Auto-Failover between 2 ISPs

[balbeer.singh84]

Hi,

I have 2 ISPs & configured my interfaces as below :

WAN INTERFACE 1 :-

interface GigabitEthernet0/1

description TCL_WAN

ip address 116.212.176.2 255.255.255.224

ip nat outside

ip virtual-reassembly in

ip policy route-map TCL

duplex full

speed 100

crypto map clientmap

WAN INTERFACE 2 :-

interface GigabitEthernet0/2

description BHARTI_WAN

ip address 61.95.191.54 255.255.255.252

ip nat outside

ip virtual-reassembly in

ip policy route-map BHARTI

duplex full

speed 100

LAN INTERFACE :-

interface GigabitEthernet0/0

description LAN_INTERFACE

ip address 192.168.32.1 255.255.255.224

ip nat inside

ip virtual-reassembly in

duplex full

speed 100

The Auto-Failover configuration is :-

ip sla 1

icmp-echo 203.124.230.12 source-ip 116.212.176.2

frequency 5

ip sla schedule 1 life forever start-time now

track 1 ip sla 1 reachability

delay down 5 up 30

!

track 2 interface GigabitEthernet0/2 ip routing

delay down 5 up 5

Default IP Routes are :-

ip route 0.0.0.0 0.0.0.0 116.212.176.1 track 1          //Primary WAN

ip route 0.0.0.0 0.0.0.0 61.95.191.53 250 track 2     //Backup WAN

Please tell me whether TRACK 2 is also really needed for my requirement OR only Track 1 will be helpful. What will be the impact of Track 2? Please suggest.

-Balbeer Singh.

[cadet alain · Accepted solution]

Hi,

only track 1 is needed but you should modify the IP SLA like this:

no ip sla 1

ip sla 1

icmp-echo 203.124.230.12 source-interface GigabitEthernet0/0

frequency 5

I have a question though, why are you doing PBR on inbound WAN traffic ? Shouldn't it be on the LAN interface instead ?

Regards.

Alain

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[balbeer.singh84]

Hi Alain,

Thanks for the reply. Please tell me what can be the impact of Track 2 ?

I faced one problem in which both the WAN 1 was down which made Track 1 down but when WAN 1 came up, the Track 1 in the router was not up. So, I had to add the another default route entry manually as ip route 0.0.0.0 0.0.0.0 116.212.176.1. After that the Track 1 came up. Why this was happened? Please suggest. After adding this route, the entries in the router were :

ip route 0.0.0.0 0.0.0.0 116.212.176.1 track 1

ip route 0.0.0.0 0.0.0.0 61.95.191.53 250 track 2

ip route 0.0.0.0 0.0.0.0 116.212.176.1

Please Suggest.

-Balbeer Singh.

[cadet alain]

Hi,

My suggestion is to use the source-interface in the IP SLA object and if it is still failing then you can either:

- put a host route for the destination that IP SLA is pinging with a next-hop on the primary interface

-configure local PBR for ICMP traffic destined to the host IP SLA is pinging

Regards.

Alain

Don't forget to rate helpful posts.