018- IP SLA based Tracking for HSRP

Device detail:

R3 = Primary ISP R4 = Secondary ISP
R1 = Primary WAN router R2 = Secondary WAN router
R5 = Host

• R3 and R4 advertises subnet 200.200.200.200/32 and 100.100.0.0/16 (summary for 100.100.10.1, 100.100.20.1, 100.100.30.1) to R1 and R2 respectively.
• AS path prepanding is configured on R2 for advertised route from R4, so that R3 is preferred over R4 for all outgoing traffic.

Objective:
Configure PBR on R1 so that traffic destined to only 100.100.20.1 subnet is sent to R4 via R2 only if R4 is reachable.


Configuration on R1
!
ip route 20.20.20.2 255.255.255.255 192.168.1.3
!
ip sla 1
icmp-echo 20.20.20.2 << ip address of R4 (backup isp)
threshold 200
frequency 5
!
ip sla schedule 1 life forever start-time now
!
track 3 rtr 1 << track 3 mapped to ipsla 1
!
route-map test permit 10
match ip address 101
set ip next-hop verify-availability 192.168.1.3 1 track 3 << conditional set command


Configuration on R2
!
ip route 100.100.20.0 255.255.255.0 20.20.20.2