privilege level 15 password 7 censored login local transport input all line vty 5 15 access-class 23 in privilege level 15 password 7 censored login local transport input all line vty 16 1370 password 7 censored login transport input all ! scheduler allocate 20000 1000 end 远程站点B的清理运行configuration：
version 15.1 service tcp-keepalives-in service tcp-keepalives-out service timestamps debug datetime msec service timestamps log datetime msec service password-encryption service udp-small-servers service tcp-small-servers ! hostname remoteB ! boot-start-marker boot-end-marker ! logging buffered 51200 warnings enable secret 5 censored ! no aaa new-model clock timezone wst 8 0 ! no ipv6 cef ip source-route ip cef ! no ip domain lookup ip domain name yourdomain.com multilink bundle-name authenticated ! chat-script gsm "" "ATDT*98*1#" TIMEOUT 30 "CONNECT" username admin privilege 15 secret 5 censored ! controller Cellular 0/1 ! interface Embedded-Service-Engine0/0 no ip address shutdown ! interface GigabitEthernet0/0 ip address 192.168.3.1 255.255.255.0 duplex auto speed auto ! interface GigabitEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/0/0 ip address 10.1.1.1 255.255.255.252 encapsulation frame-relay clock rate 2000000 cdp enable frame-relay interface-dlci 16 frame-relay lmi-type ansi frame-relay intf-type dce ! interface Cellular0/1/0 ip address negotiated encapsulation ppp dialer in-band dialer idle-timeout 2147483 dialer string gsm dialer-group 1 async mode interactive ppp chap hostname censored ppp chap password 7 censored ppp ipcp dns request cdp enable ! interface Cellular0/1/1 no ip address encapsulation ppp ! interface Dialer0 no ip address ! ip forward-protocol nd ! no ip http server no ip http secure-server ! ip route 0.0.0.0 0.0.0.0 Serial0/0/0 210 permanent ip route 0.0.0.0 0.0.0.0 Cellular0/1/0 220 permanent ip route 172.31.2.0 255.255.255.0 Cellular0/1/0 permanent ip route 192.168.2.0 255.255.255.0 10.1.1.2 permanent ip route 192.168.2.0 255.255.255.0 Cellular0/1/0 210 permanent ! kron occurrence PING in 1 recurring policy-list ICMP ! access-list 1 permit any dialer-list 1 protocol ip list 1 ! control-plane ! line con 0 logging synchronous login local line aux 0 line 2 no activation-character no exec transport preferred none transport input all transport output pad telnet rlogin lapb-ta mop udptn v120 ssh stopbits 1 line 0/1/0 exec-timeout 0 0 script dialer gsm login modem InOut no exec transport input all rxspeed 7200000 txspeed 5760000 line 0/1/1 no exec rxspeed 7200000 txspeed 5760000 line vty 0 4 access-class 23 in privilege level 15 password 7 censored login transport input all line vty 5 15 access-class 23 in privilege level 15 password 7 censored login transport input all line vty 16 1370 password 7 censored login transport input all ! scheduler allocate 20000 1000 end
我遇到的最后一个问题是3G接口在闲置几分钟后就会closures。 我试过每分钟都用kron来ping本地的HWIC-3G-HSPA接口（蜂窝0/1/0），但是没有成功。 手动ping IP（由电信公司）到ce0 / 1/0的IP确实会使接口向上。
有任何想法吗？
谢谢
你可以设置一个伪造的GRE隧道来发送数据包来维护接口。
router(config)# int tun0 router(config-if)# ip unnunbered <lan interface> router(config-if)# tunnel mode gre router(config-if)# tunnel source <lan interface> router(config-if)# tunnel dest <default 3G gateway>
隧道目的地也可以是任何IP，至less你有一个通过3G的路线。 隧道将停留（因为保持消息不会被回答），但发送的保持活动将迫使3G接口保持。