TCPWINDOWSIZE

The TCPWINDOWSIZE option specifies, in kilobytes, the amount of receive data that can be buffered at one time on a TCP/IP connection. The sending host cannot send more data until it receives an acknowledgment and a TCP receive window update. Each TCP packet contains the advertised TCP receive window on the connection. A larger window lets the sender continue sending data, and may improve communication performance, especially on fast networks with high latency.

Note:
  • To improve backup performance, increase the TCPWINDOWSIZE on the server. To improve restore performance, increase the TCPWINDOWSIZE on the client.
  • The TCP window acts as a buffer on the network.
  • A window size larger than the buffer space on the network adapter might degrade throughput due to resending packets that were lost on the adapter.
  • Linux operating systemsAIX operating systemsThe TCPWINDOWSIZE option is not related to the TCPBUFFSIZE option nor to the send and receive buffers allocated in client or server memory.

Syntax

Read syntax diagramSkip visual syntax diagramTCPWindowsizekilobytes

Parameters

kilobytes

Specifies the size you want to use, in kilobytes, for the TCP/IP sliding window for your client node. You can specify a value from 0 to 2048. The default is 63. If you specify 0, the server uses the default window size set by the operating system. Values from 1 to 2048 indicate that the window size is in the range of 1 KB to 2 MB.

Examples

tcpwindowsize 63