Testing Connectivity

I currently have two internet sources. The secondary internet source is just used for fail over and nothing else. What i would like to do is test that periodically to make sure the internet on that port is working. It has its own interface that is called sbcdsl. I need to send a ping through that specific internet and make sure i get a reply a lot like netwatch. The problem is netwatch doesn’t allow for a certain interface. Any suggestions on how to accomplish this?

Also if it is helpful i was given /29 for the dsl.

‘src-address’ might be specified for the ‘ping’ command, where you can specify address of the router that belongs to the secondary interface.
As well ‘ip route’ command has option ‘check-gateway’, where you can specify ‘ping’, router will send ‘pings’ to the respective gateway, route will be disabled, if gateway will not answer.