Re: direwolf frame size #direwolf #ax25


jgindc1@...
 

John, WB2OSZ,

I am using a pre-installed/configured version of direwolf that is included with the Raspberry Pi image. I use a provided shell script to start and stop direwolf. 

 In order to run direwolf with your suggested arguments, I have to invoke the ax25-stop script to stop the current direwolf instance. I then run direwolf with your suggested arguments which appears to be successful.

Unfortunately, my email client application (PAT) reports that "No AX25 ports configured" and therefore I am unable to attempt to send the large message. I do not know if there is a way to change the PAT configuration to help with this issue.

I plan to post to the PAT group as Basil suggested.

Thanks for your suggestions,

John KM7LJ

On Mon, Feb 25, 2019 at 6:35 PM WB2OSZ <wb2osz@...> wrote:
There are two different ways that applications can use direwolf as a TNC.

(1) As a stupid KISS TNC.  In this case the application is totally in control.  The stupid TNC just does what it is told.  Decisions about PACLEN, MAXFRAME, etc. are made entirely by the application layer.  (Or AX.25 for Linux if that is in the middle.)

(2) The AGW network interface allows direwolf to perform the link layer (connected mode) function.  In this case the direwolf configuration has the usual PACLEN, MAXFRAME, etc.

This block diagram illustrates how the AGW network interface can access more functionality inside the TNC.   https://github.com/wb2osz/direwolf/blob/master/direwolf-block-diagram.png   It is advantageous to use that interface if your application supports it. 

This application note  https://github.com/wb2osz/direwolf/raw/dev/doc/Why-is-9600-only-twice-as-fast-as-1200.pdf  explains the differences between using the AX.25 link layer built in to direwolf or having the application treat it as a stupid KISS TNC.

Back to your question.  We need to run a test to see what is going on.  Run direwolf with these options:

direwolf -d nao -T %T  2>&1 | tee w.log

This will capture information about the conversation between your application and direwolf.  It will also print information about Carrier Detect and PTT so we can see how many frames are in each transmission.  The -T option will add timestamps.   Finally it is all captured in a file so we can examine it later.

Join udrc@nw-digital-radio.groups.io to automatically receive all group messages.