blocking tcp client socket has problem, in wifi auto reconnection

amanaganti vinod kumar1

Other Parts Discussed in Thread: CC3200

Hi All,

I am using cc3200 in my project with power management framework, I used tcp sockets for cloud application thread. This thread will connect to cloud server and communicate over this blocking socket.

Cloud thread is waiting for packets from cloud-server using sl_recvfrom() call in a while loop, when it receives a packet it will process it and sends the response back.

There is a problem in socket usage, When wifi is disconnected and reconnected to same or different AP.

Cloud thread is not coming out of sl_recvfrom() on wifi-disconnected event, I tried to close the socket on wifi-connection event it is throwing SL_INEXE (socket command execution) error.

Due to these issues, I am not able to use the socket and thread is completely stuck on sl_recvfrom() call..

Is this implicit problem with SDK1.0.0, any work around is there to handle issues like this?

your support is appreciated in advance.

over 10 years ago

0 Raghavendra Shenoy over 10 years ago

TI__Mastermind 27095 points

Hi,

We will check this and get back to you.

Regards,
Raghavendra

0 Raghavendra Shenoy over 10 years ago in reply to Raghavendra Shenoy

TI__Mastermind 27095 points

Hi VinodKumar,

This is the expected behavior. The sl_RecvFrom function call will not return until the time-out occurs. Even if the WLAN disconnects, the sl_RecvFrom would be in execution. Therefore, you would get SL_INEXE while closing this socket.

1. You can try reducing the socket time-out for sl_RecvFrom or sl_Select.
2. You can use non-blocking sockets for this use-case.

Regards,
Raghavendra

0 amanaganti vinod kumar1 over 10 years ago in reply to Raghavendra Shenoy

Intellectual 650 points

Hi Raghavendra,

Thanks for your reply.

We are using power management feature in our product, LPDS mode has issues with socket timeout, due to this obstacle we had to use blocking mode sockets.

How to make use of LPDS and blocking sockets, in wifi auto-reconnection.

Could you provide any alternate method, that can solve this issue.

0 Raghavendra Shenoy over 10 years ago in reply to amanaganti vinod kumar1

TI__Mastermind 27095 points

Hi Vinod Kumar,

Can you please explain the use-case a bit more? What issues are you facing with LPDS while setting a time out?

Regards,
Raghavendra

0 amanaganti vinod kumar1 over 10 years ago in reply to Raghavendra Shenoy

Intellectual 650 points

Hi Raghavendra,

Our project is an IP-CAMERA, where we are using DMVA2, CC3200 and cloud support is provided.

DMVA2 will send video packets through raw sockets of cc3200. Whenever there is no streaming request from user cc3200 will turn off the dmva and goes to LPDS Mode.

CC3200 will wake up from LPDS based on any stream request from cloud, or sensor triggers or 5mins timeout. This 5 mins timer is used to post a keep alive message to cloud.

On any stream request we will switch the cloud processing, from cc3200 to DMVA2. by sending close tcp socket command to cloud, and opening raw socket. Now DMVA2 will communicate with cloud over cc3200 raw socket.

If we use timeout based tcp socket, Device will come out from LPDS mode for every socket timeout. which shouldn't happen in our case to avoid power consumption.

Is there any solution for this use case, where we have to use blocking tcp socket, LPDS and wifi auto reconnection all together, problem is happening only on device disconnected from AP and connected to another ap as I mentioned in the beginning..

0 Raghavendra Shenoy over 10 years ago in reply to amanaganti vinod kumar1

TI__Mastermind 27095 points

Hi,

Did you try your scenario with sl_Select? There is a similar topic discussed in this thread: e2e.ti.com/.../1469402

Please let me know if this helps.

Regards,
Raghavendra

0 amanaganti vinod kumar1 over 10 years ago in reply to Raghavendra Shenoy

Intellectual 650 points

Hi Raghav,

Sorry for the delay replying, I was stuck in some other issues.

sl_select timeout is making the controller to wakeup from the LPDS mode, So we are not able use sl_select cal.

Could you please provide any other solution to this thread.

0 Alon Srednizki over 10 years ago in reply to amanaganti vinod kumar1

TI__Mastermind 18455 points

Hi,

sl_select can be used with an infinity timeout (by setting NULL) and shouldn't wake up the host processor.
This should solve your issue, since if disconnecting, you will be able to close the socket.

Thanks,
Alon

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blocking tcp client socket has problem, in wifi auto reconnection