Cisco – Multiple WANs/Out-of-band (Cisco 1900)

ciscocisco-iosfailoveroobwan

I've got a Cisco 1900 router which connects to the Internet using a primary and a secondary WAN connection.
When the primary connection is up, all traffic use this link. When the primary connection is down, I use the secondary connection to connect to the router to troubleshoot why the primary link is down.

Sometimes I would also like the two connection to be up and running at the same time. I would then like to be able to access the router using SSH on either one of its public IP-addresses.

Is there any (easy) way of having both these interfaces accessible at the same time?

Best Answer

As long as both interfaces have public IP addresses, which it sounds like, you have two options:

1) IP SLA: outbound traffic will only use one interface at a time.

Essentially, you configure a static default route out the primary interface, which is tracked and a static default route out the secondary interface. If the tracking finds an issue, the tracked route is removed, making the default route out the secondary interface

IP SLA link

R1(config)# ip sla 1
R1(config)# icmp-echo $primaryNextHop source-interface $primaryInterface
R1(config)# timeout 1000
R1(config)# threshold 2
R1(config)# frequency 3
R1(config)# ip sla schedule 1 life forever start-time now
R1(config)# track 1 ip sla 1 reachability
R1(config)# ip route 0.0.0.0 0.0.0.0 $primaryNextHop track 1
R1(config)# ip route 0.0.0.0 0.0.0.0 $secondaryNextHop 10

2) BGP peer with ISPs: this can be configured to allow traffic outbound on both interfaces at the same time. You can also set this up to allow ISP1 to receive traffic for the secondary interface and vice versa (BGP Multihoming)

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