KVH mini-VSAT easy, but what about DHCP?
Big yacht IT is challenging, and thus I nearly had to tickle local marine networking ace Nik DeMaria (Blue Maple Systems) to capture his naturally grinning good nature, above and bigger here. I’ve known Nik “since he was knee high to a grasshopper,” as we say around here, but now he can make my head spin with talk of stuff like static IP addresses and Dynamic Host Configuration Protocol (DHCP)—his worries last week. You see, he and John Gass were just wrapping up the installation of a KVH V7 mini-VSAT aboard the 115’ sailing yacht Tenacious, and while they termed that chore “easy”—even pulled it off in less than a day—Nik was looking for an elegant way to manage the vessel’s multiple Internet users and sources. I think he’s still looking, and maybe some of you Panbo-reading IT types can help…
Tenacious has several computers and VOIP phones wired to its network plus four WiFi access points for crew and guests, and sometimes her Syrens/Wave/GeoSat Solutions (multi-name explanation below) high-power WiFi bridge will be preferable to the new mini-VSAT for hooking the yacht LAN to the Internet. Plus the system may get an alternate cellular Internet link added when Tenacious comes back for more work. What’s the best way to easily but knowingly move from one Internet source to a better one? Some yachts literally swap source Ethernet cables and reboot everything. Others have each source set up to be a DHCP server and all users set to acquire IP addresses automatically; to change sources you shut down everything, fire up the source you want, and then whichever computers you want. Theoretically at least, there are much better solutions, like Multi-WAN routers (ably discussed by Joe Mehaffey in this somewhat dated piece) or specialized software like Livewire’s Service Selector. But I’m in over my head here; how would you set up Tenacious, or, say, a 40’ boat with a few computers, alternate WiFi, cellular, and sat phone data connections…and a budget?
PS, Sorting out Syrens/Wave/GeoSat Solutions: GeoSat has been making high-end marine WiFi systems for years, but for a while they were distributed as Syrens WiFi by an independent company called Radio-at-Sea. Now GeoSat is doing direct distribution as Wave WiFi, but, whereas Radio-at-Sea owned the “Syrens” name, it’s marketing different WiFi hardware under it. So if you’re looking for Syrens (Nik is big fan of its hardware and service), go to Wave WiFi. Which doesn’t mean that there’s anything wrong with the new Syrens gear, except maybe the element of confusion.
PPS {corrected}, Below is the updated antenna farm on Tenacious, bigger here. The V7 (which replaced a Fleet 55 that’s now looking for a new home) is the big dome at 27” high, the mid-size is some sort of sat TV, and the little one is a Sea Tel WaveCall 3000 (Globalstar). The V7 controller and modem, shown inset, are mounted in the binnacle to reduce coax runs. Tenacious, by the way, can be chartered with a seaplane, more pictures here.
Ben,
The Internet sources get connected to individual Ethernet ports on a router. The internal network plugs into a hub, which in turn is plugged into the router. This allows the router to determine which Ethernet ports can connect to what. He'll set it up such that the internal Ethernet port can get to any of the others, the others can get to the internal one, but not any other.
This turns the router into a firewall. The internal Ethernet port will have NAT (Network Address Translation) IP addresses (like 10.x.x.x or 192.168.x.x) The internal addresses need never change regardless which source is providing Internet access.
Add to this RIP (Routing Information Protocol.) RIP dynamically updates the firewall's routing tables according to networks that can be found. It also adjudicates when multiple routes can be found to a network (such as a network across the Internet.) Each available route gets a weight (number of hops) and the router then chooses the path of least resistance (least number of hops to the destination.)
A cheap Cisco router (e.g. the 2600) will do all of this just fine.
FWIW, I wouldn't be making a DHCP server available unless they're making reservations. You don't want the Tenacious to become a Wi-Fi Hot Spot in every port it docks in, now do you? Also remember to turn off all but the one DHCP server, many of the devices involved probably each have their own DHCP server to make available.
I'm available if he wants more info.
Cheers,
Russ