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Timeline for answer to Windows 7 DSCP and 802.1p QoS Mapping? by harrymc

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Jan 10, 2013 at 19:31 comment added harrymc ... and I also edited my answer above.
Jan 10, 2013 at 19:31 history edited harrymc CC BY-SA 3.0
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Jan 10, 2013 at 19:16 comment added harrymc Yes, I have seen that there are heaps of documents that say that 802.1p was available since always. I would have deleted my answer, since it's sure to get undervoted, except that this article that I found does throw some uncertainty on the question, and as 802.1p is so fragile in implementation unless so many factors come together just right. Not the first time that a Microsoft implementation was found to be defective after many years, and I don't know of any benchmark that ever proved it working.
Jan 10, 2013 at 19:01 comment added syplex Check out this document, which applies to Windows Server 2003 and clearly describes how to enable 802.1p. Here's an article describing how to enable 802.1p in Windows 2000 which also applies to Windows 2000 Server. I think that article is trying to say that Windows Server 2012 tags with 802.1p on its own generated traffic automatically (end to end) whereas previously it did not add the 802.1p tags. But not that 802.1p wasn't supported at all previously.
Jan 10, 2013 at 9:41 comment added harrymc Also see this article describing some reasons that can prevent 802.1p from working. Even if the tag was specified by the API, it's not at all sure that it was sent out, if not handled correctly at all stages. 802.1p can even conflict with the MTU!
Jan 10, 2013 at 7:33 comment added harrymc The article I found definitely states that there was no support for it by Windows servers before Server 2012, but that doesn't say anything about client versions such as 7. I based my answer on the fact that both versions do have a common code-base, but of course I can be wrong. I have no access to Microsoft internals and so can only guess that the 802.1p implementation, if it existed, was on Windows servers not operational or flawed before Server 2012. As always when Microsoft sources conflict, one has to use caution and common-sense.
Jan 9, 2013 at 23:54 comment added syplex 802.1p is supported by Windows 2000 and above. That link says the specific enumeration of QOS_TRAFFIC_TYPE is only supported in Windows Vista and above for workstations and Windows Server 2008 and above for servers. The API was different in Windows 2000 and in XP but 802.1p was still supported.
Jan 9, 2013 at 7:44 comment added harrymc The qWAVE API is said to set both DSCP and 802.1p, but this doesn't mean that both are supported by the operating system (but it does mean that setting one of them does not automatically set the other). According to the link above, 802.1p is only meaningful in the latest Windows version.
Jan 9, 2013 at 0:05 comment added syplex From what I have read 802.1p tagging is supported in Winodws since at least XP SP2. In XP, the Traffic Control (TC) API or the QoS API could be used. In Vista and above, the qWAVE API is used.
Jan 7, 2013 at 6:49 history edited harrymc CC BY-SA 3.0
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Jan 4, 2013 at 7:28 history answered harrymc CC BY-SA 3.0