If Agent services is down how we will get alert/notification

Any one please reply for my doubt.

we have more than 200 servers in our environments, All the database stuffs working through Agent services only like Backup jobs,profile jobs,trace jobs,maintenance jobs, those jobs are success/failures, we are getting alert through database mail to our outlook, 

Here is my doubt : If any one of the server related to agent services is down(example 179 server is down) how we know that and here what we need to do to find exact server related agent services  is down.

Thanks

Ramu Annamalai | DBA |