Can someone explain the difference between GCM and Google Pub/Sub

Question

Google did answer the question here

https://cloud.google.com/pubsub/faq

But I\'m still unclear on which scenarios would each be used for?

Is there

Answer 1

Google Pub/Sub is a Enterprise services bus, you could use it when your business has many systems, but these systems are separated, with their our databases, with a enterprise service bus you could communicate these systems by messages. And GCM( now Firebase Cloud Messaging(FCM)) is a notification server, when you can communicate or send a information from a device to other devices, you could use FCM.