Been trying to chase down issues I'm having with the Airplay integration and it got me down pretty deep into the mDNS rabbit hole.
Long story short I have two HE hubs (one C7, one C8P) on the same LAN, hub meshed over a handful of devices. Both are wired to an unmanaged switch. I have Bonjour restarts turned off on both. I was having trouble with the Airplay integration on the C7 not seeing my Homepod Mini any more, so I installed it on the C8 Pro to see if there would be a difference. To my surprise, there is; the C8 Pro is able to see more Airplay devices, including the Homepod mini.
Had a look at activity monitor on the old iMac (same LAN) and saw this:
Ok, the iMac has been up for 77 days, but still... seems like a huge amount of traffic. So I fire up Wireshark to take a closer look at mDNS traffic:
The sudden drop in activity (around 14,000) corresponds to the moment where I shut down the C8 Pro (I can't really shut down the C7 during the day).
Running a capture shows that the two hubs are by far the most active on mDNS and the C8 Pro has twice the packet rate of the C7 (!).
Looking at the packet stream, I see tons of "cache flush" messages coming from both hubs, many (most?) being "Retransmitted response":
Does any of this look normal? I'm a little out of my comfort zone with this mDNS stuff.
see also this thread
Hopefully not...
