This article applies to all SSL products that use ipMIDI or Delta Control, not just Nucleus.
Many computers have multiple Ethernet adapters, and if you count the Wi-Fi adapter, they may have three adapters.
This can present a problem in direct-connection schemes with SSL ipMIDI and Delta controllers, because multicast data (DAW control, Delta control, MIDI Time Code, and MIDI Machine Control) will by default only go out the primary adapter. The primary adapter is the internet, not the SSL! Please note that when Wi-Fi is on, it automatically becomes the primary adapter. This is why Wi-Fi should be disabled when using SSL controllers.
Fundamentally, Nucleus is a network device, and network devices should not be directly connected to each other, they should be connected through a Local Area Network.
Therefore, the best solution is to connect every device to a switch or router and not use the computer's secondary adapter for SSL. On Nucleus 2 you can connect everything through the Nucleus's switched ports. To repeat, do not connect the SSL directly to your computer.
If you must keep the dual interfaces with the SSL on the secondary, you can make it work by altering the routing table for the multicast addresses SSL uses (.37 for ipMIDI and .38 for Delta Control).
Essentially, this forces multicast out of the non-primary interface (the SSL one).
This terminal command worked in High Sierra and most later macOS versions:
sudo networksetup -setadditionalroutes <Mac adapter name> 126.96.36.199 255.255.0.0 127.0.0.1
sudo networksetup -setadditionalroutes <Mac adapter name> 188.8.131.52 255.255.0.0 127.0.0.1
<Mac adapter name> is the common name as seen in System Preferences Network, and is usually something like Ethernet.
route add -p 184.108.40.206 mask 255.255.255.255 <PC adapter IP address>
route add -p 220.127.116.11 mask 255.255.255.255 <PC adapter IP address>
<PC adapter IP address> is the IP of the adapter connected to the SSL (not the SSL IP!)
- Apple has periodically changed their method for persistent routing table changes, so there is no guarantee they will not change it again in an update, which would mean you would have to find the new way Apple does this and re-implement.
- If you get a new computer or flat install, you will lose this route and have to redo.
- This could affect any app that uses 18.104.22.168 and .38; chances of that are very small, but perhaps not zero.
- Nucleus is a network device. Network devices should be connected via a LAN, not directly in most cases.
- SSL ipMIDI and Delta Control use multicast.
- Those multicast packets are going out of the primary adapter, which is usually your internet. That's just how macOS does it, it doesn't know where to route them, it's all the same to the Mac.
- So they never get to the SSL.
- When you remove the internet connection, the SSL-attached adapter becomes the primary and it starts working. Proof-positive this is what is happening.
Please also see these related articles: