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[designmule]

Hello

I've read a couple thing lately related to network QOS. Both seem to suggest (to me) that for QOS to work properly it has to be implemented at the application level and that implementation might not be all that common.

"To ensure that I wasn't interpreting Wireshark incorrectly, I ran a capture on one of my IxChariot tests that used BK and VI DSCP priorities. Figure 6 shows a packet from the notebook running the VI priority stream properly tagged with DSCP = 5. The same capture showed the BK priority stream tagged with DSCP = 1 (not shown). So qWave or not, Vista, Windows Media Center and Windows Media Player didn't appear to implement any form of media priority tagging."

http://www.smallnetbuilder.com/wireless/wireless-features/30837-does-wi-fi-multimedia-wmm-really-do-anything-part-3?start=2

"As with Windows XP, network adapters have a "QoS Packet Scheduler" enabled by default, which reserves 20% of bandwidth by default for QoS applications that request priority traffic. Note this only has effect in the presence of running QoS applications that request priority traffic.

http://www.speedguide.net/articles/windows-7-vista-2008-tweaks-2574

Both of these articles are a bit dated, neither refer to JRiver specifically and I'm probably reaching but as I still sruggle with little hiccups when JRiver pushes audio to my AVR, I just wanted to know if JRiver performs media priority tagging?

Thanks for your time and I love the software BTW.
Matt

[designmule]

So I attempted to mimic the test run by Small Net Builder (originally on Windows Media Center) but in my case while pushing audio to my DMR (an Onkyo TX-NR809) from my media PC. I ran Wireshark while streaming and selected one of the packets sent to the DMR. Under the Differentiated Service Field I found that the value was set to 0 which is "best effort" or no priority. I'll admit that I'm a little over my head here but I think I've done this correctly. If I have interpreted the results incorrectly please let me know.

I hope my query and testing don't sound like a gripe about JRiver. I love the program greatly. If my assumptions are correct I will merely add priority tagging to the feature request list and go about my merry way hoping that it is implemented at some point.

Now I'd like to explain why I think this is important for anyone reading my posts. With priority tagging packets of data sent from JRiver will be prioritized over other packets of data on the network. So there is the potential there will be fewer network related hiccups at the (slight) cost to Facebook, emails, etc. This begins at the NIC on board the host computer, the network switch (if supported like it is in mine or at least passed as it is in most), the wifi access point (if used) and the DMR (mine is connected via a wired connection). This will also potentially positively affect users who access media outside of the LAN via JRemote or Gizmo.

So there it is. If anyone would like to know more about my network setup, would like to view my Wireshark trace logs, etc. I'd be happy to provide that information. I would like to know if my assertions are correct so that I can either drop the subject (if I'm wrong) or move my comments to the wish list.

Thank you for your time.
Matt

[muzicman0]

While applications can tag traffic, it is not required.  What typically happens is that the switch will be set up to assign certain DSCP codes for certain criteria.  I believe Video traffic would typically be tagged EF...

BUT...if you need QOS on your home network, then there is a problem, most likely...assuming you are running Gig ethernet.  Let's assume recording of 7 tv shows, all in HD, and playing back 3 HD shows...let's also say that each one is 35 Mbps (which is highly unlikely that all will be that high).

The 10 streams would be 350 Mbps...just a bit over 1/3rd of your bandwidth.  And this is just taking the 'all bandwidth ' approach.  In other words, typical gig ethernet has 2 Gigs of bandwidth per port (1 gig in, 1 gig out), so the total utilization really wouldn't be that high.  Audio traffic should be significantly less (my assumption, I really don't do much with just audio).

If you are running FastEthernet (100 Mbps), then I would suggest upgrading to gig...it's also possible that your switch has shared bandwidth between ports (uncommon, but could happen).

[designmule]

I know that at the switch one can assign priority to an IP address the physical port number on the switch but I don't understand how the switch would know one TCP packet from another without tagging. Maybe I'm wrong there but I don't think so.

[muzicman0]

It wouldn't, which is why some apps will put the tag in...but one can reasonably assume that packets coming from a media server would be audio/video material, and could tag it appropriately.

Note, I'm not arguing against tagging the traffic, just that it is not always done.  I am in technical support at a software company working with video over ethernet, and we don't tag our packets either.