---
title:  Configuring Sockets in Multi-Site (WAN) Deployments
---

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When you determine buffer size settings, you try to strike a balance between communication needs and other processing.

This table lists the settings for gateway relationships and protocols, and tells where to set them.

<table>
<colgroup>
<col width="33%" />
<col width="33%" />
<col width="33%" />
</colgroup>
<thead>
<tr class="header">
<th>Protocol / Area Affected</th>
<th>Configuration Location</th>
<th>Property Name</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td><strong>TCP / IP</strong></td>
<td>---</td>
<td>---</td>
</tr>
<tr class="even">
<td>Gateway sender</td>
<td><code class="ph codeph">gfsh create gateway-sender</code> or
<p>cache.xml &lt;gateway-sender&gt;</p></td>
<td>socket-buffer-size</td>
</tr>
<tr class="odd">
<td>Gateway receiver</td>
<td><code class="ph codeph">gfsh create gateway-receiver</code> or cache.xml &lt;gateway-receiver&gt;</td>
<td>socket-buffer-size</td>
</tr>
</tbody>
</table>

**TCP/IP Buffer Sizes**

If possible, your TCP/IP buffer size settings should match across your installation. At a minimum, follow the guidelines listed here.

-   **Multisite (WAN)**. In a multi-site installation using gateways, if the link between sites is not tuned for optimum throughput, it could cause messages to back up in the cache queues. If a receiving queue overflows because of inadequate buffer sizes, it will become out of sync with the sender and the receiver will be unaware of the condition.

    The gateway sender's socket-buffer-size attribute should match the gateway receiver’s socket-buffer-size attribute for all gateway receivers that the sender connects to, as in these example `cache.xml` snippets:

    ``` pre
    Gateway Sender Socket Buffer Size cache.xml Configuration: 

    <gateway-sender id="sender2" parallel="true"
     remote-distributed-system-id="2"
     socket-buffer-size="42000"
     maximum-queue-memory="150"/>

    Gateway Receiver Socket Buffer Size cache.xml Configuration:
    <gateway-receiver start-port="1530" end-port="1551"
     socket-buffer-size="42000"/>  
    ```

**Note:**
WAN deployments increase the messaging demands on a <%=vars.product_name%> system. To avoid hangs related to WAN messaging, always set `conserve-sockets=false` for GemFire members that participate in a WAN deployment.

## <a id="socket_comm__section_4A7C60D4471A4339884AA5AAC97B4DAA" class="no-quick-link"></a>Multi-site (WAN) Socket Requirements

Each gateway sender and gateway receiver uses a socket to distribute events or to listen for incoming connections from remote sites.

<table>
<colgroup>
<col width="50%" />
<col width="50%" />
</colgroup>
<thead>
<tr class="header">
<th>Multi-site Socket Description</th>
<th>Number Used</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td><p>Listener for incoming connections</p></td>
<td><p>summation of the number of gateway-receivers defined for the member</p></td>
</tr>
<tr class="even">
<td><p>Incoming connection</p></td>
<td><p>summation of the total number of remote gateway senders configured to connect to the gateway receiver</p></td>
</tr>
<tr class="odd">
<td><p>Outgoing connection</p></td>
<td><p>summation of the number of gateway senders defined for the member</p></td>
</tr>
</tbody>
</table>

Servers are peers in their own distributed systems and have the additional socket requirements as noted in the Peer-to-Peer section above.

## <a id="socket_comm__section_66D11C8E84F941B58800EDB52194B087" class="no-quick-link"></a>Member produces SocketTimeoutException

A client, server, gateway sender, or gateway receiver produces a `SocketTimeoutException` when it stops waiting for a response from the other side of the connection and closes the socket. This exception typically happens on the handshake or when establishing a callback connection.

Response:

Increase the default socket timeout setting for the member. This timeout is set separately for the client Pool and for the gateway sender and gateway receiver, either in the `cache.xml` file or through the API. For a client/server configuration, adjust the "read-timeout" value as described in [&lt;pool&gt;](../../reference/topics/client-cache.html#cc-pool) or use the `org.apache.geode.cache.client.PoolFactory.setReadTimeout` method. For a gateway sender or gateway receiver, see [WAN Configuration](../../reference/topics/elements_ref.html#topic_7B1CABCAD056499AA57AF3CFDBF8ABE3).
