windows-server-2012 – Receiver将TCP窗口大小限制为64,512

发布时间：2020-12-13 19:59:23 所属栏目：Windows 来源：网络整理

导读：事实(请说明任何虚假陈述)：我在两个相隔80毫秒的站点之间有100 Mbps的连接这是一个长胖连接,可以从大的TCP窗口大小中受益,可能高达100 Mbps * 0.08秒= 1,000,000字节两台计算机都运行Windows Server 2012.“接收窗口自动调整级别”在两者上均正常.两者都

事实(请说明任何虚假陈述)：

>我在两个相隔80毫秒的站点之间有100 Mbps的连接
>这是一个长胖连接,可以从大的TCP窗口大小中受益,可能高达100 Mbps * 0.08秒= 1,000,000字节
>两台计算机都运行Windows Server 2012.“接收窗口自动调整级别”在两者上均正常.两者都禁用“窗口缩放启发式”.
>我一边是“iperf -s”,另一边是“iperf -c”.转移发生在5 Mbps.我从另一个方向得到了相同的结果.
>双方都宣称在其SYN中支持TCP滑动窗口.
>接收方请求TCP窗口大小为64,512字节(0xFC00)
在整个运行过程中,TCP窗口缩放值为“无移位”
(0x000的).
>网络能够处理更大的窗口大小(参见序列
图表)
>接收器使窗口小于网络支持
>此连接发生在IPSEC VPN中.隧道接口的MTU在两个方向上减少到1400字节.

题

>为什么接收器保持窗口小？

无答案

>网络坏了

在同一网络上运行的Linux机器将TCP窗口打开到1.5兆字节,并以6倍的带宽传输数据
>启用窗口缩放启发式扫描

窗口缩放启发式被禁用(参见下面的“netsh interface tcp show heuristics”的输出)
>接收窗口自动调整级别不正常

接收窗口自动调整级别正常(参见下面的“netsh interface tcp show global”的输出)
>这在ESXi中的虚拟机上运行不正常

在同一主机上运行的虚拟Linux机器上,性能提高了6倍.

2015年6月12日下午4:30更新

我通过将linux放在连接的一端来修改测试.果然,当linux向Windows Server 2012发送数据时,Windows提供了一个太小的TCP接收窗口(64,512字节).

当我将数据从Windows发送到linux时,linux提供了足够大的TCP接收窗口(1,365,120字节).但是,Windows限制发送到飞行中最多约60,000个字节.

更新于2015年6月13日下午3点(太平洋时间)

更接近根本原因的一步.在我的设置中,SO_SNDBUF和SO_RCVBUF都没有设置(通过iperf).这些是有效绑定接收窗口的发送和接收缓冲区.未指定这些值时,Windows Server 2012提供的默认值为64 kB.所以现在的问题是：

题

>如果未指定一个,为什么Windows Server 2012不会动态增加SO_SNDBUF / SO_RCVBUF以适应MSDN所述的长胖管道？

无答案

>“netsh winsock show autotuning”已禁用

它已启用.

更新于2015年8月24日下午4点(太平洋时间)

netsh显然已被Set-NetTCPSetting和family取代. Get-NetTCPSetting结合Get-NetTCPConnection显示我在“互联网”制度下运行,它为我提供了以下设置：

SettingName                   : Internet
MinRto(ms)                    : 300
InitialCongestionWindow(MSS)  : 4
CongestionProvider            : CTCP
CwndRestart                   : False
DelayedAckTimeout(ms)         : 50
MemoryPressureProtection      : Enabled
AutoTuningLevelLocal          : Normal
AutoTuningLevelGroupPolicy    : NotConfigured
AutoTuningLevelEffective      : Local
EcnCapability                 : Enabled
Timestamps                    : Disabled
InitialRto(ms)                : 3000
ScalingHeuristics             : Disabled
DynamicPortRangeStartPort     : 49152
DynamicPortRangeNumberOfPorts : 16384

发件人TCP设置

PS C:Usersacs> netsh interface tcp show global
Querying active state...

TCP Global Parameters
----------------------------------------------
Receive-Side Scaling State          : enabled
Chimney Offload State               : disabled
NetDMA State                        : disabled
Direct Cache Access (DCA)           : disabled
Receive Window Auto-Tuning Level    : normal
Add-On Congestion Control Provider  : none
ECN Capability                      : enabled
RFC 1323 Timestamps                 : disabled
Initial RTO                         : 3000
Receive Segment Coalescing State    : enabled

PS C:Usersacs> netsh interface tcp show heuristics
TCP Window Scaling heuristics Parameters
----------------------------------------------
Window Scaling heuristics         : disabled
Qualifying Destination Threshold  : 3
Profile type unknown              : normal
Profile type public               : normal
Profile type private              : normal
Profile type domain               : normal

PS C:Usersacs> Get-NetTCPSetting

SettingName                   : Automatic
MinRto(ms)                    : 
InitialCongestionWindow(MSS)  : 
CongestionProvider            : 
CwndRestart                   : 
DelayedAckTimeout(ms)         : 
MemoryPressureProtection      : 
AutoTuningLevelLocal          : 
AutoTuningLevelGroupPolicy    : 
AutoTuningLevelEffective      : 
EcnCapability                 : 
Timestamps                    : 
InitialRto(ms)                : 
ScalingHeuristics             : 
DynamicPortRangeStartPort     : 
DynamicPortRangeNumberOfPorts : 

SettingName                   : Custom
MinRto(ms)                    : 20
InitialCongestionWindow(MSS)  : 4
CongestionProvider            : DCTCP
CwndRestart                   : True
DelayedAckTimeout(ms)         : 10
MemoryPressureProtection      : Enabled
AutoTuningLevelLocal          : Normal
AutoTuningLevelGroupPolicy    : NotConfigured
AutoTuningLevelEffective      : Local
EcnCapability                 : Enabled
Timestamps                    : Disabled
InitialRto(ms)                : 3000
ScalingHeuristics             : Disabled
DynamicPortRangeStartPort     : 49152
DynamicPortRangeNumberOfPorts : 16384

SettingName                   : Compat
MinRto(ms)                    : 300
InitialCongestionWindow(MSS)  : 2
CongestionProvider            : Default
CwndRestart                   : False
DelayedAckTimeout(ms)         : 200
MemoryPressureProtection      : Enabled
AutoTuningLevelLocal          : Normal
AutoTuningLevelGroupPolicy    : NotConfigured
AutoTuningLevelEffective      : Local
EcnCapability                 : Enabled
Timestamps                    : Disabled
InitialRto(ms)                : 3000
ScalingHeuristics             : Disabled
DynamicPortRangeStartPort     : 49152
DynamicPortRangeNumberOfPorts : 16384

SettingName                   : Datacenter
MinRto(ms)                    : 20
InitialCongestionWindow(MSS)  : 4
CongestionProvider            : DCTCP
CwndRestart                   : True
DelayedAckTimeout(ms)         : 10
MemoryPressureProtection      : Enabled
AutoTuningLevelLocal          : Normal
AutoTuningLevelGroupPolicy    : NotConfigured
AutoTuningLevelEffective      : Local
EcnCapability                 : Enabled
Timestamps                    : Disabled
InitialRto(ms)                : 3000
ScalingHeuristics             : Disabled
DynamicPortRangeStartPort     : 49152
DynamicPortRangeNumberOfPorts : 16384

SettingName                   : Internet
MinRto(ms)                    : 300
InitialCongestionWindow(MSS)  : 4
CongestionProvider            : CTCP
CwndRestart                   : False
DelayedAckTimeout(ms)         : 50
MemoryPressureProtection      : Enabled
AutoTuningLevelLocal          : Normal
AutoTuningLevelGroupPolicy    : NotConfigured
AutoTuningLevelEffective      : Local
EcnCapability                 : Enabled
Timestamps                    : Disabled
InitialRto(ms)                : 3000
ScalingHeuristics             : Disabled
DynamicPortRangeStartPort     : 49152
DynamicPortRangeNumberOfPorts : 16384

发件人SYN

No.     Time           Source                Destination           Protocol Length Delta      Sequence number Acknowledgment number Bytes in flight Calculated window size Info
    814 5.036577000    10.10.0.21            10.11.0.1             TCP      66     0.000000000 0               0                                     64512                  49758→5001 [SYN,ECN,CWR] Seq=0 Win=64512 Len=0 MSS=1460 WS=1 SACK_PERM=1

Frame 814: 66 bytes on wire (528 bits),66 bytes captured (528 bits) on interface 0
Ethernet II,Src: 00:11:22:33:44:55,Dst: aa:bb:cc:dd:ee:ff
Internet Protocol Version 4,Src: 10.10.0.21 (10.10.0.21),Dst: 10.11.0.1 (10.11.0.1)
Transmission Control Protocol,Src Port: 49758 (49758),Dst Port: 5001 (5001),Seq: 0,Len: 0
    Source Port: 49758 (49758)
    Destination Port: 5001 (5001)
    [Stream index: 73]
    [TCP Segment Len: 0]
    Sequence number: 0    (relative sequence number)
    Acknowledgment number: 0
    Header Length: 32 bytes
    .... 0000 1100 0010 = Flags: 0x0c2 (SYN,CWR)
    Window size value: 64512
    [Calculated window size: 64512]
    Checksum: 0x1451 [validation disabled]
    Urgent pointer: 0
    Options: (12 bytes),Maximum segment size,No-Operation (NOP),Window scale,SACK permitted
        Maximum segment size: 1460 bytes
        No-Operation (NOP)
        Window scale: 0 (multiply by 1)
            Kind: Window Scale (3)
            Length: 3
            Shift count: 0
            [Multiplier: 1]
        No-Operation (NOP)
        No-Operation (NOP)
        TCP SACK Permitted Option: True

序列图的发送者视角

接收器TCP设置

PS C:Usersacs> netsh interface tcp show global
Querying active state...

TCP Global Parameters
----------------------------------------------
Receive-Side Scaling State          : enabled
Chimney Offload State               : disabled
NetDMA State                        : disabled
Direct Cache Access (DCA)           : disabled
Receive Window Auto-Tuning Level    : normal
Add-On Congestion Control Provider  : none
ECN Capability                      : enabled
RFC 1323 Timestamps                 : disabled
Initial RTO                         : 3000
Receive Segment Coalescing State    : enabled

PS C:Usersacs> netsh interface tcp show heuristics
TCP Window Scaling heuristics Parameters
----------------------------------------------
Window Scaling heuristics         : disabled
Qualifying Destination Threshold  : 3
Profile type unknown              : normal
Profile type public               : normal
Profile type private              : normal
Profile type domain               : normal

PS C:Usersacs> Get-NetTCPSetting

SettingName                   : Automatic
MinRto(ms)                    : 
InitialCongestionWindow(MSS)  : 
CongestionProvider            : 
CwndRestart                   : 
DelayedAckTimeout(ms)         : 
MemoryPressureProtection      : 
AutoTuningLevelLocal          : 
AutoTuningLevelGroupPolicy    : 
AutoTuningLevelEffective      : 
EcnCapability                 : 
Timestamps                    : 
InitialRto(ms)                : 
ScalingHeuristics             : 
DynamicPortRangeStartPort     : 
DynamicPortRangeNumberOfPorts : 

SettingName                   : Custom
MinRto(ms)                    : 20
InitialCongestionWindow(MSS)  : 4
CongestionProvider            : DCTCP
CwndRestart                   : True
DelayedAckTimeout(ms)         : 10
MemoryPressureProtection      : Enabled
AutoTuningLevelLocal          : Normal
AutoTuningLevelGroupPolicy    : NotConfigured
AutoTuningLevelEffective      : Local
EcnCapability                 : Enabled
Timestamps                    : Disabled
InitialRto(ms)                : 3000
ScalingHeuristics             : Disabled
DynamicPortRangeStartPort     : 49152
DynamicPortRangeNumberOfPorts : 16384

SettingName                   : Compat
MinRto(ms)                    : 300
InitialCongestionWindow(MSS)  : 2
CongestionProvider            : Default
CwndRestart                   : False
DelayedAckTimeout(ms)         : 200
MemoryPressureProtection      : Enabled
AutoTuningLevelLocal          : Normal
AutoTuningLevelGroupPolicy    : NotConfigured
AutoTuningLevelEffective      : Local
EcnCapability                 : Enabled
Timestamps                    : Disabled
InitialRto(ms)                : 3000
ScalingHeuristics             : Disabled
DynamicPortRangeStartPort     : 49152
DynamicPortRangeNumberOfPorts : 16384

SettingName                   : Datacenter
MinRto(ms)                    : 20
InitialCongestionWindow(MSS)  : 4
CongestionProvider            : DCTCP
CwndRestart                   : True
DelayedAckTimeout(ms)         : 10
MemoryPressureProtection      : Enabled
AutoTuningLevelLocal          : Normal
AutoTuningLevelGroupPolicy    : NotConfigured
AutoTuningLevelEffective      : Local
EcnCapability                 : Enabled
Timestamps                    : Disabled
InitialRto(ms)                : 3000
ScalingHeuristics             : Disabled
DynamicPortRangeStartPort     : 49152
DynamicPortRangeNumberOfPorts : 16384

SettingName                   : Internet
MinRto(ms)                    : 300
InitialCongestionWindow(MSS)  : 4
CongestionProvider            : CTCP
CwndRestart                   : False
DelayedAckTimeout(ms)         : 50
MemoryPressureProtection      : Enabled
AutoTuningLevelLocal          : Normal
AutoTuningLevelGroupPolicy    : NotConfigured
AutoTuningLevelEffective      : Local
EcnCapability                 : Enabled
Timestamps                    : Disabled
InitialRto(ms)                : 3000
ScalingHeuristics             : Disabled
DynamicPortRangeStartPort     : 49152
DynamicPortRangeNumberOfPorts : 16384

接收器SYN

No.     Time           Source                Destination           Protocol Length Delta      Sequence number Acknowledgment number Bytes in flight Calculated window size Info
    817 5.110501000    10.11.0.1             10.10.0.21            TCP      70     0.073924000 0               1                                     64512                  5001→49758 [SYN,ACK,ECN] Seq=0 Ack=1 Win=64512 Len=0 MSS=1460 WS=1 SACK_PERM=1 [ETHERNET FRAME CHECK SEQUENCE INCORRECT]

Frame 817: 70 bytes on wire (560 bits),70 bytes captured (560 bits) on interface 0
Ethernet II,Src: aa:bb:cc:dd:ee:ff,Dst: 00:11:22:33:44:55
Internet Protocol Version 4,Src: 10.11.0.1 (10.11.0.1),Dst: 10.10.0.21 (10.10.0.21)
Transmission Control Protocol,Src Port: 5001 (5001),Dst Port: 49758 (49758),Ack: 1,Len: 0
    Source Port: 5001 (5001)
    Destination Port: 49758 (49758)
    [Stream index: 73]
    [TCP Segment Len: 0]
    Sequence number: 0    (relative sequence number)
    Acknowledgment number: 1    (relative ack number)
    Header Length: 32 bytes
    .... 0000 0101 0010 = Flags: 0x052 (SYN,ECN)
    Window size value: 64512
    [Calculated window size: 64512]
    Checksum: 0xb5bb [validation disabled]
    Urgent pointer: 0
    Options: (12 bytes),SACK permitted
        Maximum segment size: 1460 bytes
        No-Operation (NOP)
        Window scale: 0 (multiply by 1)
            Kind: Window Scale (3)
            Length: 3
            Shift count: 0
            [Multiplier: 1]
        No-Operation (NOP)
        No-Operation (NOP)
        TCP SACK Permitted Option: True
    [SEQ/ACK analysis]

序列图的接收器透视图

TCP窗口

我已将此视为特定于驱动程序的问题;在我的情况下,QLogic网络控制器试图使用TCPChimney.此链接描述了Windows 2008中添加的TCPChimney功能 – 但我很确定它仍然适用： https://support.microsoft.com/en-us/kb/951037

我建议按顺序测试以下内容;每次测试后,重新启动并查看接收器是否按预期开始增加TCP RWIN.

1)在接收计算机上加载网络适配器的最新版本的驱动程序.
1)在接收计算机上禁用TCPChimney
2)禁用所有“TCP接收”卸载.这可以在网络适配器属性的高级设置中找到(与Speed& Duplex设置的区域相同)
3)禁用所有“TCP发送”卸载(也在网络适配器的高级属性中)

(与评论相反“超过65k的大TCP窗口大小对服务器不利,因为那时连接的内存需求增加.单独65k也可能不会让你足够开心.– user303507 2015年8月6日11:30”,大TCP接收Windows本身对服务器不利.在高带宽,高延迟链路(如卫星中继)的情况下,需要大的RWIN值,以便我们在“管道”中有更多的TCP数据.想象一下600 Mbps的连接,延迟为3000毫秒;高带宽链路将限制在大约20 KBps;因为一次只有65 KB的未确认TCP数据可能“在管道中”.)

（编辑：李大同）

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