Many network vendors are publishing simulators to the community. A simulator can be a way to complete a training or can be used for a PoC .
GNS3 maybe is the most famous emulator while others like eNSP for Huawei, Cisco’s VIRL , Juniper Junosphere are available or will be available soon.
The big name missing so far was HP. Last December HP announced on Linkedin the availability of a simulator for Comware platform: