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Fragmentation Occurs When You Send Multicast Data Over Ethernet

Article ID: 319627 - View products that this article applies to.

This article was previously published under Q319627

SYMPTOMS

When you are using a multicast program to send data of up to 1472 bytes over Ethernet, you may observe fragmentation.

The maximum transmission unit (MTU) size for Ethernet is 1500. The various parts of a user data protocol (UDP) packet use the following bytes (totalling 1500 bytes):

20 bytes for the IP header.
8 bytes for the UDP header.
1472 bytes for data load.

You can expect that fragmentation will not occur when you send up to 1472 bytes of data over Ethernet.

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RESOLUTION

Service Pack Information

To resolve this problem, obtain the latest service pack for Microsoft Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

260910

(http://support.microsoft.com/kb/260910/EN-US/ )

How to Obtain the Latest Windows 2000 Service Pack

Hotfix Information

Windows 2000

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows 2000 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

(http://support.microsoft.com/contactus/?ws=support)

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

   Date         Time    Version      Size     File name
   -------------------------------------------------------
   19-Nov-2001  16:42  5.0.2195.46   118,896  Afd.sys
   06-Apr-2002  16:51  5.0.2195.48   105,232  Msafd.dll
   06-Apr-2002  16:50  5.0.2195.55   313,168  Tcpip.sys
   30-Jul-2001  20:15  5.0.2195.39    16,240  Tdi.sys
   06-Apr-2002  16:51  5.0.2195.48    17,680  Wshtcpip.dll

Windows XP

To resolve this problem, obtain the latest service pack for Windows XP. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

322389

(http://support.microsoft.com/kb/322389/EN-US/ )

How to Obtain the Latest Windows XP Service Pack

The English version of this fix should have the following file attributes or later:

   Date         Time   Version      Size     File name
   ---------------------------------------------------
   22-Apr-2002  13:50  5.1.2600.43  318,080  Tcpip.sys

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STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows 2000 Service Pack 4. This problem was first corrected in Windows XP Service Pack 1.

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MORE INFORMATION

For additional information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the article number below to view the article in the Microsoft Knowledge Base:

265173

(http://support.microsoft.com/kb/265173/EN-US/ )

The Datacenter Program and Windows 2000 Datacenter Server Product

For additional information about how to install multiple hotfixes with only one reboot, click the article number below to view the article in the Microsoft Knowledge Base:

296861

(http://support.microsoft.com/kb/296861/EN-US/ )

Use QChain.exe to Install Multiple Hotfixes with One Reboot

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