Microsoft KB Archive/203085

= Windows CE's TCP/IP stack enhancement on wireless network =

Article ID: 203085

Article Last Modified on 11/4/2005

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APPLIES TO


 * Microsoft Windows CE 3.0 for the Handheld PC Professional Edition
 * Microsoft Windows CE 2.12 for the Handheld PC
 * Microsoft Windows CE 2.11 for the Handheld PC
 * Microsoft Windows CE 2.1 for the Handheld PC
 * Microsoft Windows CE .NET 4.2

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This article was previously published under Q203085



SUMMARY
There are several registry settings that allow one to improve Windows CE's TCP/IP behavior on a wireless network.



MORE INFORMATION
To improve Transmission Control Protocol/Internet Protocol (TCP/IP) networking performance on a wireless network, the following TCP/IP parameters may need to be tuned to the characteristics of the supporting network. Typical wireless network has high-delay and low-bandwidth characteristics.

The registry parameters are maintained on a per-network-adapter basis rather than a system-global basis:

TcpWindowSize
Sets recv window size; must be less than GlobalMaxTcpWindowSize; available in Windows CE version 2.1.

TcpInitialRTT
Sets initial round trip time (RTT) in milliseconds; default is 3000 milliseconds; it previously was a global parameter and was not exposed.

TcpDelAckTicks
Delayed Ack timer in milliseconds; it previously was a global hard-coded parameter; defaults to 200 milliseconds TCP/IP.

Initial congestion window is set to twice the Max Segment Size (MSS).

Fast retransmissions are supported; it triggers on every third Ack; Point-to-Point Protocol (PPP) and serial line Internet protocol (SLIP) are supported.

Windows CE 2.1 adds the ability to request additional Dynamic Host Configuration Protocol (DHCP) options from the server; replies are stored in the registry.

