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Question regarding TCp Chimney Offload and Receive Side Scaling on Team/HyperV

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Question regarding TCp Chimney Offload and Receive Side Scaling on Team/HyperV

Patrick had a question regarding NIC offloading:




I want to check if  “TCp Chimney Offload” and “Receive Side Scaling” parameters are activated at hardware level on a Blade BL465c G7 (Windows 2008 R2/HyperV) using HPSREPORT……


1.)  For individual network cards, I found the following parameters on HP_Network_survey.txt file.

“TCP connection Offload”   or “TCP connection Offload (IPv4) ”

and “Receive Side Scaling” 

on Adapter Advanced settings part   


   ++++++++++++++++++++++++ Adapter Advanced Settings ++++++++++++++++++++++++


    Priority and VLAN                           = Priority and VLAN Enabled

    Flow Control                                = Rx/Tx Enable

    IPv4 Checksum Offload                       = Rx/Tx Enable

    Large Send Offload Version 1 (IPv4)         = 1

    Large Send Offload Version 2 (IPv4)         = 1

    Large Send Offload Version 2 (IPv6)         = 1

    Jumbo Packet                                = 1514 Bytes

    Number of Rx Descriptors                    = 896

    Receive-Side Scaling                        = 0

    TCP Checksum Offload (IPv4)                 = Rx/Tx Enable

    TCP Checksum Offload (IPv6)                 = Rx/Tx Enable

    TCP Connection Offload (IPv4)               = 0

    Number of Tx Descriptors                    = 256

    UDP Checksum Offload (IPv4)                 = Rx/Tx Enable

    UDP Checksum Offload (IPv6)                 = Rx/Tx Enable



I suppose these are the relevant parameters (it is for a NC382m individual card)    .Can you confirm that ?



2.) For a network team, how can I check that TOE and RSS are activated or not ?

I am not able to find these parameters “TCP connection Offload”   or “TCP connection Offload (IPv4) ” and “Receive Side Scaling”  on the team properties in HP_Network_survey.txt file…(team of 2 NC551i network cards..)


Are “RSS and TOE  team parameters” inherited from “ individual network cards parameters” member of the team ?



3.) what happens when HyperV Virtual switch  is linked to the team ?

Are RSS and TOE parameters of HyperV Virtual switch    inherited from the team or individual network cards member of the team ?








Input from John:

Recently I had to work with ISS on the question of RSS availability in a team.  The resultant description that I got is that the NCU teamed adapter will work with the adapter options as follows from the Network Adapter teaming White Paper:


4-6 HP ProLiant Network Adapter Teaming and advanced

networking features

When adapter ports are members of a team, some advanced features are no longer configurable on the port’s Advanced Settings tab. These advanced features are either promoted to the team’s Advanced Settings tab because the features are compatible and supported by all team members, or not promoted because one or more ports do not support the features.

There are also special cases where a feature is supported by all team members but the implementation is not compatible between the team members because they use different miniport drivers. In this case, it is not promoted to the team’s Advanced Settings tab.


So you are right in saying that the settings are inherited, but they could also be overridden using the Properties of the NCU generated adapter or in the Registry entry created for this device by the NCU in:




Where #### is the id of the NCU generated team,


You can look for this by searching through the DriverDesc values and checking for the value:
"HP Network Teaming Virtual Miniport Driver" which shows that the entry was created by NCU.  These Registry values are also recorded in the HP Network Survey output so in my case for example I am looking at a system now that has got these entries in the team's Registry values:


  *TcpConnectionOffloadIPv4                   = 0

  *RSS                                        = 0


These should correspond to the configuration parameters that you referenced in your email.


As to the HyperV switch I cannot comment but also am not sure what the impact would likely be.  Would the HyperV switch care about such matters?   Roll on Win2012 when NIC teaming is provided in the OS!!


Input from Aric:

For starters, you want to be sure that you are teaming adapters of the same model and FW.  In addition you want to be sure to use the latest NCU/FW/Driver combination you possibly can. Once the team is formed you’ll want to enable RSS on the team.


Assuming you are using WS2008R2SP1, you’ll want to be sure you are using the latest QFEs (KB2519736, KB2525390, KB2511305).  After that you’ll also want to enable RSS (netsh interface tcp set global rss=enabled) or TOE (netsh int tcp set global chimney=enabled).


With Hyper-V in WS2008R2, the Hyper-V switch does have the potential to pass-through the chimney (TOE) capability through to VMs (VM Chimney).




Any other comments or questions?