Backup Interface.

[dmitrinik]

Hello everyone,

I am trying to backup main Internet connection via Cablevision with Sprint 3G.

When there is a problem on Cablevision side, cable modem is unable to route any IP traffic from office network. When it happens, I want to route IP traffic via Sprint 3G.

Cisco 2811:

FastEthernet0/0 is Cablevision outside interface with static IP.

FastEthernet0/1 is LAN inside interface.

Cellular 0/3/0 is Sprint outside interface.

Thank you very much.

[Mohamed Sobair]

Hello,

This can be accomplished with Normal Static default routes with (IP Sla). if you do tracking for the default routes, then each one will be backup for the other.

Regards,

Mohamed

[dmitrinik]

Mohamed,

Can you please provide configuration example?

I am not familiar with (IP Sla).

That would really help.

Thank you.

[Mohamed Sobair · Accepted solution]

below is a configuration example:

track 1 rtr 1 reachability

ip sla 1

icmp-eho 4.2.2.2 source-interface f0/1

frequency 10

ip sla shedule 1 life forever start time now

ip route 0.0.0.0  0.0.0.0 f0/0 track1

ip route 0.0.0.0 0.0.0.0 cellular 0/3/0 200

with the above, always f0/0 will be your primary outgoing link and once tracking failed, it will switch to the backup Cellular interface.

However, if the primary link came backup online, it will then switched to the primary link.

Regards,

Mohamed

[dmitrinik]

Thank you very much.