site_archiver@lists.apple.com Delivered-To: Macnetworkprog@lists.apple.com Chris, On Sep 30, 2005, at 7:51 AM, Chris McFarling wrote: /etc/sysctl-macosxserver.conf states the following: Vincent _______________________________________________ Do not post admin requests to the list. They will be ignored. Macnetworkprog mailing list (Macnetworkprog@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/macnetworkprog/site_archiver%40lists.... # Some sysctl variables administrators may consider setting in /etc/sysctl.conf: # # This sets a threshold that triggers increasing the send/recv windows for TCP # connection from 32K to 64K to improve some file downloads. # If your server has a lot of memory and serves only local traffic (like AFP cli ents # on local LAN) you may want to increase this value beyond its default of 256 pc bs. # # net.inet.tcp.sockthreshold=512 When it says"256 pcbs", what does that mean? That's the number of TCP control blocks, which is approximately the number of active TCP connections. Also, how does the triggering mechanism work...when does the OS use 32K windows and when does it use 64K windows? The OS uses 64 K windows as long as the number of TCP connections is less than net.inet.tcp.sockthreshold. When the number of TCP connections is greater net.inet.tcp.sockthreshold the stack will use the values of net.inet.tcp.recvspace and net.inet.tcp.sendspace The reason I ask is because I actually want to set the window size to 18K. I'm doing some testing and want to see if a smaller window size will increase performance on my network. In doing so I'm trying to understand OS X's behavior though. To disable this mechanism and force the stack to always use a 18K you simply need to set net.inet.tcp.sockthreshold to zero This email sent to site_archiver@lists.apple.com