android multicast on several devices - android

I am doing multicast in my android apps and I have some troubles like most of people ;-)
I have created an android application which listens for multicast.
It works fine on 2 phones and one tablet (Samsung S2 & S3 and Motorola). The problem is with an Asus tablet. When I launch the application only on this device, I can receive data via multicast but when I launch the app on another device I cannot receive anymore data on the Asus but it works on the other.
I read somewhere that some tablets don't support completly multicast but I don't really understand the meaning of "not completely".
Can anyone help me on this issue?
I will perform several test with another asus and an acer tablet next week to see if it works.
Thanks.
Anthony

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Samsung Galaxy S6 edge unable to register on the network

I am in deep trouble right now and I don't know what is the problem. I purchased Galaxy S6 edge.
It was not new but used and I got it for $450.
I purchased it in a hurry.
It was rooted and it was running with EE apps.
I assume it is from EE. But it was working fine even with 4G. I wanted to upgrade it to marshmallow.
When I unroot it and upgraded to Marshmallow it stopped registering my phone on the network. I am in Pakistan and I purchased the phone from here.
Everything is working fine with the phone WIFI, Mobile Hotspot etc.
But the only problem is that it is not registering the network.
Sim is being read by the phone and it searches all the available network but couldn't register.
I downgraded the phone to lollipop and made the configuration just like it was before.
I again rooted the device so that it may work again.
But it was of no use.
I have been struggling to make it work for the past 4 days..
I have flashed modem.bin file of different carriers as well and tried to get that working but it doesn't work.
Please help me with that.. Any response will be very much appreciated.
Regards....
If your SIM card works fine in another handset (i.e. registers to the network) and if you have tested another new sim in your S6 edge unsuccessfully. The Issue is that your Network Operator is blocking your Authentication based on your devices IMEI (Unique number identifying the device). This happens when the IMEI was blacklisted due to theft or some reason by the operator.
I assume that when you re-flashed you may have reset your IMEI to something that is blacklisted. Make sure the IMEI is the same as on the phone sticker normally under the battery.

Android 6 / Samsung network issue

I've developed an Android app for remote controlling some special hardware devices. The communication is done via udp and wifi. The app already runs on ~60k devices without any problems but since the rollout of Android 6 I'm getting more and more reports from users who get some strange errors:
Usually the app searches for the hardware with a broadcast package. The app then requests all data from the hardware to stay in sync (~4000 packages in both directions). This sync process is heavily tested with all wifi conditions possible and does work as intended (also on Android 6).
User with a Samsung device and Android 6 are now having the issue, that the sync is unable to complete (no reply from the hardware within 20 seconds). The odd thing is that the broadcast search does work just fine, as well as the beginning of the sync. Usually the timeout happens when 5-15% of the sync was completed.
As I have no idea what could cause this issue I wanted to ask if there is any known problems with Samsung / Android 6 and udp communication via wifi?
Also were there any other changes on the network stack in Android 6 that could cause this issue? On my test devices (HTC mostly) everything runs fine so I'm currently out of ideas.
Edit:
I narrowed the issue down to the following devices:
Samsung Galaxy 6
Samsung Galaxy 6 Edge
Samsung Galaxy Note 5
Edit 2:
I got a Samsung Galaxy 6 device for testing purposes and of course it does work for me. I also tried all sorts of network setup, power saving, anti virus and general settings combination but it's just working all the time.
Edit 3:
After getting some Galaxy S5 and S6 test devices I was not able to reproduce the problem. Comparing the ROM version I found out that these devices all have a newer rom than the devices which got the issues.
Turns out that Samsung simply broke something in their wifi stack which causes the wifi to stop working properly after some udp packages. So only fix for this issue is to wait and hope they fix it in all countries soon.

Which Android devices support multiple Bluetooth Low Energy reading and writing at the same time?

I am writing a Android app which allow connecting two BLEs at the same time, then I can send signal to write and read to two BLEs at the same time also. (after some testing) It's working fine for ASUS Memo Pad 7 (4.4.2) and Samsung S4, but not for Moto G (4.4.4) and Nexus 7 which disconnected one and wrote to the other when I tried to write to both at the same time. I don't want to set delay between both devices because I want to signal to both as long as user keep pressing button. That was only four device I tested right now. Did anyone know why it's not working for those devices? is it hardware issue? how do I know which Android devices support to read and write multiple BLE at the same time?
You have to test each device to get this information, no other way.
Ideally on moto G and Nexus 7 it should have worked also. But there are lots of changes in BLE frameworks on Android 5.1 from Google. I think device supporting 5.1 should allow multiple device read/write operations.

Android bluetooth: Device specific connection issues

The problem is the following: I'm working on an Android project at the moment that involves the connection of two Android devices. I've got the connection and data transfer working with the guidelines of http://developer.android.com/guide/topics/connectivity/bluetooth.html but my application only works with two specific devices, the Sony Xperia LT22i (Android 4.0.4) and the Samsung Galaxy S Plus (Android 2.3.6).
When I try it on other Smartphones, they can successfully connect and they receive the test-byte '1', with which I check if the connection is working. But when the actual data transmission starts, they don't receive anything and there is no Exception thrown.
I can add the code if needed, but it's the same as on the mentioned Android Developers page, with a few app-specific changes. Has anyone had this problem or knows how to fix it? Thanks in advance.

When does android show a pairing dialog when using insecure RFCOMM bluetooth sockets?

I am trying to connect two unpaired android devices via Bluetooth for P2P networking purposes. MitM protection is not required. Android has the createInsecureRfcommSocketToServiceRecord and listenUsingInsecureRfcommWithServiceRecord for this (since API level 10), which works perfectly on modern devices. However, on a Galaxy Ace (Android 2.3.3 = API level 10, connecting with a Galaxy Nexus), it creates a pairing dialog. This happens both on incoming and outgoing connections. (Update: Updating the Galaxy Ace to Android 2.3.6 apparently fixes the problem. Is there a specific Android version that always/never does this?)
After the pairing is accepted, the connection works. For this reason, I think this is not related to Issue 40101: createInsecureRfcommSocketToServiceRecord causes pairing dialog on Android 4.2 which should only happen if the service record does not exist.
I assume this dialog cannot be avoided on devices where it comes up (if it can, explaining how to do this is a valid answer). For this reason, I would like to know when such a dialog is brought up. I did not find anything in the Android Java source (it goes native pretty quickly). I doubt it has anything to do with the Bluetooth version, since the Ace has Bluetooth 2.1 which is supposed to support the required "just works" connections.
If there is anything that would allow me to detect whether a device will support connections without popping the dialog, or if it was clearly fixed to a certain android version, that would immensely help me.
Also, I am looking for a way to easily exclude such devices.
Currently I have the same problem as you. I've developed an application to exchange messages between BT terminals and I'm testing it on different phones ( I have S3, S2, S plus, Nexus One and Galaxy Y) to analize the behaviour. Phones have this specs:
Samsung S2 : Custom ROM (Android v4.2.1) - Rooted
Samsung S3 : Stock ROM (Android v4.1.2)
Samsung S+ : Custom ROM (Android v4.1.2) - Rooted
Samsung GY : Custom ROM (Android v2.3.6) - Rooted
Nexus One : Stock ROM (Android v2.3.6) - Rooted
As far i can tell you from my experience, S2 and S3 after some time start to show the pairing dialog even if they are already paired and exchanging data. This happens all the time I include one of this two phones in my testbed, others are working fine and never ask for pairing ( expecially Nexus One that has a flawless behaviour).
I have made long running tests (from 4 to 6 hours) and I still can't figure out why this phones ask for pairing sometimes after 3 hours.. sometimes after 10 minutes.
The only thing that i would like to point you out is that even if u are using insecure connection you could still be asked for human interaction for pairing. Give a look at that (taken from http://en.wikipedia.org/wiki/Bluetooth) :
Just works: As implied by the name, this method just works. No user
interaction is required; however, a device may prompt the user to
confirm the pairing process. This method is typically used by headsets
with very limited IO capabilities, and is more secure than the fixed
PIN mechanism which is typically used for legacy pairing by this set
of limited devices. This method provides no man in the middle (MITM)
protection.

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