Cisco CISCO876-SEC-I-K9 Configuration Guide - Page 124

Dial Backup Feature Limitations Chapter 13 Configuring Dial Backup and Remote Management Table 13-1 Dial Backup Feature Support and Limitations Summary (continued) WAN Encapsulation Dial Backup Type Possible? Dial Backup Method Cisco 876, 877, or 878 PPP over ATM Yes Backup interfaces PPP over Ethernet Floating static routes Dialer watch RFC 1483 (AAL5, Yes SNAP, and MUX) Backup interfaces Floating static routes Dialer watch Limitations Floating static route and dialer watch need a routing protocol to run in the router. The dialer watch method brings up the backup interface as soon as the primary link goes down. The backup interface is brought down as soon as the dialer timeout is reached and the primary interface is up. The router checks the primary interface only when the dialer timeout expires. The backup interface remains up until the dialer timeout is reached, even though the primary interface is up. For the dialer watch method, a routing protocol does not need to be running in the router, if the IP address of the peer is known. If bridging is done through the WAN interface, it is not supported across the auxiliary port. Configuration Example The following three examples show sample configurations for the three dial backup methods. Example 13-1 Configuring Dial Backup Using Backup Interfaces ! vpdn enable ! vpdn-group 1 accept-dialin protocol pppoe ! ! Specifies the ISDN switch type isdn switch-type basic-net3 ! interface vlan 1 ip address 192.168.1.1 255.255.255.0 hold-queue 100 out ! ! ISDN interface to be used as a backup interface interface BRI0 no ip address encapsulation ppp dialer pool-member 1 isdn switch-type basic-net3 ! interface ATM0 backup interface BRI0 no ip address no atm ilmi-keepalive pvc 1/40 encapsulation aal5snap pppoe-client dial-pool-number 2 13-6 Cisco 850 Series and Cisco 870 Series Access Routers Software Configuration Guide OL-5332-01