Eddystone Beacon中广播的MAC ID是否更改? [英] Does MAC ID broadcasted in Eddystone Beacon change?

问题描述

我将描述我的设置:

我已经制作了一个模拟Eddystone信标的android应用程序. 我可以使用PlayStore上的Beacon Toy应用程序在手机上检测到Eddystone信标.但问题是，从我上次检查起，显示的MAC ID已更改. 由于名称空间和实例ID相同，但MacID不同，因此我可以标识其相同的信标. 有人可以建议这里发生了什么吗?我的印象是MacID保持不变.

I have made an android application that simulates Eddystone beacon. I was able to detect the Eddystone beacon on my phone using Beacon Toy app from PlayStore. But the thing is , from the last time I checked , the MAC ID displayed has changed. I can identify its the same beacon because of the namespace and instance id being the same but under different MacID. Could someone suggest what is happening here ? I was under the impression that MacID stays constant.

推荐答案

是的，Android发送器会随机化其蓝牙MAC地址.这不是Eddystone特有的，而是所有类型的Android信标发送器，更精确地用于Android BLE广告.

Yes, Android transmitters randomize their bluetooth MAC address. This is nothing specific to Eddystone, but to Android beacon transmitters of all types, and more precisely to Android BLE advertising.

为了证明这一点，我在Nexus 5X上进行了一些测试.使用Locate Beacon应用程序以iBeacon格式传输信标(同样的结果也适用于Eddystone和其他格式)，我可以看到每次停止并开始播发时，传输的MAC地址都会发生变化.

To prove this, I ran some tests on my Nexus 5X. Using the Locate Beacon app to transmit a beacon in the iBeacon format (the same results apply to Eddystone and other formats too) I can see that the MAC address transmitted changes each time I stop and start advertising.

我的Nexus 5X在设置->关于手机->状态->蓝牙地址中显示其蓝牙MAC地址.它是64:bc:0c:xx:xx:xx(注意:我将MAC的后三个特定设备字节清空了，只显示了前三个字节，这是分配给Nexus 5X制造商LG电子的Company OUI.)

My Nexus 5X reveals its Bluetooth MAC address in Settings -> About Phone -> Status -> Bluetooth Address. It is 64:bc:0c:xx:xx:xx (Note: I have blanked out the last three device-specific bytes of the MAC, revealing only the first three bytes which is the Company OUI assigned to LG Electronics, the manufacturer of the Nexus 5X.)

对于此测试，我在配置了BlueZ的Linux设备上启动了蓝牙LE扫描.扫描输出找到的每个新BLE设备的MAC地址. BlueZ不会对这个MAC地址进行加密.

For this test, I start a bluetooth LE scan on a Linux device configured with BlueZ. The scan outputs the MAC address of each new BLE device it finds. BlueZ does not scramble this MAC address.

接下来，我反复启动和停止Nexus 5X上的发射器.每次执行此操作时，扫描结果中都会显示一个新的MAC地址.在下面的输出中，我每次按下返回键几次，在每次检测后都显示空白行，以显示关闭并重新打开发射机的时间.

Next, I repeatedly start and stop the transmitter on the Nexus 5X. Each time I do a new MAC address shows up in the scan results. In the output below, I hit the return key a couple of times to make blank lines after each detection to show when I turn the transmitter off and back on.

$ sudo hcitool lescan
LE Scan ...


5C:62:56:18:DA:A5 (unknown)
5C:62:56:18:DA:A5 (unknown)


6A:E8:D1:90:CA:26 (unknown)
6A:E8:D1:90:CA:26 (unknown)


70:A8:86:F7:E9:68 (unknown)
70:A8:86:F7:E9:68 (unknown)


66:F6:B4:24:89:44 (unknown)
66:F6:B4:24:89:44 (unknown)

如您所见，发射机每次启动时，都会发送一个新的随机MAC地址，该地址与设置"报告的物理MAC地址无关.

As you can see, each time the transmitter is started, it send out a new randomized MAC address that has nothing to do with the physical MAC address reported by Settings.

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