Solved

How do I disable Large Send Offload on Server 2008 Core w/ Broadcom NICs?

Posted on 2010-08-14
9
4,759 Views
Last Modified: 2013-11-06
This is for a virtual environment.  Two host servers running Server 2008 R2 Core.  After some research I've determined that I need to disable Large Send Offload on the NICs of my hosts.  I'm trying to determine how and where to do the disabling.  I see in the Broadcom utility where I can disable it.  I also see in the VM's where I can go into the properties of the NIC and disable it (not sure if its needed here).  I'm seen other posts regarding running a NETSH command and editing the registry.  Can anyone shed some light on this?
0
Comment
Question by:chome81
  • 4
  • 3
  • 2
9 Comments
 
LVL 5

Expert Comment

by:Blake_1
ID: 33439372
Is http://support.microsoft.com/kb/951037 what you are referring to?  The chimney configuration is pertinent to Broadcom adapters.
0
 

Author Comment

by:chome81
ID: 33439381
No, that is TCP Chimeny Offload.  I am referring to Large Send Offload.  It is different.
0
 
LVL 5

Expert Comment

by:Blake_1
ID: 33439396
netsh int ip set global taskoffload=disabled
0
 

Author Comment

by:chome81
ID: 33439405
Blake_1, thank you, but I think there's more to it than that, hense the reason why I'm posting this.  I've seen that command as well, but I'm looking for a more detailed explanation.
0
Does Powershell have you tied up in knots?

Managing Active Directory does not always have to be complicated.  If you are spending more time trying instead of doing, then it's time to look at something else. For nearly 20 years, AD admins around the world have used one tool for day-to-day AD management: Hyena. Discover why

 
LVL 15

Expert Comment

by:msmamji
ID: 33440518
chome81 is right.
The above command will disable offloading on the OS. In order to completely get rid of it you also have to disable it at NIC level.
The problem with this is that you don't have any remote tool only allow you to view the network configuration and core doesn't have any command to change the properties of the NIC.

Luckily I landed on an article about jumbo frames on windows Server 2008 core R2 some time ago. The guy uses Broadcom Management Application Suite on core 2008 R2 to change Jumbo frame properties of broadcom NIC.
http://mrshannon.wordpress.com/2010/01/13/jumbo-frames-on-hyper-v-server/

You can use the article to disable the needed settings of broadcom NIC to completely disable offloading.

Regards,
Shahid
0
 

Author Comment

by:chome81
ID: 33441174
Thanks msmamji.  If I simply disable it in the broadcom utility, won't that alone be sufficient?  Its my understanding that the command will also effect other offloading, such as TCP Chimney Offloading, which I don't want to change.  Is that not correct?
0
 
LVL 15

Expert Comment

by:msmamji
ID: 33448776
Sorry for the late reply. Well to answer both you questions, I am copying a part of Ethernet NIC FAQs from broadcom website.
http://www.broadcom.com/support/ethernet_nic/faq_drivers.php#

What is Large Send Offload?Normally the TCP segmentation is done by the protocol stack. By enabling the Large Send Offload value, the TCP segmentation can be done by the Gigabit Ethernet Adapter.How can I configure Large Send Offload?   1. In Microsoft Windows, right-click the Network Adapter in Network Connections and then click Properties.   2. Click the Configure button and then the General tab.   3. Set the "Large Send Offload" parameter to Disable or Enable.
So it seems that the settings alone in the NIC hardware would take care of it. And yes as it seems disabling from NIC settings would disable all offloading features including TCP chimney.

Hope that helps.
Regards,
Shahid
0
 

Author Comment

by:chome81
ID: 33455987
This is where I'm missing it.

This command "netsh int ip set global taskoffload=disabled" will disable ALL offloading, just just LSO, correct?

I only want to disable LSO (Large Send Offloading)
0
 
LVL 15

Accepted Solution

by:
msmamji earned 500 total points
ID: 33479862
Again sorry for the delay.
task offload is enabled/disabled through ip context and chimney is controlled by tcp context, so I think one should not effect the other. With that being said you can be sure by checking the results of the following commmands.

net int ip show global
should give you the status of task offload among other things and

net int tcp show global
should give you the status of chimney among other things.

check the results of above commands both before and after applying the taskoffload=disabled switch.  

I hope that is what you were asking. The above command (netsh) only gives enabled or disabled control over taskoffload, not granular then that.

Regards,
Shahid
0

Featured Post

Swamped with email signature updates?

Have you been given a load of changes to make to your users’ email signatures? Having to manually implement multiple signatures for every department? Let Exclaimer save you from being swamped with email signature updates!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Scenario:  You do full backups to a internal hard drive in either product (SBS or Server 2008).  All goes well for a very long time.  One day, backups begin to fail with a message that the disk is full.  Your disk contains many, many more backups th…
From Coral's  "So You Want To Play With Computers" Series A bit of background first, so this story will make a little sense. One day, probably because he needed a good laugh, Finagle hooked me up with a church to upgrade/run their Media Booth.…
This tutorial will walk an individual through the steps necessary to join and promote the first Windows Server 2012 domain controller into an Active Directory environment running on Windows Server 2008. Determine the location of the FSMO roles by lo…
This tutorial will walk an individual through setting the global and backup job media overwrite and protection periods in Backup Exec 2012. Log onto the Backup Exec Central Administration Server. Examine the services. If all or most of them are stop…

932 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now