Configuration Example - Cisco CISCO851-K9 - 851 Integrated Services Router Configuration Manual

Dial Backup Feature Limitations
Table 13-1 Dial Backup Feature Support and Limitations Summary (continued)
WAN Encapsulation Dial Backup
Type Possible?
Cisco 876, 877, or 878
PPP over ATM Yes
PPP over Ethernet
RFC 1483 (AAL5, Yes
SNAP, and MUX)

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
Cisco 850 Series and Cisco 870 Series Access Routers Software Configuration Guide
13-6
Dial Backup Method Limitations
Backup interfaces Floating static route and dialer watch need a routing protocol
to run in the router. The dialer watch method brings up the
Floating static routes
backup interface as soon as the primary link goes down. The
Dialer watch
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.
Backup interfaces If bridging is done through the WAN interface, it is not
supported across the auxiliary port.
Floating static routes
Dialer watch
Chapter 13 Configuring Dial Backup and Remote Management
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