In all the Service Bus examples and tutorials I've seen, they cover publishing a single message to a single Topic that is picked up by a single listening Subscriber. Whilst this is good for a simple practical overview, it doesn't really explain how Topics should be used in the real world.
I have a large ecommerce application that spans many subdomains, such as Order, Customer and Product management to name a few, and will be using an ESB to communicate events between these disparate systems. I will be using Pub-Sub via Topics.
Initially I was just using a single Topic per each different message type I was sending, however I could see that this was just going to get unmanageable as the system would just have too many types of messages to send to justify a 1-to-1 Message Type to Topic. e.g.
Then I thought that I could use a Topic per aggregate in the system. However because of the multiple bounded contexts in the domain, an aggregate in one system could be different to an aggregate, with the same name, in another system. So this implementation might be quite confusing.
So having a Topic per ubiquitous model seems like a better solution, and this can be based off the Canonical Data Model that is used to transform messages across the service bus. Is this a common approach ? Or is dividing the Topics up per functional concern a better method ?
I can see that there are going to be compromises to whichever implementation I pick, so I'm looking for good tips, historic examples of success and pitfalls to avoid.