
Implementation Notes
3-19
Figure 3-6. Dialing an Alternate Router Using IP Unnumbered Interfaces
If the primary connection between Routers A and B goes down, the backup circuit
takes over, adopting the configuration of the primary circuit. The backup circuit
tries to call Router B, but it finds it cannot establish a connection.
Because you configure unnumbered IP addresses on the primary circuit, Router A
is not limited to calling Router B. Router A dials the next phone number in its
outgoing phone list, which is Router C’s phone number, and establishes a
connection.
For Router A to dial Router C, you must configure the routers according to the
requirements in Table 3-1.
Table 3-1. Configuration for Routers A and C
Router A Router C
Configure an unnumbered primary
circuit.
Configure a demand pool with unnumbered
demand circuits.
Configure routing protocols for the
primary circuit.
Configure routing protocols on the demand
circuit to match Router A’s routing protocol
configuration for the primary circuit.
N/A Set Connection Mode parameter to No Dial.
Include CHAP Name/Secret or
PAP ID/Password for the primary circuit.
Configure the Caller Resolution Table to
include Router A’s CHAP Name/Secret or
PAP ID/Password.
0.0.0.0 192.32.10.2
Router B
Regional
0.0.0.0 192.32.10.1
0.0.0.0
0.0.0.0
Backup
Primary
3
12
Leased
Line 1 – Primary line between Routers A and B
Line 2 – Leased line between Routers B and C
Line 3 – Backup line for Router A
Demand line for Router C
Demand
Router C
Central
Router A
Remote
Comentarios a estos manuales