Multicast on Android 2.2

Question

Has anyone gotten Multicast to work on Android 2.2, specifically JmDNS for Bonjour service detection. There are many questions & answers from the Android 1.5->2.0 timef

Answer 1

To (rudely) answer my own question, more information was provided at http://code.google.com/p/android/issues/detail?id=2917#c48 by another person. For posterity, as they say, here is brian.ro...@gmail.com's answer...

"I've spent quite a bit of time debugging mDNS issues with JmDNS on my Evo and HTC Hero (CDMA). What I found is there appears to be a filter in place in the broadcom wireless driver on the Evo (and since I'm getting a similiar reprt from an HTC Desire user - with the same chipset, presumably that handset as well). The filter, by default, blocks any non-unicast or network broadcast traffic, including multicast. Apparently the theory was it's a battery saver.

The problem appears to be the wpa_supplicant on the Evo does not support removing those filters when you get a MulticastLock. (Check the log output right after you get the lock and you'll see what I mean). Unfortunately what has happened is the hardware vendors have fragmented multicast support.... :("

So... it appears this is a device problem more than a coding problem. D'oh. :( If I get an opportunity to test on another device...

Answer 2

I've been doing a bit of research into this, and I believe it is a problem with Android in general, and fixed in or around Android 2.3.7.

It's a bit too anecdotal, but here's what I tested:

• HTC Desire, 2.2, stock: fail
• HTC Desire, 2.3.7, CyanogenMod: success
• Motorola Milestone, 2.1-update1: fail
• HTC Desire S, 2.3.3: fail
• Acer Iconia A501, 3.2.1: success
• Samsung something, 2.3.3: fail
• HTC Legend, 2.2 I think: fail

When I say 'fail', in fact they were all able to send multicast messages to the 'success' devices, but never receive anything back except their own messages - as jldupont describes.

Note that the multicast IM app Kouchat is only available for 2.3.7 onwards, even though it can be made to compile for as far back as 2.1, which gives further credence to this theory.

Answer 3

I think the other reason is your AP does not support.

Other:Computer send/recieve to/from Android

your computer must only use WIFI,Best off all other network