Support Information:
Considerations for Using Scalable Networking Pack (SNP)
Published: September 29, 2014
Updated: February 7, 2018
In the Windows Server 2003 Service Pack 1 and later, Microsoft provides the Scalable Networking Pack ("SNP"), a
set of features to improve network throughput using network acceleration and hardware-based offload
technologies. SNP is realized by the cooperation of windows server operating systems, network drivers and
network adapters.
Support Information for Operating Systems
To use SNP, you need to perform necessary setting and tuning on the network adapters and test the whole system
including network equipment. Please confirm that there is no problem for using the feature by conducting
thorough evaluations assuming the actual operations done in the production environment. For information about
the setting and tuning on the network adapters to use SNP, contact the manufacturer of the network adapters.
Applicable Operating Systems
- Windows Server 2003 (*1)
- Windows Server 2003 R2 (*1)
- Windows Storage Server 2003 (*1)
- Windows Storage Server 2003 R2 (*1)
- Windows Server 2008
- Windows Vista
- Windows Server 2008 R2
- Windows 7
- Windows Server 2012
- Windows 8
- Windows Server 2012 R2
- Windows 8.1
- Windows Server 2016
- Windows 10
(*1) SNP Support Information for Windows Server 2003 family Service Pack
SNP is available in Service Pack 1 and later.
In Service Pack 1, SNP can be enabled by installing KB912222.
In Service Pack 2 and later, KB912222 is included by default.
SNP Default Settings
SNP includes the following three features.
- TCP Chimney Offload
Offloads network packet processing tasks, including packet segmentation and reassembly, to a network adapter
implementing a TCP Offload Engine(TOE).
- RSS (Receive-side Scaling)
Shares the processing of inbound networking traffic across multiple CPUs by leveraging the extensions of
network adapters.
- NetDMA
Reduces the processing load of CPU required for data transfer between memories, supporting advanced memory
acceleration technologies such as Intel I/OAT.
The following are the default settings of SNP in each operating system. Note that the EXPRESSBUILDER may have
changed the settings.
To enable these features, the network adapter settings must be changed to "enabled" according to the operating
system settings.
- Windows Server 2003
- Windows Server 2003 R2
- Windows Storage Server 2003
- Windows Storage Server 2003 R2
| TCP Chimney Offload |
: enabled |
| RSS |
: enabled |
| NetDMA |
: enabled |
- Windows Server 2008
- Windows Vista
| TCP Chimney Offload |
: disabled |
| RSS |
: enabled |
| NetDMA |
: enabled |
- Windows Server 2008 R2
- Windows 7
| TCP Chimney Offload |
: automatic |
| RSS |
: enabled |
| NetDMA |
: enabled |
"Automatic" of TCP Chimney Offload indicates that the feature will be enabled when "TCP Chimney
Offload" is enabled in the network adapter settings and the system is using a high speed network environment
such as 10 GB Ethernet.
- Windows Server 2012
- Windows 8
- Windows Server 2012 R2
- Windows 8.1
- Windows Server 2016
- Windows 10
| TCP Chimney Offload |
: disabled |
| RSS |
: enabled |
NetDMA is not supported in the Windows Server 2012 / Windows Server 2016 Family.
Confirming SNP Settings
You can confirm the SNP settings by the following methods. Those differ depending on the operating systems.
Windows Server 2003 Family
[Applicable Operating Systems]
- Windows Server 2003
- Windows Server 2003 R2
- Windows Storage Server 2003
- Windows Storage Server 2003 R2
[Procedure]
- Open the Registry Editor and check the following registry values. If the registries have not been created,
this is the default state.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Name : EnableTCPChimney( TCP Chimney
Offload setting can be confirmed )
0 : disabled
1 : enabled
Name : EnableRSS( RSS setting can be
confirmed )
0 : disabled
1 : enabled
Name : EnableTCPA( NetDMA setting can be
confirmed )
0 : disabled
1 : enabled
Windows Server 2008 Family
[Applicable Operating Systems]
- Windows Server 2008
- Windows Vista
- Windows Server 2008 R2
- Windows 7
[Procedure]
- Open the Registry Editor and check the following registry values. If the registries have not been created,
this is the default state.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Name : EnableTCPA( NetDMA settings can be
confirmed )
0 : disabled
1 : enabled
- Open the Command Prompt and execute the netsh command as follows.
netsh int
tcp show global
Check the settings in the result displayed.
Receive-Side Scaling State( RSS setting can
be confirmed )
disabled
enabled
Chimney Offload State( TCP Chimney Offload
setting can be confirmed )
disabled
enabled
automatic
Windows Server 2012 / Windows Server 2016 Family
[Applicable Operating Systems]
- Windows Server 2012
- Windows 8
- Windows Server 2012 R2
- Windows 8.1
- Windows Server 2016
- Windows 10
[Procedure]
- Open the Command Prompt and execute the netsh command as follows.
netsh int
tcp show globall
Check the settings in the result displayed.
Receive-Side Scaling State( RSS setting can
be confirmed )
disabled
enabled
Chimney Offload State( TCP Chimney Offload
setting can be confirmed )
disabled
enabled
automatic
Ignore "NetDAM State" displayed in the result because NetDMA is not supported in the Windows Server 2012 /
Windows Server 2016 family.
Disabling SNP
You can disable SNP by the following methods. Those differ depending on the operating systems.
If you need
to enable SNP, click here.
[Important]
The methods include how to change the registry, but changing the registry incorrectly may cause a critical
problem. Pay enough attention when you edit the registry. NEC recommends preparing some countermeasures for
possible troubles such as making a backup of the registry before editing it just in case. Please note that all
manipulation of the registry must be done at your own risk.
Windows Server 2003 Family
SNP is disabled by editing the registry.
[Applicable Operating Systems]
- Windows Server 2003
- Windows Server 2003 R2
- Windows Storage Server 2003
- Windows Storage Server 2003 R2
[Procedure]
- Open the Registry Editor and set the following registry values to "0." If the registries cannot be found,
create them and set the values to "0" in like manner.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Name
Type
Value
|
: EnableTCPChimney
: REG_DWORD
: 0
|
Name
Type
Value
|
: EnableRSS
: REG_DWORD
: 0
|
Name
Type
Value
|
: EnableTCPA
: REG_DWORD
: 0
|
- Restart the operating system.
Windows Server 2008 Family
SNP is disabled by editing the registry and executing the netsh command.
[Applicable Operating Systems]
- Windows Server 2008
- Windows Vista
- Windows Server 2008 R2
- Windows 7
[Procedure]
- Open the Registry Editor and set the following registry value to "0". If the registry cannot be found,
create it and set the value to "0" in like manner.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Name
Type
Value
|
: EnableTCPA
: REG_DWORD
: 0
|
- Apply the hotfix provided in [Article ID: 967224] (*2) before executing the netsh command. (This is not
required for Windows Server 2008 R2 and Windows 7.)
- Open the Command Prompt and set the following settings using the netsh command.
netsh int
tcp set global chimney=disabled
netsh int tcp set global rss=disabled
- Restart the operating system.
Windows Server 2012 / Windows Server 2016 Family
SNP is disabled by executing the netsh command.
[Applicable Operating Systems]
- Windows Server 2012
- Windows 8
- Windows Server 2012 R2
- Windows 8.1
- Windows Server 2016
- Windows 10
[Procedure]
- Open the Command Prompt and set the following settings using the netsh command.
netsh int
tcp set global rss=disabled
netsh int tcp set global chimney=disabled
- Restart the operating system.
(*2)About Hotfix provided in [Article ID: 967224]
- Executing the netsh command on Windows Server 2008 or Window Vista can cause the issue shown in [Article
ID: 967224]. As the netsh command is used for disabling/enabling SNP, apply the hotfix provided in [Article
ID: 967224] beforehand.
- As for Windows Vista, the hotfix is applicable to Service Pack1 and later. If any service pack has not
been applied to the operating system, apply Service Pack1 before installing the hotfix.
- The product name for this hotfix is shown as "Windows Vista," but it is also applicable to Windows Server
2008.
- As the issue shown in [Article ID: 967224] does not occur on Windows Server 2008 R2 or Windows 7, the
hotfix is not needed for these operating systems.
[Article ID: 967224]
Some TCP/IP parameters in the registry are changed to incorrect values when you use the netsh command to
change TCP/IP global parameters on a computer that is running Windows Server 2008 or Windows Vista.
https://support.microsoft.com/kb/967224
Before Executing "System Update" in the EXPRESSBUILDER
If you are using Windows Server 2008, apply the hotfix provided in [Article ID: 967224] before executing the
"System Update" in the EXPRESSBUILDER.
[Reason]
On Windows Server 2008, SNP may be disabled by netsh command when "System Update" in the EXPRESSBUILDER is
executed. (Step 1 and 3 shown above are performed automatically.)
To know whether or not SNP is disabled when the "System Update" is executed in the EXPRESSBUILDER on your
machine, see the User's Guide and the Installation guide(Windows) included in the EXPRESSBUILDER.
If applicable, you can find a description about SNP in the following sections.
- User's Guide
Refer to applicable one of the following
- "Windows Server 2008" section in "Installing the Operating System with Express Setup"
- "Updating the System" section in "Installing Windows Server 2008"
- Installation guide(Windows)
Refer to applicable one of the following
- "Setup with EXPRESSBUILDER" or "Installing Stater Pack" section in "Setting Up Windows Server 2008"
[Note]
- The contents defer depending on the revisions of the EXPRESSBUILDER. Be sure to refer to the document
included in the EXPRESSBUILDER attached to your machine.
- In case you have applied or reapplied the "Starter Pack" before installing KB967224, perform the following.
- Apply KB967224.
You do not have to apply the "Starter Pack" after this.
- If you have changed the parameters under the following registry key before applying the "Starter Pack" set
the registry again.
This is because in a system to which KB967224 is not applied, executing the netsh command may restore the
parameters to defaults.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
disableTaskOffload
EnablePMTUBHDetect
EnablePMTUDiscovery
KeepAliveInterval
KeepAliveTime
Tcp1323Opts
TcpFinWait2Delay
TcpMaxDataRetransmissions
TcpTimedWaitDelay
TcpUseRFC1122UrgentPointer
Abstracted from [Article ID: 967224]
Reference
[Article ID: 968496]
Update to turn off SNP features for Windows Server 2003 and Windows SBS 2003
https://support.microsoft.com/kb/948496
[Article ID: 967224]
Some TCP/IP parameters in the registry are changed to incorrect values when you use the netsh command to change
TCP/IP global parameters on a computer that is running Windows Server 2008 or Windows Vista
https://support.microsoft.com/kb/967224
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