Host-routes let you add entries into the OSBC routing table, the next image shows the routing table in the Oracle SBC lab environment (IPv6 routes are ignored):

When sending traffic to a network not explicitly defined the default gateway is used, in this case using interface wancom0.

Let’s create an hypothetical scenario where a new network 172.16.0.0/24 needs to be reached using s0p1, as shown in the next image:

If we try to reach that network, as it is not defined in a host route OSBC will try to use the default gateway, this can be verified sending ICMP packets as shown below (see how packets are generated from wancom0 interface!):

Now let’s define a new host route entry, and lets see how it modifies the routing table and the ICMP messages:

After applying the changes, this is the new routing table:

and now the final test (its normal that host doesnt reply but you can confirm that now its using s1p1 interface):