---
title:  Durable Client Messaging
---

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You can configure the redundancy level for client queues that are stored on cache servers. This ensures that the client will not lose messages if it loses the connection to its primary server.

Durable messaging allows a disconnected client application to recover its subscribed data when it reconnects to the cache server because the server continues to queue messages for which the client has registered interest.

-   **[Durable Client Messaging Requirements](durable-client-messaging-req.html)**

    The messaging queues used for durable messaging are the same regular messaging queues used for basic server-to-client messaging, with additional requirements.

-   **[Client-Side Configuration](client-side-config.html)**

-   **[Sending Cache Ready Messages to the Server](sending-cache-ready-message.html)**

    After a durable client connects and initializes its cache, regions, cache listeners, and any interest registration, it invokes `readyForEvents` to indicate to the servers that the client is ready to receive any messages accumulated for it.

-   **[Disconnecting from the Server](disconnecting-from-server.html)**

    When a durable client closes its cache and disconnects, it tells the servers whether to maintain its queues.

-   **[Life Cycle of a Durable Client](durable-client-life-cycle.html)**

    This section discusses the high-level operation of a durable client through initial startup, disconnection, and reconnection.

-   **[Implementing Cache Listeners for Durable Clients](impl-cache-listeners-durable-clients.html)**

    A cache listener for durable clients requires all callback methods to behave properly when stored events are replayed. A cache listener has a callback method, `afterRegionLive`, specifically for durable clients aspects.