ShipModul 2Wi and Apple Airplay

[Charliemciver]

Does anyone have any experience/success running an Apple Airport Express on a Wifi network hosted by a ShipModul Multiplex-2Wi device?

When I reset the apple device, I can tell it to join the network... It duly reboots and apparently successfully joins the network (the light goes green), but no apple devices can 'see it' to play airplay to it. And no Apple config/diagnostic software (iPhone/iPad/PC) can see it.

I can't really think of any way to collect diagnostics either.

Any experience or thoughts welcome!!

[muttnik]

Worth dropping ShipModul a line. I don't own one of their devices but I found them extremely knowledgeable and helpful when asking a technical pre-sales question.once.

I'd specifically ask them whether there were any issues with their access points distributing multicast between stations. I believe the airport advertises its services via bonjour. If there's anything wonky with multicast propagation then you might have the problems you're seeing (although it's probably something completely different :-).

Best way to diagnose this further might be using wireshark or similar packet sniffer. If Internet Protocol isn't one of your primary skills the best way to diagnose this further is to invite a network engineer over for beers then casually mention to him/her that you'd stick their favourite tunes on if only you could get airplay working...

Please do report back if you find anything out from Shipmodul. Support for nmea-0183 over multicast UDP has just appeared in the latest OpenCPN beta and it would be good to get a heads up if there's likely to be an issue with the shipmodul multiplexers.

[Charliemciver]

I have dropped them a line and am waiting response. The device has been fantastic in every way until this issue, and I shall be sure to follow-up with outcome.

I had thought of using Wireshark but I'll need to set it up on a 'clean' network to see how it should work with out too much other junk going on and then compare.

My past with Wireshark has usually been on wired networks tracking down application level issues - here you rely on the 'see everything' aspect of the switch. I have it in my head that tracking down what effectively is a network switch issue will be very hard as you can't access all aspects of the network. Maybe I should give it a go and I'll surprise myself! This is all a pain in the butt too because I have to travel to my boat (3h round trip) so I don't get as much time as I would want, and removing the ShipModul is a bit of a pain. I wish they'd used removable Phoenix connectors rather than the screw down terminals to make it easy to remove.

[Charliemciver]

I should be specific too - NMEA over multicast UDP has worked flawlessly into iNavX with the ShipModul...

[muttnik]

Originally Posted by Charliemciver

I should be specific too - NMEA over multicast UDP has worked flawlessly into iNavX with the ShipModul...

I suspect you may be confusing multicast and broadcast. Following an email exchange with the iNavX developer a couple of weeks ago I don't believe iNavX supports multicast. The shipmodul manual discusses using broadcast but doesn't mention multicast.

The fact that they don't mention multicast NMEA delivery in the manual doesn't in any way mean that they don't have a correctly functioning network stack which deals correctly with link layer (as opposed to network layer) multicast. It was only a suggestion of something to look at assuming (a) you can establish unicast connectivity with the airport (if the access point won't give you a list of connected clients, what do you get back when pining the broadcast address?) and (b) you establish that you're getting no replies to mdns queries. Might be utterly the wrong tree to bark up :-)

[DotDun]

One bothersome statement on the ShipModul webpage:

The internal WiFi access point connects up to 7 devices simultaneously.

This indicates they're not using a full 802.11 access point chipset.

[Charliemciver]

You're right - I mean broadcast.

It's a little bit annoying... The options on the wifi config are very slim - I can't even tell it to join an external wifi network (eg hosted by my Airport) and do it that way (not that i want my airplay as the critical piece anyway).

I'll see what they say, but maybe I have to accept hosting a second wifi net for the music and use my iPad for Nav and iPhone for music.

[goboatingnow]

How are the IP address being setup. What's handing them out.

Also be aware as far as I can tell , the Shipmodule will only work as an access point and the airport express cannot act as a wireless bridge. What you have are two wireless access points attempting to connect wirelessly. From memory I don't think the apple unit is capable of that.

What you need is the shipmodule to act as a wifi client. But I don't know if it can do that

Dave

[muttnik]

Originally Posted by Charliemciver

I'll see what they say, but maybe I have to accept hosting a second wifi net for the music and use my iPad for Nav and iPhone for music.

If you're running an airport I'm guessing you've got a bit of power available (motorboat?) in which case you could consider forgetting the shipmodul's wifi, plugging the usb out into something which can convert serial to network (I'll suggest a raspberry pi here) and connecting that via UTP to the airport. Far more flexible solution on the networking front. Additional components aren't ideal though. I'd be interested to know what they advise you.

[DotDun]

Originally Posted by goboatingnow

How are the IP address being setup. What's handing them out.

Also be aware as far as I can tell , the Shipmodule will only work as an access point and the airport express cannot act as a wireless bridge. What you have are two wireless access points attempting to connect wirelessly. From memory I don't think the apple unit is capable of that.

What you need is the shipmodule to act as a wifi client. But I don't know if it can do that

Dave

You can set the Airport Express up in client mode and it should advertise Airplay. Some caveats to bridging to it's Ethernet ports (802.11n model only) explained here:

AirPort Express: How to join an existing Wi-Fi network in client mode

My guess is the .11 chipset in the Shipmodul is not forwarding bonjour correctly.

The 3rd example on this page shows what I believe the OP is trying to do.

Wi-Fi base stations: How to set up and configure AirPort Express for AirPlay and iTunes

[Charliemciver]

The Airport Express when I use it at home is quite happy joining other wifi networks as a client....

And from what I can tell the ShipModul is always setting up its wifi network. It has quite a bizarre IP capability. It's either a static IP setup, or it relies on everyone doing the auto assign thing - there's no DHCP server!!!

So maybe next I try seeing if a static IP setup will change things at all. It *shouldn't* but it's something to try.

I wonder if I can get the airport to join the network and then be a DHCP server.... Next trip to the boat is Friday!

[goboatingnow]

Just to clarify. If the ship modul unit only acts access point. You have to put the apple airport express into client mode. It then only bridges its two Ethernet ports onto the network.

It's will advertise its airplay services as a client through the ship modul wifi. However apple warn that this comes close to the performance limits of the express and dropout can be expected

If the OP has not used client mode then that explains why he can't connect properly.

If he has selected client mode then he will not be able to access the native apple airport wifi , its in effect been turned off, the wifi is being provided by the ship module unit. Connect to its wifi instead ( and then reach the airport express )

If the ship modul is a wifi access point only profile , then it should provide dhcp server services. I don't think airport express does so on client mode

If it doesn't its static ip setup all the way ( which is a pain )

Really the problem is the poor implementation on the ShipModul wifi. It should be capable of acting as a client to an existing wifi AP and be setup via dhcp

Dave

[Charliemciver]

Originally Posted by goboatingnow

Just to clarify. If the ship modul unit only acts access point. You have to put the apple airport express into client mode. It then only bridges its two Ethernet ports onto the network.

It's will advertise its airplay services as a client through the ship modul wifi. However apple warn that this comes close to the performance limits of the express and dropout can be expected

Yep - done this - doesn't work.

Originally Posted by goboatingnow

If the OP has not used client mode then that explains why he can't connect properly.

If he has selected client mode then he will not be able to access the native apple airport wifi , its in effect been turned off, the wifi is being provided by the ship module unit. Connect to its wifi instead ( and then reach the airport express )

Agree. Am ignoring Apple wifi setup - in fact its impossible to configure this on the Apple device in client mode to my knowledge.

Originally Posted by goboatingnow

If the ship modul is a wifi access point only profile , then it should provide dhcp server services. I don't think airport express does so on client mode

If it doesn't its static ip setup all the way ( which is a pain )

Really the problem is the poor implementation on the ShipModul wifi. It should be capable of acting as a client to an existing wifi AP and be setup via dhcp

I've got a reply from ShipModul support today which I'll review and see if it helps. They think it should work and but have heard of some not dissimilar problems with Apple TV. They're also saying I can DHCP is supported and also some command exists I can use to get it to join another Wifi network. So this gives me some options to experiment with.

I shall report back progress in due course!!

[Charliemciver]

Originally Posted by muttnik

If you're running an airport I'm guessing you've got a bit of power available (motorboat?) in which case you could consider...

I'm on an Elan Impression 434 Sailing boat, recently acquired. Loving it. I've modified an Airplay to run on 12V, which vastly reduces its power consumption compared to running it on an inverter. Its a messy, irreversible job, but once done and locked away, who cares!