Journal: Pull or Push from 1000 devices in the network

"I'm designing a system where 1000 devices have to interact with my server periodically and on demand. A requirement is that devices are spread geographically. My manager would like to push data from devices to server. But a lot of them are behind firewalls, so a socket-based solution won't always work. I personally feel that if server polls the devices every 2 mins (a req) using HTTP, that's 1000 requests spread over 2 mins. Does anyone know a which way is a better choice? Then there is an issue of traps generated by devices which have to be handled. In either case which is the best way to achieve this.