IP SLA Tracking of multiple interfaces with static route

[philnewton007]

Hi,

I have a Cisco IR829 with cellular, Wireless and LAN interfaces. I want to use the cellular interface as the Primary and if that fails then use the Wireless interface which is connected to the customers network, as a last resort the local LAN. Only fail to the LAN if both the Cellular and Wireless interfaces fail to reach the internet. Can I use IP SLA to track multiple interfaces?

See config below:

!
ip route 0.0.0.0 0.0.0.0 Cellular0 track 1
ip route 0.0.0.0 0.0.0.0 wlan-ap0 track 2
ip route 0.0.0.0 0.0.0.0 GigabitEthernet0 dhcp 20
!
!
ip sla 1
icmp-echo 8.8.4.4 source-interface Cellular0
timeout 1000
threshold 2
frequency 5
!
ip sla 2
icmp-echo 8.8.4.4 source-interface wlan-ap0
timeout 1000
threshold 2
frequency 5
!
ip sla schedule 1 life forever start-time now
!
track 1 ip sla 1 reachability
track 2 ip sla 2 reachability
!
track 3 list boolean and
object 1
object 2
!

Does the above config look right?

Thanks,

Phil

[Seb Rupik]

Hi there,

You will want to add an metric value to the track 2 static route otherwise it will be installed alongside the primary static route. 

!
ip route 0.0.0.0 0.0.0.0 wlan-ap0 2 track 2
ip route 0.0.0.0 0.0.0.0 GigabitEthernet0 dhcp 3
!

Also keep the metric of the last static route below  the default AD for EIGRP summary routes (5).

cheers,

Seb.

[philnewton007]

Thanks Seb. What should be the expected outcome of this config be? I'm just trying to get my head round it.

[Georg Pauwen]

The idea is to have a sequential failover. If the primary route fails, the secondary takes over. If BOTH routes fail, the tertiary will take over.

You might want to check if this works as designed before deploying.

[Seb Rupik]

As @Georg Pauwen points out, configuring static routes with incrementing metrics which themselves have tracks states of true will ensure that only one route will be installed at a time.

cheers,

Seb.

[Georg Pauwen]

Hello,

you might want to put the below EEM script into your config as well, which clears the current, active NAT translations in case of a failover, so you don't have to wait for the NAT entries to time out:

event manager applet CLEAR_NAT

event track 3 state any

action 1.0 cli command "enable"

action 2.0 cli command "clear ip nat translation *"

[philnewton007]

Thanks Georg, I have this is the config, but had been event tracking the wrong interface.