Optimizing Connectivity (SQL Server)

To optimize performance, you can modify the settings based on the bandwidth of the network connection. The following table shows the bandwidths used by some of the TCP/IP networks supported by SQL Server Compact 3.5.

Bandwidth range	Network type
High	Ethernets or local area networks (LAN) USB connections using ActiveSync (device-only)
Medium	Wireless LAN networks
Low	Cellular or mobile networks

When data is synchronized over a cellular or mobile network, requests sent to the server—and responses from the server—can time out. This occurs when a low-bandwidth connection requires too much time to transmit the data. Because time-outs will cause synchronization to fail, specify a longer time-out value.

However, if time-outs are not a problem, set shorter time-out values because a delay in response from the server over a high-bandwidth connection is more likely caused by an unresponsive server. Therefore, applications that run on the desktop and connect to the server over a LAN and devices that connect to the server by using an ActiveSync connection should use shorter time-out values.

Applications that connect to the server over various types of networks should detect the network bandwidth and set appropriate time-out values.

Synchronization Time-Out Properties

The following time-out properties of the merge replication and RDA programming objects can be set to optimize synchronization over various network bandwidths.

ConnectionRetryTimeout: Specifies the time, in seconds, to continue to retry sending requests after an established connection has failed.

ConnectTimeout: Specifies the time, in milliseconds, to wait for a connection to the server.

ReceiveTimeout: Specifies the time, in milliseconds, to wait for the response to a server request.

SendTimeout: Specifies the time, in milliseconds, to wait to send a request to the server.

Time-out Optimization

The following table provides recommendations for setting the time-out values, depending on the network bandwidth.

Property	High-bandwidth	Medium-bandwidth	Low-bandwidth	Default
ConnectionRetryTimeout (s)	30	60	120	120
ConnectTimeout (ms)	3000	6000	12000	None
ReceiveTimeout (ms)	1000	3000	6000	60000
SendTimeout (ms)	1000	3000	6000	None