The limits on the number of backends that can be registered:

• The Controller enforces a limit of 1000 backend registrations in the business application for each type of backend (that is, 1000 HTTP backends, 1000 JMS backends, and so on). This setting is controlled by the backend.registration.limit Controller Setting. This limit applies whether the backends are resolved to a tier or unresolved.
• Agents apply a limit of 300 unresolved backends per application, regardless of the type. When determining if the limit has been reached, it's important to include all types. For example, agents, databases, remote services, etc., should all be included when totaling unregistered backends if it appear that the limit has not been reached but the logs have reported it has. To safeguard against reaching the limit, we recommend that you delete unnecessary backends.

When the backend count exceeds the limit, the "All Other Traffic" category is automatically created. The logs indicate that a limit has been reached by a log entry such as the following:

[pool-1-thread-2] 21 Mar 2013 11:28:01,702 DEBUG AFastBackendResolver - Not discovering backend call [Exit Point Type [WEB_SERVICE] Properties [{SERVICE_NAME=ZipCodeService002.wsdl}] Display Name [ZipCodeService002.wsdl]] because maximum limit of discovered backends [300] reached.