Worked out how to get the Garmin network and the boat's local area network to work together all at the same time. One iPad can access the internet (and get weather & live Bouy data) in BlueChart iOS while getting its GPS position from the Garmin 7215. Able to transfer routes back and forth to the Garmin 7215 without disconnecting from the internet. This page is a quick summary of how it works ...
What we wanted was to be able to connect to an external WiFi network and share that network with all devices connected to a boat network. We used the Ubiquity Bullet M2 to connect to the shore based network. The Ubiquity was purchased from Island Time and then mounted above the fly bridge. (20+ feel off the water) In our marina we see 40+ wireless networks! The Ubiqity connects to a Gigibit switch which connects to the Garmin 7215 and to a Ubiquity Picostation2. The Ubiquity Picostation is the access point for all the devices (iPhone, iPad, Android, Mac, etc) on the boat. There was no special reason we used Ubiquity products other than the Bullet has had such good reviews on Panbo.
Getting everything connected was simple. The only complex part was configuring the network settings. I knew from my prior testing that I was going to need to 1) use a 172.16.x.x address to work with the Garmin and also 2) filter some multicast traffic so it would not saturate on the wireless network. I ended up guessing on which IP addresses to use .. And so far everything works. Here is the configuration ...
Ubiquity Bullet M2 - Wireles Client
- IP address 172.16.0.20 Netmask 255.255.0.0
- DHCP Server assigning IP Addresses in the range of 172.16.0.50 to 172.16.0.100
Ubiquity Picostation2 - Access Point
- IP Address 172.16.0.254 Netmask 255.255.0.0
- Bridge mode.
- Firewall rules:
DROP UDP 220.127.116.11/32
DROP UDP 18.104.22.168/32
The only real complexity in the whole configuration was the filtering of traffic between the Wired and Wireless LAN. With my Garmin network the filtering here works! The full network configuration of both the Bullet (BM2) and the Picostation M2 are attached below. We are very happy with this configuration. Now I only wish Garmin would actually validate the firewall rules and/or explain some of the details. While this needs 100% for me I am not confident that it will work in every other configuration.