MQTT : AT+QMTCONN gives result = 1 Packet retransmission

IoT Modules LTE Standard Module
1

Hi ,
I am using EC/EG 25 module for the MQTT connection.

AT+QMTCONN=<client_idx>,“< clientid >”[,“< username >”,"< password> "]

Above command gives result code as 1 (Packet retransmission)

query :

  1. What is the meaning of Packet retransmission ?
  2. How to handle this from host controller ? Do we need to wait and check some commands ?
2

Hi @lyman-Q
Could you please help on above query related to MQTT ?

3

Please provide your log

4

Hi ,
I dont have the AT log now as above observed while doing testing AT commands .

But here my following query is to understand how to handle this response in code ?

  1. What is the meaning of Packet retransmission ?
  2. How to handle this from host controller ? Do we need to wait and check some commands ?

image
image1582×820 64.4 KB

5

Packet retransmission indicates that the retransmission mechanism has been triggered in the protocol stack of the module, but the data is still not successfully sent by the air

6

Thanks @herbert.pan-Q for you reply .
But my question is that how we should handle this reply ? do we need to wait ? or canccel the current connection and try again ? or something else ?

7

I suggest first disconnecting and re-connecting; If it still fails, you need to reboot the module

8

Ok
Thanks

We will implement the logic similar to what you proposed

9

I am having the same issue, I am using a Quectel EC200U-CN 4G LTE module to connect to MQTT broker but as I try to send a CONN req to the broker using AT+QMTCONN=0,“akshat”,“”,“”. I get 2 errors

+QMTCONN: 0,1 ( ClientIdx, Packet Retransmmiting )

+QMTSTAT: 0,3 (ClientIdx, Sending Connect Packet Timed out)

Can you please help me with this issue, I am attaching my log files as well.

Quectel log
Quectel log397×531 11.5 KB

10

you need run,such as

AT+QMTCONN=0,“client_test”