I have a HTTP-based RESTful web service where some of the resources are representations of the states of physical entities such as a router or radio base station. At times, one or more of these physical entities may be unavailable. When a client makes a request related on a entity which is unavailable, I want the web service to reply back in a way which would cause the client to try again later.
I plan on having the server send a 503 (Service Unavailable) response with a Retry-After header indicating the length of time to wait for trying again.
I am wondering if anyone else has had to find a solution for this, and what approach was taken.