PacketQueue implementation in Ieee802154Mac module

[n-jay]

Hello everyone,
I am currently working on implementing memory buffers in nodes that use the Ieee802154NarrowbandInterface, which utilizes the Ieee802154Mac module. I am using INET 4.2.5, so the naming conventions might differ from the latest version.

I have been experimenting with the PacketQueue simple module that is implemented within Ieee802154Mac, and I need clarification on the following:

1. whether the PacketQueue module acts as a buffer for transmissions, receptions, or both. Just observing the packet flow using the Qtenv GUI and it seems like both.
2. If only transmissions, do we have to add another queue as a submodule to collect receiving signals?
3. When the packetPushed statistic is checked it is significantly less than the number of packets that have been registered by a module in the network work. Does that mean not all packets received at a node is getting registered in the queue?

[n-jay]

@rhornig would appreciate some thoughts on this. 😄

[rhornig]

Sadly, this is above may pay grade :) @levy perhaps?

[levy]

The PacketQueue module is just a queue for packets, so in itself it's neither for transmitted or received packets. In network interface modules, the queue submodule, that is a PacketQueue module by default, is used to store outgoing packets. In other words the queue module stores packets that will be transmitted. Please note that there are as many PacketQueue modules as there are network interfaces in the network. This may be the answer for your third question.

[n-jay]

Noted @levy, thanks!
In relation to Q2, do we have to add another queue as a submodule (within Ieee802154Mac module) to store receiving packets? or can the existing queue be modified to accept receiving packets also?