Thanks MBS... I was going to try the "restricted" setting to see if that impacts anything leaving the other values enabled/on. Since these are VMs, the other stuff I read is saying that the offloading settings may not really have any effect on the outcomes.
Don K ________________________________ From: Michael B. Smith <mich...@smithcons.com> To: NT System Admin Issues <ntsysadmin@lyris.sunbelt-software.com> Sent: Wednesday, May 2, 2012 11:48 AM Subject: RE: Tuning the TCP Stack on 2K8 R2 (tcp receive window) http://support.microsoft.com/kb/935400 (and the links it mentions) http://blogs.msdn.com/b/wndp/archive/2006/05/05/winhec-blog-tcpip-2.aspx I wouldn’t suggest turning it off, usually; just ensure that you have server-class NICs and the most recent drivers for them available and that you have the features also enabled on the NICs. From:Don Kuhlman [mailto:drkuhl...@yahoo.com] Sent: Wednesday, May 02, 2012 12:12 PM To: NT System Admin Issues Subject: Tuning the TCP Stack on 2K8 R2 (tcp receive window) Hi folks. Happy hump day ;) I'm working on testing an application called MassTransit(MT) from Group Logic. - basically, it's for automatically pushing files that users drop into folders and is used in workflows, etc. We are trying to evaluate some optimizations for throughput with one of the remote sites and MT where the remote site has some bandwidth limitations. For testing I have the following: 1 new 2K8 R2 VM test server in remote site with MT. Approximate RTT(Round Trip Time) ping times from local to remote site are 300 MS. Remote site has a 20M in/out pipe. Local MT server 2K8 R2 SP1 VM. Our local pipe is 100G. Both Servers TCP settings (as shown by netsh int tcp show global) are below. The only thing I changed is the ECN Capability setting - I enabled it. Default was disabled. I'm being advised by the corporate network team that we can also tweak the TCP receive settings on the remote site that has the longer RTT times. Everything that I've found so far says that 2K8 automatically tunes the TCP receive settings. The only thing I can find that may be related is the tcp autotuning value which has a brief write up article here: http://www.sevenforums.com/network-sharing/74556-enable-disable-tcp-auto-tuning.html It says you can use "netsh int tcp set global autotuninglevel=restricted" to try and override the stack's behavior. Values are - disabled, highlyrestricted, restricted, NORMAL(is the default), experimental Does anyone have any experience or comments on this? Thanks, Don K TCP Global Parameters ---------------------------------------------- Receive-Side Scaling State : enabled Chimney Offload State : automatic NetDMA State : enabled Direct Cache Acess (DCA) : disabled Receive Window Auto-Tuning Level : normal Add-On Congestion Control Provider : ctcp ECN Capability : enabled RFC 1323 Timestamps : disabled Same thing for the Chicago MT Server: MASSTRANSIT TCP Global Parameters ---------------------------------------------- Receive-Side Scaling State : enabled Chimney Offload State : automatic NetDMA State : enabled Direct Cache Acess (DCA) : disabled Receive Window Auto-Tuning Level : normal Add-On Congestion Control Provider : ctcp ECN Capability : enabled RFC 1323 Timestamps : disabled ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to listmana...@lyris.sunbeltsoftware.com with the body: unsubscribe ntsysadmin ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to listmana...@lyris.sunbeltsoftware.com with the body: unsubscribe ntsysadmin ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to listmana...@lyris.sunbeltsoftware.com with the body: unsubscribe ntsysadmin
