Multicast Discovery not working

Reception, channel detection, network issues, CableCARD setup, etc.
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beavel
Posts: 2
Joined: Sun Nov 22, 2020 8:01 pm

Multicast Discovery not working

Post by beavel »

According to this post https://www.silicondust.com/support/dow ... changelog/ a new feature is supposed to be multicast discovery. From reading this (https://www.silicondust.com/support/hdh ... cast_recv/, I believe I should be able to trigger the discovery by pressing rescan. What I am seeing when I press rescan is just a broadcast packet being sent to 255.255.255.255 UDP port 65001. Is the setup software supposed to support multicast? If so, how do I get my install to default to it?

-Beavel

shawn_75
Posts: 170
Joined: Sun Oct 14, 2012 5:19 pm
Device ID: 151032EF

Re: Multicast Discovery not working

Post by shawn_75 »

I'm going out on a limb here, but I suspect that line in the changelog means the record engine can detect multicast streams and join the multicast groups.

nickk
Silicondust
Posts: 16434
Joined: Tue Jan 13, 2004 9:39 am
x 131

Re: Multicast Discovery not working

Post by nickk »

HDHomeRun Setup uses broadcast to discover devices because this is the most reliable method of discovery (multicast communication is sometimes blocked LAN port to LAN port by home routers).

The HDHomeRun units respond to broadcast discover, subnet-broadcast discover, and multicast discover.

Some client platforms don't allow sending broadcast packets so multicast is used instead.

Nick

beavel
Posts: 2
Joined: Sun Nov 22, 2020 8:01 pm

Re: Multicast Discovery not working

Post by beavel »

While I get the logic that broadcast packets are most reliable, I don't understand why multicast couldn't/wouldn't be a fallback option. The other part I'm not clear on is the second link I posted very clearly states one can expect a SSDP packet be sent to the multicast group. In what context is that support documentation valid? Part of me was wondering if it was for a different platform, but it refers to Device Manager so it seemed like it was for running HDHomeRun Setup from Windows.

nickk
Silicondust
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Joined: Tue Jan 13, 2004 9:39 am
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Re: Multicast Discovery not working

Post by nickk »

beavel wrote: Sun Nov 22, 2020 9:30 pmWhile I get the logic that broadcast packets are most reliable, I don't understand why multicast couldn't/wouldn't be a fallback option.
If the client can send broadcast packets then it should find devices. If it can't find devices using broadcast I am not sure why multicast could be expected to work.
beavel wrote: Sun Nov 22, 2020 9:30 pmThe other part I'm not clear on is the second link I posted very clearly states one can expect a SSDP packet be sent to the multicast group. In what context is that support documentation valid?
Non-legacy HDHomeRun devices support DLNA and advertise themselves over multicast SSDP as a MediaServer.
If you are using a home router and the path between the HDHomeRun and your PC involves the router then this communication may be being blocked by your router.

Nick

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