HDHomeRun Mesh WiFi Discovery Issues

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Barker
Posts: 15
Joined: Sat May 02, 2020 2:42 pm

HDHomeRun Mesh WiFi Discovery Issues

Post by Barker »

There appears to be some discovery issues related to HDHomeRun on wireless mesh systems. I'm willing to bet it's due to the networking stack used on HDHomeRun devices, but I'm looking for any advice if possible.

To summarize the current wireless mesh network configuration.
  • Nest WiFi Router #1 (Primary, connected to modem over Ethernet)
  • Nest WiFi Router #2 (Connected to HDHomeRun HDHR4-2US over Ethernet)
  • Nest WiFi Router #3
  • Nest WiFi Router #4
The HDHomeRun device is always accessible on router #2. However, the HDHomeRun is not accessible ("No HDHomeRun Detected") on router 1, 3, or 4 unless I restart all 4 of these routers. And restarting all of these routers will only resolve the issue for approximately 24 hours. After this 24 hour period, the HDHomeRun device becomes inaccessible on any other router besides #2. HDHomeRun discovery issues have been confirmed to be present on Windows 10, Android TV 8.0, iOS, and Android 9.0.
  • IP reservations does not resolve this issue.
  • Unplugging ethernet and/or power to HDHomeRun also does not resolve this issue.
  • I am running the latest firmware for HDHomeRun, but this issue has been confirmed to be present on FW builds 3 years back.
  • Only temporary resolution appears to be restarting all mesh nodes on the network.
  • If ALL mesh points are connected over ethernet backhaul to the same switch, this issue is confirmed to not be present.
  • The exact same behavior has been confirmed to be present with Netgear Orbi RKB23, Google WiFi (3 Pack), and Nest WiFi Router (4 Pack).
EDIT: Discovery was made that this appears to be related to HDHomeRun being unable to re-lease a LAN IP. Unsure why this occurs over wireless backhaul.
Last edited by Barker on Mon May 18, 2020 12:35 am, edited 3 times in total.

jseymour
Posts: 431
Joined: Sat May 12, 2018 8:46 am

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by jseymour »

Barker wrote:
Sat May 02, 2020 3:05 pm
HDHomeRun discovery issues have been confirmed to be present on Windows 10, Android TV 8.0, iOS, and Android 9.0.
I can't speak to MS-Win10. Don't use it. But I do have Xiaomi MiBox S' that have run both Android 8 and Android 9, and have experienced no problems with HDHR discovery at all.

Barker wrote:
Sat May 02, 2020 3:05 pm
The exact same behavior has been confirmed to be present with Netgear Orbi RKB22, Google WiFi 3 pack, and Nest WiFi Router (x4).[/list]
There's a common theme, here.

HDHR discovery, I've learned since my last comments on a related issue, use a broadcast to UDP port 65001 for discovery. (Interestingly, both the LAN broadcast address and 255.255.255.255.) I can't tell, because our HDHR tuner's on a separate switch, but I presume the reply is a unicast to the client that sent the broadcast. (Perhaps NedS or another SD individual can confirm?)

There's no reason this scheme should fail on a flat LAN. But throw in things like intra-LAN routers, VLANs, "smart" bridges that attempt to "manage" traffic to improve performance (and doing things like breaking broadcast in the process), or what-have-you, and all bets are off.

Since the broadcast mechanism works for a while, then doesn't, my SWAG, and it really is a SWAG, is your mesh bridges (if they were really routers, it wouldn't work at all) are "learning-out" the broadcast mechanism so as to remove "unnecessary" traffic from neighbouring mesh nodes in a bid to improve performance.

Easy to find out. Throw something that can run wireshark or tcpdump on mesh node #2. Run wireshark with a filter:

Code: Select all

udp.port == 65001
Or, with tcpdump

Code: Select all

sudo tcpdump udp port 65001
You should see the client discovery broadcasts. My guess is when discovery fails you won't see them from the other mesh nodes anymore.

If that's what's happening, I'd look to see if there wasn't a configuration parameter you can set to get them to stop doing that.

NedS
Silicondust
Posts: 1052
Joined: Mon Dec 10, 2018 12:38 pm

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by NedS »

Pretty much what jseymour said. Every time I've dove into a mesh networking issue with a customer, it turns out to be some setting or feature for managing the network for "smart" features or security. We have yet to find any mesh system that won't actually work with an HDHomeRun, once things are set up correctly (relatively speaking, not to suggest that other ways are "wrong", but just in the context of how the HDHomeRun needs to work).

Barker
Posts: 15
Joined: Sat May 02, 2020 2:42 pm

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by Barker »

To clarify, "Nest WiFi Routers" (that's the model name) connected together will automatically configure non-primary nodes into bridge mode.

Unfortunately to my knowledge, Nest WiFi and Google WiFi have no configurable parameters beyond what the app provides. And the app is extremely minimal on configurable options. Interesting thing is all other broadcast mechanisms seem to work on my LAN, which is why I thought of pinning this on something SW/Driver level within HDHomeRun.

The tier 1 Google WiFi support agent had told me to attempt reserving an IP below x.x.x.50 and wait until tomorrow... I frankly have no expectation that this will work.

I'll Wireshark on 65001 when I detect the issue again.

Barker
Posts: 15
Joined: Sat May 02, 2020 2:42 pm

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by Barker »

NedS wrote:
Sat May 02, 2020 5:23 pm
Pretty much what jseymour said. Every time I've dove into a mesh networking issue with a customer, it turns out to be some setting or feature for managing the network for "smart" features or security. We have yet to find any mesh system that won't actually work with an HDHomeRun, once things are set up correctly (relatively speaking, not to suggest that other ways are "wrong", but just in the context of how the HDHomeRun needs to work).
Hey NedS, I can list every possible setting for Nest WiFi right now (there's not many).
  • WiFi Name/Password
  • DNS address
  • WAN (DHCP/Static/PPPoE)
  • LAN (Address/Subnet mask/DHCP Pool)
  • DHCP IP reservations
  • Port Forwarding
  • uPnP (Enable/Disable) [Enabled]
  • IPv6 (Enable/Disable) [Disabled]
  • Optimize for Stadia Traffic (Enable/Disable) [Disabled]
Last edited by Barker on Wed May 13, 2020 2:55 pm, edited 3 times in total.

jseymour
Posts: 431
Joined: Sat May 12, 2018 8:46 am

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by jseymour »

Barker wrote:
Sat May 02, 2020 5:27 pm
I'll Wireshark on 65001 when I detect the issue again.
You'll want to start-up wireshark before the problem manifests itself, to verify you're seeing the broadcasts on the node #2 mesh. Then, either leave it running until the discovery fails or start it up again. (Personally, I'd just leave it running, if possible. But not everybody has a spare laptop just sitting around for such purposes.)

Barker
Posts: 15
Joined: Sat May 02, 2020 2:42 pm

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by Barker »

jseymour wrote:
Sat May 02, 2020 7:42 pm
Barker wrote:
Sat May 02, 2020 5:27 pm
I'll Wireshark on 65001 when I detect the issue again.
You'll want to start-up wireshark before the problem manifests itself, to verify you're seeing the broadcasts on the node #2 mesh. Then, either leave it running until the discovery fails or start it up again. (Personally, I'd just leave it running, if possible. But not everybody has a spare laptop just sitting around for such purposes.)
Alright well, I've come back with more information. HDHomeRun's LAN address (192.168.86.49) is completely inaccessible on any other node except #2. I have seen this exact issue on my Orbi system before.

I've confirmed that all other devices on node #2's switch are accessible. Same behavior seen with/without the switch. I'll need to do some further testing regarding port 65001, but if the LAN address is completely inaccessible from node 1, 3, and 4 then streaming is SOL.

jseymour
Posts: 431
Joined: Sat May 12, 2018 8:46 am

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by jseymour »

How did you determine "accessibility?" E.g.: Did you try ping'ing the HDHR's IP address from the other mesh nodes?

Can you get to it with a browser either via http://my.hdhomerun.com or via http://ip.add.re.ss/system.html, either from the same mesh node or another? If you can access the page, what does System Status say about its IP address and subnet mask? Are they correct values?

Barker
Posts: 15
Joined: Sat May 02, 2020 2:42 pm

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by Barker »

jseymour wrote:
Mon May 04, 2020 8:19 am
How did you determine "accessibility?" E.g.: Did you try ping'ing the HDHR's IP address from the other mesh nodes?

Can you get to it with a browser either via http://my.hdhomerun.com or via http://ip.add.re.ss/system.html, either from the same mesh node or another? If you can access the page, what does System Status say about its IP address and subnet mask? Are they correct values?
System status reports the correct LAN IP.

Cannot ping, and cannot access the web interface (port 80) from any node besides #2.

jseymour
Posts: 431
Joined: Sat May 12, 2018 8:46 am

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by jseymour »

Barker wrote:
Mon May 04, 2020 9:41 am
System status reports the correct LAN IP.
And broadcast address? If you have a "flat" network, all devices on all mesh nodes should reflect the same broadcast address and subnet mask. (See below.)
Barker wrote:
Mon May 04, 2020 9:41 am
Cannot ping, and cannot access the web interface (port 80) from any node besides #2.
I presume that w/in the first 24 hours or so it's ping-able from everywhere?

A little "Networking 101". (You may know this and maybe you don't.)

Assuming the following:

Code: Select all

network address.....:  192.168.86.0
netmask.............:  255.255.255.0
broadcast address...:  192.168.86.255
A device at IP address 192.168.86.156 would be able to reach one at 192.168.86.49.

But, if the device at 192.168.86.156 was reporting:

Code: Select all

network address.....:  192.168.86.128
netmask.............:  255.255.255.128
broadcast address...:  192.168.86.255
and the device at 192.168.86.49 reported:

Code: Select all

network address.....:  192.168.86.0
netmask.............:  255.255.255.128
broadcast address...:  192.168.86.127
the two would be unable to see one another. Note that, while they have the same netmasks, they have different broadcast addresses. This is because they're on different networks. (As reflected by their differing network addresses.)

Barker
Posts: 15
Joined: Sat May 02, 2020 2:42 pm

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by Barker »

Yes, within the ~24 hours it's pingable from every node.

Subnet mask appropriately appears as 255.255.255.0, and I don't have any other subnets on my home network.

jseymour
Posts: 431
Joined: Sat May 12, 2018 8:46 am

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by jseymour »

At this point, Barker, I got nothing else. It seems, to me, like the mesh network is blocking the HDHR device for some reason. Makes no sense, but that sure is what it looks like, based on what you've reported.

Barker
Posts: 15
Joined: Sat May 02, 2020 2:42 pm

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by Barker »

jseymour wrote:
Tue May 05, 2020 7:24 pm
At this point, Barker, I got nothing else. It seems, to me, like the mesh network is blocking the HDHR device for some reason. Makes no sense, but that sure is what it looks like, based on what you've reported.
I know that both Orbi and all the Google networking products have something along the lines of "automatic threat prevention". Unfortunately I can't pin it on this since on both products there's no way to turn this off for testing.

Right now I got escalated to an upper tier of Google WiFi support and I'm letting them snoop around my network to see if they can determine the issue.

Barker
Posts: 15
Joined: Sat May 02, 2020 2:42 pm

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by Barker »

Just found out something else of interest. If I unplug the power to my HDHomeRun and re-plug, the HDHomeRun device becomes completely inaccessible across all nodes. To me, this seems like the DHCP server on node #1 is outright refusing to provide a LAN address.

jseymour
Posts: 431
Joined: Sat May 12, 2018 8:46 am

Re: HDHomeRun Mesh WiFi Discovery Issues

Post by jseymour »

Barker wrote:
Wed May 06, 2020 3:20 pm
To me, this seems like the DHCP server on node #1 is outright refusing to provide a LAN address.
I'm assuming this is after the 24-hour honeymoon period, but not before? If so, it increases my confidence that the mesh network is black-holing the HDHR. As such: The DHCP server would not see the HDHR's renewal requests.

This is something you'd also be able too see with Wireshark.

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