android - Wi-Fi Direct 和 "normal"Wi-Fi - 不同的 MAC？

Question

我目前正在尝试通过 Wi-Fi Direct 连接两部知道彼此 MAC 地址的手机，但偶然发现了以下问题: 我从

收到的 MAC 地址

    WifiManager wifiMan = (WifiManager) this
            .getSystemService(Context.WIFI_SERVICE);
    WifiInfo wifiInf = wifiMan.getConnectionInfo();
    MAC_ADDRESS = wifiInf.getMacAddress();

与我在发现和请求对等点时从 WifiP2pManager 收到的略有不同。示例:a0:xx:xx:... 变为 a2:xx:xx.... 有谁知道为什么？我没有找到任何方法来获取“Wi-Fi Direct MAC 地址”，而且我认为 MAC 地址应该是唯一的，并且它是处理两者(普通 Wi-Fi 和 P2P/Direct)的同一个 Wi-Fi 模块.这很奇怪.. 我应该怎么办？对于我得到的两个设备 (Galaxy Nexus)，MAC 地址总是只有前两个字符不同——我应该简单地丢弃它们吗？遇到问题(两台设备仅 MAC 地址第一部分不同)的概率是否太高？

谢谢。

Answer 1

阅读 MAC address在维基百科上。

Addresses can either be universally administered addresses or locally administered addresses.

Universally administered and locally administered addresses are distinguished by setting the second-least-significant bit of the most significant byte of the address. This bit is also referred to as the U/L bit, short for Universal/Local, which identifies how the address is administered. If the bit is 0, the address is universally administered. If it is 1, the address is locally administered.

由于 Wi-Fi Direct 只是 MAC 之上的另一个堆栈，您还应该检查该位对它的含义。我找到了一些 mail discussion阐明这一点。显然下面的引用来自 WFA 规范。

The P2P Device shall assign a P2P Interface Address, corresponding to the format as described in §7.1.3.3.1 of IEEE Std 802.11‑2007 1, which is used to communicate with the P2P Group Owner or Clients within a P2P Group. A P2P Interface Address is not required to be globally unique and may be locally administered. A P2P Interface Address may be the same as the P2P Device Address provided the requirements for P2P Interface Address in this clause are satisfied.

所以我认为这个问题的答案是，您不应该从 WifiManager 获取 MAC 地址并将其用于 Wi-Fi P2P 连接。