# Tivo Mini Stuttering Issues



## internetsoncomps (May 1, 2014)

We have a Roamio Pro and 4 Minis although only 3 are hooked up and live. We also have 2 Premiere XLs. I have nothing hooked via MoCa, all hooked via cat6 cables. The Roamio Pro and minis are all on 1 L2 managed gigabit switch (DLINK DGS 3200 series). For some reason when watching live tv or recordings on the minis we are getting stuttering on most channels, especially HD channels. When switching to a channel or recording, the channel will tune in fine for a few seconds but then after a bit it will start stuttering. The connection will not get lost, it just keeps stuttering along with audio and video cutting/jumping. This happens on all of the minis. I have no problems with streaming recordings to/from the Premieres and Roamio Pro, just the minis. And the Premieres-to-Roamio Pro go through 1 more switch (and not the same one so Premiere-Premiere is 3 switches) than just the 1 L2 switch.

Looking at bandwidth and speed checks and everything looks fine, not even close to straining the network. Actually everything is super fast. I have checked all involved ports and they auto-negotiate fine, everything looks good in switch UI. Is there some way the managed switch may be truncating or screwing up the packets sent for the mini stream? I have turned off every managed feature on the switch to make it totally "passive" and the minis still have stuttered feed. I can't believe the enterprise-level gigabit switch is somehow too slow for the stream. I even wonder if there is some kind of buffering issue causing mis-timing or something because it's only the Minis and not the other TiVo boxes.

Been troubleshooting the settings of this switch as well as others in my network for a bit now and one other thing I am wondering if anyone knows, do the Tivo Minis communicate with the Roamio directly for streaming from the Roamio Pro? Or do they pass all traffic through the main network router? I am not a networking expert more of a hobbyist so I am not sure but I assume they would transmit directly through the switch to the other device but maybe there is some internet involved going back to TiVo?

I have been trying to hook up non-green/managed switch because with a green switch (DGS1024D) hooked up to the Roamio Pro+Minis the live tv would drop totally once in while (i.e. when someone went to bed and turned on that tv/mini after it had not been on all day would have to power cycle switch-which is in the basement-to get it back). If I hook the TiVos back into the "dumb" switch, it works fine with no stuttering on Minis, until the next batch of inactivity.

I am tempted to just go MoCa on the Roamio Pro and see if that works but I really want to figure out why the managed switch ethernet method is not working.


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## telemark (Nov 12, 2013)

Having a managed switch, makes it very difficult to give helpful advice. I really don't recommend these things unless really necessary.

Maybe start by replacing the switch with something else, the less green, less managed, the better.

Then go back and add an intermediate switch together with the managed switch.
You have to try twice:
once on the mini side
once on the Roamio side

That should give you 4 datapoints.
If there's different behavior in those 4 scenarios it might narrow down what needs to be fixed.


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## internetsoncomps (May 1, 2014)

Yeah, I thought I was in good shape in using the managed switch because I can turn off any/all of the power saving features and I assumed it would also have better overall speed and integrity as well in terms of dropping packets, etc. I guess there must be something in the switch that is affecting the data stream to the Minis that just cannot be set correctly (or I missed it). 

It's weird that I don't get it with any of the other boxes, but I'm sure the Minis operate somewhat differently and definitely have different hardware than the other TiVos. I initially thought it was only live tv that had the issue, but then I tried recordings and got the same stuttering on the minis. Certain hd channels work better than others-such as showtime hd was fine, then tuning to hbo hd and it was stuttering, espn hd was stuttering, discovery channel hd was fine-and most non-hd channels are fine. 

I may end up buying a 3rd switch for that location and just trying it out but I have been screwing around with so many settings on/off in the DGS3200 that I really wanted to get it to work. Oh well.


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## internetsoncomps (May 1, 2014)

I was checking out the switch UI after thinking about this a little more, and I may have been overthinking it because I may have just fixed the issue. I had been looking deep in the L2 features of the switch, but way up in the initial port settings is a setting that can be enabled or disabled called "flow control." This allows for insertion of pauses to keep data flow rates right when data is going from ports that are not the same speed (i.e. the gigabit port speed of the Roamio Pro to the 100m port speed of the Mini). This is disabled by default on all ports for some reason. I enabled flow control on all the ports, and everything seems to be working fine now. I believe the Minis were working okay on the unmanaged/dumb switch because on unmanaged switches flow control is always turned on.

It also makes sense that this was probably the issue, because of the stuttering I was getting. It wasn't actually losing the connection and never was displaying such, I think it was that the Mini was receiving the data faster than it could read it and that is why it was jumping along in spurts. 

I'll keep fingers crossed that this has fixed my problem and I can avoid trying any more switches.


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## telemark (Nov 12, 2013)

The symptoms could be explained by broken flow control.

But I'm a little surprised a Tivo would depend on L2 flow control. TCP/IP has it's own flow control mechanism. If the video is coming in over TCP then it should have been at the proper rate regardless. I could be wrong if it's over UDP.

If the problem comes back, Wireshark or the switch's stats, should be able to show you if the L2 congestion mechanism is actually being triggered.

For the record, your switch should be able to do everything, but it's a matter of time and effort to figure out what setting is wrong.

PS. The Mini's have no storage. So if you take the RAM size and divide it by the video rate, you'll get the maximum length of time it can buffer.


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## internetsoncomps (May 1, 2014)

Just to update-the Minis now work completely fine with the ports' flow control enabled and all switch power-saving features disabled. We have had no issues now for a couple months.


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## JWhites (May 15, 2013)

Oh excellent! Thanks for the update.:up:


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