I've responded. I sort of (kind of) understand why you sent a PM instead of publicly asking questions, but for those following the thread:
The OP has provided a lot of "generalised" information points and indicates that he just has general field experience with some of these products. However, on the packet level, he's not familiar with what's going on.
In the PM at least **six** separate networking-related subjects were brought up. Those six: ARP, VLANs, IP unicast, IP multicast, IP broadcasting, and some "general IP protocol" stuff that I'd rather not get into. It would take me hours (minimum 2-3) to explain all of these things, and I pointed out that there are literally 3-4 week courses just on IP networking that cover one or two of these subjects. They aren't things you can explain in a page of text.
To quote part of my reply to the OP in my PM:
If I had to give you some advice on where to turn, it's pretty simple: you work for Bell Canada. I am absolutely 100% certain that somewhere within the bowels of Bell, you have very senior-level network technicians who are familiar with *all* of these things -- how the IPTV portion works ... , IP unicast vs. IP multicast, IP broadcasting (that's different than unicast and different than multicast!), and so on. I am also certain that within the bowels of Bell you have engineers who are familiar with the IPTV receiver products being deployed in the field -- when I say familiar I mean familiar with the inner workings of them -- and also who are familiar with the vendor of the product that makes them. I am 100% certain Bell has communication channels and contracts with those vendors.
As such, you should really turn to internal resources to get this solved. It sounds like it's a reproducible problem, and given what you're describing, to me it actually sounds like some kind of firmware bug in either the IPTV receivers being deployed at the customer's abodes, a firmware/software bug on the receiving end (meaning the concentrator at Bell that speaks to the IPTV receivers or decodes the frames/packets), or something else along those lines. If that turns out to be the case, the aforementioned communication liaisons can work this out with the vendor and get a patch of some sort.
Your general question: "can Wireshark help here?" The answer is yes, but you would need someone who is absolutely 100% familiar with how the IPTV device behaves on an IP level for the packet captures to be useful. Sending them to me won't help because I have zero familiarity with the product.
You need to do packet captures at 3 points:
1. The customer side (LAN side, facing IPTV receiver)
2. The IPTV receiver (facing Bell concentrator)
3. The Bell concentrator (facing the IPTV receiver)
Again: these have to be done SIMULTANEOUSLY. Because from what you describe, it sounds like the customer side may be sending something which the IPTV receiver "drops", or possibly the Bell concentrator side "drops". You won't know without seeing everything in between.
Reach out to internal resources first; drive this issue *hard* with your manager.
Just keeping everyone here in the thread informed.--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.