Introduction

ActiveMQ MPX improves the performance of the clients and extends the scalability of server configurations. When the term client is used in this guide, it refers to any client that can take advantage of one or more ActiveMQ MPX features.

Changes to the server configuration’s repository are broadcast in an encrypted format to StarTeam clients and MPX Cache Agents through a publish/subscribe channel. The MPX Event Transmitter broadcasts encrypted messages about changes to objects, such as change requests, and the MPX File Transmitter broadcasts archive files.

Caching modules automatically capture events that a client subscribes to. This reduces the client’s need to send refresh requests to the server and improves client response times for the user.

You can install and configure MPX Cache Agents to cache files and/or objects in a network-near location to speed up check-out operations. They reduce the distance that the data travels at the time of the client check-out operation. While MPX Cache Agents are MPX clients that rely on messages and files transmitted by the File Transmitter, they also serve other MPX clients as they check out files.

The ActiveMQ MPX technology offers a number of key benefits, including:

Bandwidth multiplication	Every request by a client that is fulfilled from a cache is a request that the server does not have to fulfill. As a result, a single server configuration can support more clients. In certain environments, requests for item refresh may constitute up to 50% of client-to-server traffic. Refresh requests increase with project size and when the “All Descendants” option is used. For the person who builds software products, check-out operations are a very high percentage of the client-to-server traffic. Using the Bulk CheckOut (bco) command-line utility with a MPX Cache Agent can speed up the time it takes to create a build.
Performance acceleration	Because the event caching modules reside on the same computer as the client and the MPX Cache Agents are on computers that are network-near the supported clients, requests filled from the caches are faster than those requiring a round-trip to the server.
Burst control	As the number of clients increases, the likelihood of burst periods increases, during which time a server configuration can become deluged and less responsive. The caching modules even-out the demand on a server configuration.

The following lists the MPX features of which specific clients can take advantage.

• StarTeam Cross-Platform Client: Event and file/object caching.

• Bulk CheckOut (bco) command-line utility: File caching.

• IDEs based on StarTeam Cross-Platform Client and .NET components (such as the Eclipse integration and the Visual Studio .NET integration) - Event and file/object caching.