Symptoms

Assume that you use a Windows Socket-based application to send data locally between a client and a server that are running Windows 7 or Windows Server 2008 R2. In this situation, the data transfer stops intermittently or is delayed for five seconds.

Cause

This problem occurs because of the Silly Window Syndrome (SWS) avoidance timer. The SWS timer is scheduled to send the remaining data bytes, and this represents less than one maximum segment size (MSS) or 1,460 bytes. Additionally, the receiver is supposed to send an acknowledgement (ACK) message that advertises the increased receive window and indicates that the remaining data bytes can be sent. However, if the receiver sends an ACK within 5 seconds when it has a sufficient buffer, the SWS timer cannot recover the five-second delay status because of a race condition. The race condition exists when packets reach the destination in reverse order.

Resolution

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=supportNote The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, you must be running Service Pack 1 for Windows 7 or Windows Server 2008 R2.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any previously released hotfix.

The English (United States) version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

Windows 7 and Windows Server 2008 R2 file information notesImportant Windows 7 hotfixes and Windows Server 2008 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies to" section in articles to determine the actual operating system that each hotfix applies to.

  • The files that apply to a specific product, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table.

    Version

    Product

    SR_Level

    Service branch

    6.1.760
    1.
    17xxx

    Windows 7 and Windows Server 2008 R2

    SP1

    GDR

    6.1.760
    1.
    18xxx

    Windows 7 and Windows Server 2008 R2

    SP1

    GDR

    6.1.760
    1.
    22xxx

    Windows 7 and Windows Server 2008 R2

    SP1

    LDR

  • GDR service branches contain only those fixes that are widely released to address widespread, extremely important issues. LDR service branches contain hotfixes in addition to widely released fixes.

  • The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows 7 and Windows Server 2008 R2" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x86-based versions of Windows 7

File name

File version

File size

Date

Time

Platform

Netio.sys

6.1.7601.17939

240,496

22-Aug-2012

17:16

x86

Netio.sys

6.1.7601.22382

240,576

12-Jul-2013

11:12

x86

Fwpkclnt.sys

6.1.7601.18042

187,752

03-Jan-2013

05:04

x86

Tcpip.sys

6.1.7601.18208

1,294,272

12-Jul-2013

11:48

x86

Fwpkclnt.sys

6.1.7601.22382

187,840

12-Jul-2013

11:11

x86

Tcpip.sys

6.1.7601.22382

1,309,120

12-Jul-2013

11:12

x86

For all supported x64-based versions of Windows 7 and Windows Server 2008 R2

File name

File version

File size

Date

Time

Platform

Netio.sys

6.1.7601.17939

376,688

22-Aug-2012

18:12

x64

Netio.sys

6.1.7601.22382

376,768

12-Jul-2013

12:07

x64

Fwpkclnt.sys

6.1.7601.18042

288,088

03-Jan-2013

06:00

x64

Tcpip.sys

6.1.7601.18208

1,909,696

12-Jul-2013

12:35

x64

Fwpkclnt.sys

6.1.7601.22382

288,192

12-Jul-2013

12:06

x64

Tcpip.sys

6.1.7601.22382

1,901,504

12-Jul-2013

12:07

x64

For all supported IA-64-based versions of Windows Server 2008 R2

File name

File version

File size

Date

Time

Platform

Netio.sys

6.1.7601.17939

711,024

22-Aug-2012

16:51

IA-64

Netio.sys

6.1.7601.22382

711,104

12-Jul-2013

11:09

IA-64

Fwpkclnt.sys

6.1.7601.18042

482,152

03-Jan-2013

04:45

IA-64

Tcpip.sys

6.1.7601.18208

3,797,952

12-Jul-2013

11:28

IA-64

Fwpkclnt.sys

6.1.7601.22382

482,240

12-Jul-2013

11:09

IA-64

Tcpip.sys

6.1.7601.22382

3,823,040

12-Jul-2013

11:09

IA-64


Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

References

For information about SWS, see Internet RFC 813 and Internet RFC 1122.

For information about MSS, See Internet RFC 879.

See the terminology Microsoft uses to describe software updates.

Additional file information for Windows 7 and for Windows Server 2008 R2

Additional files for all supported x86-based versions of Windows 7

File name

Package_1_for_kb2861819_bf~31bf3856ad364e35~x86~~6.1.1.0.mum

File version

Not Applicable

File size

2,003

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_1_for_kb2861819~31bf3856ad364e35~x86~~6.1.1.0.mum

File version

Not Applicable

File size

2,944

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_2_for_kb2861819_bf~31bf3856ad364e35~x86~~6.1.1.0.mum

File version

Not Applicable

File size

1,986

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_2_for_kb2861819~31bf3856ad364e35~x86~~6.1.1.0.mum

File version

Not Applicable

File size

2,927

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_3_for_kb2861819_bf~31bf3856ad364e35~x86~~6.1.1.0.mum

File version

Not Applicable

File size

1,988

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_3_for_kb2861819~31bf3856ad364e35~x86~~6.1.1.0.mum

File version

Not Applicable

File size

2,929

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_for_kb2861819_rtm_bf~31bf3856ad364e35~x86~~6.1.1.0.mum

File version

Not Applicable

File size

1,440

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_for_kb2861819_rtm~31bf3856ad364e35~x86~~6.1.1.0.mum

File version

Not Applicable

File size

1,459

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_for_kb2861819_sp1_bf~31bf3856ad364e35~x86~~6.1.1.0.mum

File version

Not Applicable

File size

1,883

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_for_kb2861819_sp1~31bf3856ad364e35~x86~~6.1.1.0.mum

File version

Not Applicable

File size

1,918

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Update-bf.mum

File version

Not Applicable

File size

2,094

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

X86_e54d468aad41772a8a53a914b3f20811_31bf3856ad364e35_6.1.7601.17939_none_6d59103b240c8f78.manifest

File version

Not Applicable

File size

1,054

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

X86_ece2dfb79765953260f9a87616503f28_31bf3856ad364e35_6.1.7601.22382_none_52faf6e61da18d21.manifest

File version

Not Applicable

File size

1,054

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

X86_microsoft-windows-netio-infrastructure_31bf3856ad364e35_6.1.7601.17939_none_58923ff3139b4b9b.manifest

File version

Not Applicable

File size

2,540

Date (UTC)

22-Aug-2012

Time (UTC)

17:35

Platform

Not Applicable

File name

X86_microsoft-windows-netio-infrastructure_31bf3856ad364e35_6.1.7601.22382_none_58dea70a2ce7f349.manifest

File version

Not Applicable

File size

2,540

Date (UTC)

12-Jul-2013

Time (UTC)

11:36

Platform

Not Applicable

File name

X86_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7601.18208_none_b53430d7c49cc598.manifest

File version

Not Applicable

File size

3,780

Date (UTC)

12-Jul-2013

Time (UTC)

22:11

Platform

Not Applicable

File name

X86_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7601.22382_none_b5614c86de00ace0.manifest

File version

Not Applicable

File size

3,834

Date (UTC)

12-Jul-2013

Time (UTC)

11:38

Platform

Not Applicable

Additional files for all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

File name

Amd64_046ce52c46feb15b6a01f4b50a0489f0_31bf3856ad364e35_6.1.7601.22382_none_9a7eea0840ca5d01.manifest

File version

Not Applicable

File size

712

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Amd64_508d613fec6eb2ca7dd97be408d204f9_31bf3856ad364e35_6.1.7601.17939_none_a95dd5fd26bf04e6.manifest

File version

Not Applicable

File size

1,060

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Amd64_d8c416d0121a7299f5e416f0a3d2351e_31bf3856ad364e35_6.1.7601.17939_none_ff65e9de4b9b2422.manifest

File version

Not Applicable

File size

1,414

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Amd64_f0ed83bda0697abd97fd471015aed5c2_31bf3856ad364e35_6.1.7601.17939_none_f48525cb7b29d619.manifest

File version

Not Applicable

File size

712

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Amd64_f1fbb871a3c173b6bf7c5bf5ddf8ea85_31bf3856ad364e35_6.1.7601.22382_none_02aa515b2fa4722f.manifest

File version

Not Applicable

File size

1,060

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Amd64_f68e4e16b1cb69c92901621777cec1de_31bf3856ad364e35_6.1.7601.22382_none_c8e83fe986f18a1e.manifest

File version

Not Applicable

File size

1,414

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Amd64_microsoft-windows-netio-infrastructure_31bf3856ad364e35_6.1.7601.17939_none_b4b0db76cbf8bcd1.manifest

File version

Not Applicable

File size

2,542

Date (UTC)

22-Aug-2012

Time (UTC)

18:33

Platform

Not Applicable

File name

Amd64_microsoft-windows-netio-infrastructure_31bf3856ad364e35_6.1.7601.22382_none_b4fd428de545647f.manifest

File version

Not Applicable

File size

2,542

Date (UTC)

12-Jul-2013

Time (UTC)

12:31

Platform

Not Applicable

File name

Amd64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7601.18208_none_1152cc5b7cfa36ce.manifest

File version

Not Applicable

File size

3,784

Date (UTC)

12-Jul-2013

Time (UTC)

22:15

Platform

Not Applicable

File name

Amd64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7601.22382_none_117fe80a965e1e16.manifest

File version

Not Applicable

File size

3,838

Date (UTC)

12-Jul-2013

Time (UTC)

12:35

Platform

Not Applicable

File name

Package_1_for_kb2861819_bf~31bf3856ad364e35~amd64~~6.1.1.0.mum

File version

Not Applicable

File size

2,015

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_1_for_kb2861819~31bf3856ad364e35~amd64~~6.1.1.0.mum

File version

Not Applicable

File size

2,962

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_2_for_kb2861819_bf~31bf3856ad364e35~amd64~~6.1.1.0.mum

File version

Not Applicable

File size

2,196

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_2_for_kb2861819~31bf3856ad364e35~amd64~~6.1.1.0.mum

File version

Not Applicable

File size

4,332

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_3_for_kb2861819_bf~31bf3856ad364e35~amd64~~6.1.1.0.mum

File version

Not Applicable

File size

2,194

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_3_for_kb2861819~31bf3856ad364e35~amd64~~6.1.1.0.mum

File version

Not Applicable

File size

4,550

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_4_for_kb2861819_bf~31bf3856ad364e35~amd64~~6.1.1.0.mum

File version

Not Applicable

File size

2,222

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_4_for_kb2861819~31bf3856ad364e35~amd64~~6.1.1.0.mum

File version

Not Applicable

File size

3,408

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_for_kb2861819_rtm_bf~31bf3856ad364e35~amd64~~6.1.1.0.mum

File version

Not Applicable

File size

1,448

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_for_kb2861819_rtm~31bf3856ad364e35~amd64~~6.1.1.0.mum

File version

Not Applicable

File size

1,468

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_for_kb2861819_sp1_bf~31bf3856ad364e35~amd64~~6.1.1.0.mum

File version

Not Applicable

File size

2,771

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_for_kb2861819_sp1~31bf3856ad364e35~amd64~~6.1.1.0.mum

File version

Not Applicable

File size

2,833

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Update-bf.mum

File version

Not Applicable

File size

2,719

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Wow64_microsoft-windows-netio-infrastructure_31bf3856ad364e35_6.1.7601.17939_none_bf0585c900597ecc.manifest

File version

Not Applicable

File size

1,166

Date (UTC)

22-Aug-2012

Time (UTC)

17:23

Platform

Not Applicable

File name

Wow64_microsoft-windows-netio-infrastructure_31bf3856ad364e35_6.1.7601.22382_none_bf51ece019a6267a.manifest

File version

Not Applicable

File size

1,166

Date (UTC)

12-Jul-2013

Time (UTC)

11:20

Platform

Not Applicable

Additional files for all supported IA-64-based versions of Windows Server 2008 R2

File name

Ia64_0e54a997dfbffcb492837f5fc6a4fa19_31bf3856ad364e35_6.1.7601.17939_none_bd33bbc9d426bebf.manifest

File version

Not Applicable

File size

1,411

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Ia64_d1ed13831dbbab8c402753f01d733f5a_31bf3856ad364e35_6.1.7601.22382_none_14249665541f5c5a.manifest

File version

Not Applicable

File size

1,411

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Ia64_microsoft-windows-netio-infrastructure_31bf3856ad364e35_6.1.7601.17939_none_5893e3e913995497.manifest

File version

Not Applicable

File size

2,541

Date (UTC)

22-Aug-2012

Time (UTC)

18:25

Platform

Not Applicable

File name

Ia64_microsoft-windows-netio-infrastructure_31bf3856ad364e35_6.1.7601.22382_none_58e04b002ce5fc45.manifest

File version

Not Applicable

File size

2,541

Date (UTC)

12-Jul-2013

Time (UTC)

11:34

Platform

Not Applicable

File name

Ia64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7601.18208_none_b535d4cdc49ace94.manifest

File version

Not Applicable

File size

3,782

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Ia64_microsoft-windows-tcpip-binaries_31bf3856ad364e35_6.1.7601.22382_none_b562f07cddfeb5dc.manifest

File version

Not Applicable

File size

3,836

Date (UTC)

12-Jul-2013

Time (UTC)

11:36

Platform

Not Applicable

File name

Package_1_for_kb2861819_bf~31bf3856ad364e35~ia64~~6.1.1.0.mum

File version

Not Applicable

File size

2,214

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_1_for_kb2861819~31bf3856ad364e35~ia64~~6.1.1.0.mum

File version

Not Applicable

File size

3,396

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_for_kb2861819_sp1_bf~31bf3856ad364e35~ia64~~6.1.1.0.mum

File version

Not Applicable

File size

1,427

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Package_for_kb2861819_sp1~31bf3856ad364e35~ia64~~6.1.1.0.mum

File version

Not Applicable

File size

1,446

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Update-bf.mum

File version

Not Applicable

File size

1,425

Date (UTC)

12-Jul-2013

Time (UTC)

22:08

Platform

Not Applicable

File name

Wow64_microsoft-windows-netio-infrastructure_31bf3856ad364e35_6.1.7601.17939_none_bf0585c900597ecc.manifest

File version

Not Applicable

File size

1,166

Date (UTC)

22-Aug-2012

Time (UTC)

17:23

Platform

Not Applicable

File name

Wow64_microsoft-windows-netio-infrastructure_31bf3856ad364e35_6.1.7601.22382_none_bf51ece019a6267a.manifest

File version

Not Applicable

File size

1,166

Date (UTC)

12-Jul-2013

Time (UTC)

11:20

Platform

Not Applicable


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