CC1310: About the mac retransmiting of sub1G.

dennis yang

Intellectual 945 points

Part Number: CC1310

Hi TI friends:

In simplelink example of 802.15.4.

I can see TI enabled mac retransmiting by setting dataReq.txOptions.ack = true.

And it seems PIB ApiMac_attribute_maxFrameRetries is the max counts of mac retransmitting and the default value is 3.

Sometimes we can see from collector side that one data package was received for 2 or even 3 times.

I doubt it was because sensor failed to get ack and retransmit data package again so collector received the same data package more than one time.

But why mac don't filter this repeated data packages?

Hoping for your response soon.

Thanks.

over 7 years ago

0 dennis yang over 7 years ago

Intellectual 945 points

Hi TI friends:
Can help to pay attention to this issue?

Thanks.

0 YiKai Chen over 7 years ago in reply to dennis yang

Guru 735685 points

Try to revise maxFrameRetries of macPibDefaults in hmac_global.c

0 dennis yang over 7 years ago in reply to YiKai Chen

Intellectual 945 points

Hi Yikai:

Thanks for your reply.

We have found ways to modify maxFrameRetries.

But we need to find out how to filter the same data package rereceived because of ack not received by sensor.

0 YiKai Chen over 7 years ago in reply to dennis yang

Guru 735685 points

If I am correct, the same data packets would be filter by Stack itself and application doesn't have to do this.

0 dennis yang over 7 years ago in reply to YiKai Chen

Intellectual 945 points

Hi Yikai:
I agree with you but what I see is that same packages reported to APP is not filtered.

Thanks.

0 Hector_r over 7 years ago in reply to dennis yang

TI__Genius 12415 points

Hi,

The reason why these packets are not filtered out is because every re-transmission has a different sequence number which makes them seem like a new packet to the stack.
To get around this, you should append your own application specific sequence number to your application messages which will not change in a re-transmission therefore making it possible for you to filter these repeated messages in your applications.

Regards,
Hector

0 dennis yang over 7 years ago in reply to Hector_r

Intellectual 945 points

Hi Hector:

I have caught pcap log to see this issue.

And it shows the retrans use the same sequence number.

which is different to what your said.

0 Hector_r over 7 years ago in reply to dennis yang

TI__Genius 12415 points

I see, let me run some tests and I'll let you you what I find.

Thanks,
Hector

0 Hector_r over 7 years ago in reply to dennis yang

TI__Genius 12415 points

Hi,

I believe the reason why these messages are not getting filtered out is because you don't have security enabled. So in this case you will have to filter the packets out at the application layer.

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CC1310: About the mac retransmiting of sub1G.