Packet Size of Reply Packet about lorawan

[DvdMgr]

If you want a fixed packet size, you can directly change the code in EndDeviceStatus::GetCompleteReplyPacket to create a packet with a set payload size!

[Prapi123]

Hello @DvdMgr

I have been modifying EndDeviceStatus.cc file for my convenience and I am facing some issue in it.

1. I have used a code to modify replypaylaod size as given below

 for (NodeContainer::Iterator j = endDevices.Begin ();
       j != endDevices.End (); ++j)
  {
    Ptr<Node> node = *j;
    uint32_t senderID = node->GetId ();
    std::cout << "senderID: " << senderID << std::endl;
    Ptr<LoraNetDevice> loraNetDevice = node->GetDevice(0)->GetObject<LoraNetDevice> ();
    Ptr<LoraPhy> phy = loraNetDevice->GetPhy ();

    Ptr<LoraMac> mac = loraNetDevice->GetMac ();
    Ptr<EndDeviceLoraMac> edLoraMac = mac->GetObject<EndDeviceLoraMac> ();
    LoraDeviceAddress Address = edLoraMac->GetDeviceAddress();
    Ptr<EndDeviceStatus> edStatusP3 = CreateObject<EndDeviceStatus> (Address, edLoraMac);

    Ptr <Packet> replypayload = Create<Packet> (126);
    edStatusP3->SetReplyPayload (replypayload);

    LoraFrameHeader d = edStatusP3->GetReplyFrameHeader();
    std::cout<< d << std::endl;
  }

Above I am changing the attaching the payload with Setreplypayload() but still I can see output as below

It is creating an empty packet instead of creating a packet with size I have already stated.

My idea is to emulate handshake between NS and end device and so I want to create reply packet according to the size of uplink packet.
for example if uplink packet size is 30 byte then downlink packet should be 23
if uplink packet size is 50 byte then downlink packet should be 15

Thanks and Regards
@Prapi123

[DvdMgr]

In that case, you have two ways to go about it:

1. Undo your changes to end-device-status.cc, and create a new NetworkControllerComponent object - this will need to implement a BeforeSendingReply method, which is a callback called by the NetworkController before sending a reply, and is where you will have the chance to modify the EndDeviceStatus's reply payload by calling the SetReplyPayload method. You can use the components defined in network-controller-components.cc file to draw some inspiration about the structure and functionality. Don't forget to add it to the InstallComponents method of the NetworkServerHelper to activate it!
2. Define all the needed logic directly inside the GetCompleteReplyPacket method: you can remove the if/else that either uses the m_reply.payload or creates a new packet from scratch, and make it so that it always creates a packet with the needed size. If you want to always send a packet with a payload of 50, for instance, you simply use replyPacket = Create<Packet> (50);.

The code you mentioned above does not work because you are creating new EndDeviceStatus objects, instead of acting upon the ones that already exist and are used in the simulation!

[Prapi123]

Hello,

Thanks for responding to this issue.
I could emulate TLS handshake with above recommended process.

I am trying to solve minor error, I want to create a packet replyPacket = Create (1200);
if gives an error "large integer implicitly truncated to unsigned type [-Woverflow] "

I suppose this is due to range of Unsigned integer which is 0-255 so tried to change data-type in source file. Still no luck.

[DvdMgr]

Keep in mind that the maximum size for the payload of a LoRaWAN packet is from 50 to 200 bytes, depending on the spreading factor! Sending packets 1200 bytes long just is not possible with this technology

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On Thu, Dec 19, 2019, 9:04 PM Prapi123 ***@***.***> wrote: Hello, Thanks for responding to this issue. I could emulate TLS handshake with above recommended process. I am trying to solve minor error, I want to create a packet replyPacket = Create (1200); if gives an error "large integer implicitly truncated to unsigned type [-Woverflow] " I suppose this is due to range of Unsigned integer which is 0-255 so tried to change data-type in source file. Still no luck. — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#61?email_source=notifications&email_token=AATSICPANHPO2S2KEEH2OEDQZPHUZA5CNFSM4JYJOSPKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEHKYQMY#issuecomment-567642163>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AATSICLDXOGNWJCBULNDM63QZPHUZANCNFSM4JYJOSPA> .