CCS/CC2652R: How to change MPS (max payload size) in L2CAP Connection Oriented Channels

Hi,

I have assigned an expert to comment on this.

Best Regards,
Alec

Hi Krs,

Which SDK are you working off of? If you are referring to the maximum size of any packet transmitted between a client and server (ATT_MAX_MTU_SIZE), you can modify this value in the file source\ti\ble5stack\inc\att.h.

Best Regards,

Jenny

I am using simplelink_cc13x2_26x2_sdk_4_30_00_54 sdk.

Regarding the MPS value I want to change.... I am not sure what I have to change. From the documentation found here I assume it is the size of the LE Packet (27 bytes by default). which is set by MAX_PDU_SIZE.

There is also ATT_MAX_MTU_SIZE, where does this come into play? How can this be independent of MAX_PDU_SIZE?

So in the end... MSP == MAX_PDU_SIZE?

Edit: Rephrased the question.

When encountering this SDU, PDU, MTU, MSP, ATT_MTU for the first time, a clear graphical explanation would be of much help to understand all terms.

In your first link, the graphical explanation of fragmentation is misleading .(Figure 94. L2CAP Packet Fragmentation.)

Fist it refers to ATT_MTU which is emphasized above as a different thing.

Secondly it does not detail the structure of individual LE packets.

And it does not detail that the first le packet will have SDU length inside the payload.

Here I found a slightly better explanation of LE Packets, but even that has its own flows.

Hi Krs,

I agree with you a clear graphical representation within the section these terms are mentioned will better aid in explaining these terms. We will take this input into account when working on the documentation. Thanks!

Best Regards,

Jenny