AT&T Equipment only works when plugged into RG (won't work when plugged into router or switch)

@mlesquire

Make sure that IPv6 is disabled on your AT&T provided router/gateway.

Wired TV - Are you referring to Ethernet? I suspect so but you need to confirm.

Wireless Access Point - Are you referring to the device that is used for television support in another room? Or are you referring to a WiFi device?

You state that four pieces of AT&T equipment work when plugged into the AT&T provided router/gateway but I only count two; the DVR and WAP.

3rd party router - Make, type, and model would be helpful.

After you give me further information, can you provide detail with regard to your requirements.

Wired TV - Are you referring to Ethernet? I suspect so but you need to confirm.

 - Yes.  Two of my set top boxes are run directly to the Residential Gateway and plugged in the back of it.  Ethernet.

Wireless Access Point - Are you referring to the device that is used for television support in another room? Or are you referring to a WiFi device?

 - Yes.  The device that sends the television signal to the wireless set top boxes.

You state that four pieces of AT&T equipment work when plugged into the AT&T provided router/gateway but I only count two; the DVR and WAP.

 - 2 TV set top boxes are plugged in via ethernet (run from other rooms in the house back to the Residential Gateway) (supplied and hooked up by AT&T tech)

- 1 Wireless Access Point for the wireless set top boxes. (also supplied and hooked up by AT&T tech)

- 1 DVR box (also supplied and hooked up by AT&T tech)

3rd party router - Make, type, and model would be helpful.

- This issue came to my attention because I wanted to get better wifi so I bought the Amplifi Mesh system by Ubiquity https://www.amplifi.com/ and put my AT&T residential gateway into bridge mode.  The modem has empty ports so I just plugged one of the AT&T components into it (since I now had to use one of the four ethernet ports for the modem.  None of them worked well (worked as described in the original post) when plugged into it.  However the new router worked beautifully.  As troubleshooting, I took the RG back out of bridge mode and tried again.  I also dug up an old switch I had and tried putting that into the RG with the ethernet cable (tried more than one cable too) and the AT&T equipment will not work plugged into either the new modem or the switch.  For some reason it only works when plugged directly into the AT&T residential gateway. For completeness, of course I tried rebooting the entire system as well as each component (set top box, WAP and DVR) separately and in various orders.  

 Thanks for the reply!

You cannot connect AT&T U-verse Receivers through most routers or Wireless Access Points (the dedicated one for use by the Wireless Receivers being the exception) for various and sundry reasons.  You cannot connect a wireless router or access point to the same switch as a U-verse TV Receiver is connected to.

You should be able to connect a Gigabit switch (such as the Netgear GS105 or GS108) to a port on your U-verse Gateway and connect your U-verse TV Receivers to that switch, and connect your Mesh system to another port on the Gateway.

You cannot connect the U-verse WAP or any Receiver directly or indirectly (e.g. via a Switch) to the Mesh device.

Looking at the specifications for that switch, there should be no issues with plugging it directly into the Gateway and plugging your receivers into it.

The symptom you are seeing is caused by the way U-verse distributes content.  When you first change channels, the Receiver sends requests up stream that (1) causes a unicast stream for the new channel to be sent directly the the Receiver's IP address, and (2) solicits to join the multicast stream for the new channel.  This causes each IGMPv2-aware device in the stream to prepare to accept the multicast stream and send it out the port the solicitation was received from.

The unicast happens in the blink of an eye, making channel changing fairly quick.  The multicast subscription can take several seconds, which is why the unicast is done, to cover the time until the multicast can be acquired by the TV Receiver.  When the TV Receiver sees the multicast, it syncs up the content and switches over.  After 10 seconds or so, the unicast stream is ended (whether or not the multicast ever got to the TV Receiver). 

So, you're getting the unicast, but not the multicast.  Not surprised that your Wireless system won't pass the multicast properly.  I'm rather surprised that a Gigabit switch would be blocking it.

That's certainly a reasonable option if you can get hold of one.  

Apparently the Gigabit switch was bad.  Got a new one and the TV signal is fine when the TV's (ethernet) are plugged into the switch and the switch is connected directly to the residential gateway.

Thanks!

@mlesquire @JefferMC

From the technical specs of the Netgear switch (Switch Specs) they should work. However, you must disable IPv6 on the AT&T router/gateway. Failure to do so can make it impossible to get everything working.

My recommendation is to plug the DVR, DGS-108, and WAP into the AT&T router/gateway. The smart TVs and Amplifi Mesh should be plugged into the DGS-108.

Now we need to implement this in stages for the sake of problem determination:

1. Only plug the DVR and WAP into the AT&T router/gateway. Now make sure everything works one at a time as well as all simultaneously. Once confirmed that everything works move to next step.
2. Connect DGS-108 and one smart TV. Using the smart TV by itself does it work? Now try the second smart TV by itself. Then try using both smart TVs simultaneously. And finally, run everything at once. I hope your realize that at some point you are going to run out of bandwidth on the AT&T circuit. Additionally, the AT&T router/gateway prioritizes Uverse-TV over other data traffic.
3. Amplifi Mesh will be last, once you get everything else working to your satisfaction. My suggestion would be to just plug it into the DGS-108 and use it as a cascaded router, at least initially. I would recommend that the connection to the AT&T router/gateway be a static IP address of 192.168.1.253 255.255.255.0. Additionally, make sure the SSID is different than that of the AT&T router/gateway.

Advise.

Wow, much thanks.  Two questions:

What do you mean that I will run out of bandwidth on the AT&T Circuit?  Do you mean to many TV's?

Also, why plug my router into the GS-108?  What is the difference in that and plugging it into the RG?