| //// |
| Licensed to the Apache Software Foundation (ASF) under one |
| or more contributor license agreements. See the NOTICE file |
| distributed with this work for additional information |
| regarding copyright ownership. The ASF licenses this file |
| to you under the Apache License, Version 2.0 (the |
| "License"); you may not use this file except in compliance |
| with the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, |
| software distributed under the License is distributed on an |
| "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| KIND, either express or implied. See the License for the |
| specific language governing permissions and limitations |
| under the License |
| //// |
| |
| // Module included in the following assemblies: |
| // |
| // important-terms-concepts.adoc |
| |
| [id='how-routers-route-messages-{context}'] |
| = How routers route messages |
| |
| In a router network, _routing_ is the process by which messages are delivered to their destinations. To accomplish this, {RouterName} offers two different routing mechanisms: |
| |
| Message routing:: |
| Message routing enables you to distribute messages in anycast and multicast patterns. These patterns can be used for both direct routing, in which the router distributes messages between clients without a message broker, and indirect routing, in which the router enables clients to exchange messages through a message broker. |
| + |
| Message routing is useful for the following types of requirements: |
| + |
| -- |
| * Default, basic message routing |
| + |
| {RouterName} automatically routes messages by default, so manual configuration is only required if you want routing behavior that is different than the default. |
| |
| * Message-based routing patterns |
| + |
| Message routing supports both anycast and multicast routing patterns. You can load-balance individual messages across multiple consumers, and multicast (or fan-out) messages to multiple subscribers. |
| |
| * Sharding messages across multiple message brokers when message delivery order is not important |
| + |
| Sharding messages from one producer might cause that producer’s messages to be received in a different order than the order in which they were sent. |
| -- |
| |
| Link routing:: |
| Link routing enables you to establish a dedicated, virtual "path" between a sender and receiver that travels through the router network. Link routes are typically used to connect clients to message brokers in scenarios in which a direct connection is unfeasible. Therefore, link routes enable messaging capabilities that are not possible with message routing, such as: |
| + |
| -- |
| * Transactional messaging |
| + |
| Link routing supports local transactions to a single broker. Distributed transactions are not supported. |
| |
| * Guaranteed message delivery order |
| + |
| Link routing to a sharded queue preserves the delivery order of the producer’s messages by causing all messages on that link to go to the same broker instance. |
| |
| * End-to-end flow control |
| + |
| Flow control is "real" in that credits flow across the link route from the receiver to the sender. |
| |
| * Server-side selectors |
| + |
| With a link route, consumers can provide server-side selectors for broker subscriptions. |
| -- |
| |
| .Additional resources |
| |
| * xref:configuring-message-routing-{context}[] |
| |
| * xref:creating-link-routes-{context}[] |
