ramandeep-singh-1983 · November 15, 2019 08:02
diff --git a/azure-iot-messaging-service-comparison.csv b/azure-iot-messaging-service-comparison.csv
Criteria	Event Grid	IoT Hub Message Routing	Event Hub	Service Bus Topics
Event delivery mechanism (Push/Pull)	Push	Push	Pull	Pull
Supported sources	Life-cycle events	Life-cycle events	Life-cycle events	Life-cycle events
	Telemetry	Telemetry	Telemetry	Telemetry
		Device twin change events	Device twin change events	Device twin change events
		Digital twin change events	Digital twin change events	Digital twin change events
Supported targets	Webhooks	Event hubs	Acts as an event sink and requires consumers to pull data from it. SDKs in various languages are provided for the same.	Acts as a queue and requires consumers to pull data from it. SDKs in various languages are provided for the same.
	Storage queues	Service bus queues
	Event hubs	Service bus topics
	Hybrid connections (Enterprise WebSocket)	Storage containers
	Service bus queues
Reliability	24-hour retry with exponential back-off to make sure events are delivered.	High: Delivers each message to the endpoint at least once for each route. Expires all messages that are not delivered within one hour.	At least once delivery at scale.	Reliable asynchronous message delivery that requires polling.
	Delivers each message to the WebHook at least once for each subscription. Expires all events that are not delivered within 24 hours.			At least once delivery.
Scalability	Serverless and dynamically scalable.	High scalability	High scalability.	Scalable but quotas are defined here
				Performance improvement information is here
Ordering of events	Not guaranteed.	Ordering of events is maintained.	Ordering of events is maintained.	Optional in-order delivery.
Use cases	Suitable for discrete events	Suitable for streaming data as well as discrete events.	Suitable for streaming data.	Suitable for enterprise messaging, transactional data.
	Best suited for processing independent events in parallel.		Suitable for reading events but requires polling.
Other features/caveats	3rd party services can register webhooks and event grid will deliver the events to registered webhooks. No polling is required in this case.	IoT Hub message routing is a message broker and doesn't act as a final destination for reading events or messages.	Event Hub is a highly scalable message broker and event sink from where consumers can pull out the relevant data.	Advanced messaging features like FIFO, batching/sessions, transactions, dead-lettering, temporal control, routing and filtering, and duplicate detection.
	Event Grid is significantly more scalable than Service Bus, supporting up to 10,000,000 events per second in a single Azure region. To achieve this, Event Grid might deliver events out of order, while Service Bus guarantees in-order message delivery.	The purpose of message routing is to forward the event/message to appropriate handler based on the defined routing rules or queries.	Event Hub works well for events as well as messages.	Service Bus topics work with messages, not events. They let receivers decide when to read a message, and they require the receiver to actively poll for new messages.
	The Event Grid will wait for, at most, 60 seconds for an event to be positively acknowledged. If there’s any chance that the processing will take longer, it’s better to turn to the Service Bus pull model that allows for processing to take much longer while maintaining a lock on the message.		Event Hub can manage high throughput of incoming events and consumers don't need to build complex logic to handle high throughput of incoming events. Consumers can pull the messages as per their convenience.	For long running processing tasks, it’s better to turn to the Service Bus pull model that allows for processing to take much longer while maintaining a lock on the message.
	Service Bus is fast, but Event Grid provides near real-time performance, with 99% of events delivered in less than a second.
	The WebHook consumer service has to be highly performant and horizontally scalable so that events/notifications are delivered in near real-time and that the delivery is not affected by high throughput of incoming events.
	Twin change events are not delivered by IoT hub messaging to Event Grid.