UDP packet has extra bytes

[manitou]

Using version AT version:0.21.0.0 SDK version:0.9.5, if i use UDP to send less than 18 bytes, the packet sent by ESP8266 has extra bytes on the end. The IP and UDP packet length fields are correct and do not refect the extra bytes. here is tcpdump at linux receiver site, when sending 8 bytes (the ESP is IP address 192.168.1.137). Receiver just echoes back what it receives.

Code: Select all

19:24:15.180129 IP 192.168.1.137.4321 > manitou.7654: UDP, length 8
    0x0000:  4500 0024 00ca 0000 ff11 3721 c0a8 0189
    0x0010:  c0a8 0104 10e1 1de6 0010 7c54 3132 3334
    0x0020:  3536 3738 0000 0000 0000 4b05 ee98
19:24:17.121749 IP manitou.7654 > 192.168.1.137.4321: UDP, length 8
    0x0000:  4500 0024 8de6 4000 4011 2905 c0a8 0104
    0x0010:  c0a8 0189 1de6 10e1 0010 83ff 3132 3334
    0x0020:  3536 3738



[ESP_Faye]

Hi,

This is normal , not a bug.

MAC layer has a minimum length limitation，so it will add extra bytes. It is a part of protocol.

We will distinguish what is the actual useful data, and get the correct data length.

Thanks for your interest in ESP8266 !