Here it is a little challenge. You will find two CPE connected to two different PE. The two CPE are used in “fail-over” model by using HSRP. The two CPE dial on PE. CPEprimaire dials through a Bridge, CPESecondaire dials directly.

CPEPrimaire :
-------------
on LAN fastethernet:
standby 5 ip 10.0.0.1
standby 5 preempt
standby 5 track Dialer 1
standby 5 priority 105

CPESecondaire :
---------------
on LAN fastethernet :
standby 5 ip 10.0.0.1
standby 5 preempt

 

Do you think when link between PE75 and Bridge will be DOWN, HSRP will act as waited : PCs on LAN will have for gateway CPESecondaire ? You can shut interface WAN on bridge to try it. I enclosed GNS3 lab : hsrp-challenge.