- Fixed routing scheme: The channel has predefined input terminals wired to predefined processing elements, and predefined output terminals wired to predefined processing elements. Every event that is received on any input terminals is sent to all output terminals. Note that this type of channels can be defined implicitly.
- Subscription-based: EPAs or consumers can subscribe to the channel dynamically. The routing decision is determined according to the list of subscribers that is valid at the time that a decision is made.
- Itinerary-based: The sink's input terminal identifier or identifiers are obtained from some attribute in the event's payload, this is used to send an event to a specific consumer instance, when the EPN node is the consumer class.
- Context-based: The channel makes routing decisions based on the context to which the EPA belongs. This is applicable for pattern detection ("complex event processing") type of EPA. The channel selects the appropriate run-time EPA based on the context defined in the pattern- I'll discuss contexts in length in one of the next postings, as this is the topic of the next chapter in the book.
- Type-based: The channel makes routing decisions based on the event type of the event that is being routed.
- Content-based: The routing decision is based on the event's content, this can be phrased as assertions, rules, decision trees or decision tables, and are based on the input event content, as well as context information.
This is just the basic definition, in one of the next postings I'll show example of how all these concepts fit together.