Linux-Hams archive - October 1997: some questions about 'listen'

some questions about 'listen'

Pete Rossi WA3NNA (terhi.victor@logonet.com)
Wed, 1 Oct 1997 22:29:34 -0400


Questions or two about the 'listen' utility.

I find it hard to correlate what 'listen' displays and what goes out
over the air. I was under the impression that listen displayed
each packet heard or transmitted, however, I consistently see multiple
outgoing packets displayed yet I only "hear" one packet go out over
the radio.

For example... during a telnet session, I typed "ls" and listen displayed...

> [Wed Oct 1 22:10:15 1997]
> Port radio: AX25: WA3NNA-8->W3BG-8 <UI> pid=IP
> IP: len 41 44.80.12.133->44.80.12.28 ihl 20 ttl 64 DF prot TCP
> TCP: 12195->telnet Seq x7d637246 Ack x93388d9c ACK PSH Wnd 31744 Data 1
> 0000 6C | l
>
> [Wed Oct 1 22:10:17 1997]
> Port radio: AX25: WA3NNA-8->W3BG-8 <UI> pid=IP
> IP: len 41 44.80.12.133->44.80.12.28 ihl 20 ttl 64 DF prot TCP
> TCP: 12195->telnet Seq x7d637246 Ack x93388d9c ACK PSH Wnd 31744 Data 1
> 0000 6C | l
>
> [Wed Oct 1 22:10:32 1997]
> Port radio: AX25: WA3NNA-8->W3BG-8 <UI> pid=IP
> IP: len 41 44.80.12.133->44.80.12.28 ihl 20 ttl 64 DF prot TCP
> TCP: 12195->telnet Seq x7d637246 Ack x93388d9c ACK PSH Wnd 31744 Data 1
> 0000 6C | l

Yet, I actually HEARD my radio transmit only *one* packet. So.. what
really happened? and what is 'listen' trying to tell me? Was one packet
transmitted, 3 packets transmitted in one burst, or is "listen" confused?

Also there seems to often be considerable delay between either hearing
a packet and having 'listen' display it... or seeing outgoing packets
displayed and hearing my radio transmit them.

Sure can make it tricky trying to follow exactly what is going on.

Can someone explain what exactly is 'listen' displaying?

BTW, I normally use 'listen -t -a -h'

---

Pete Rossi - WA3NNA kbsrzpdg.ooeonzey@relay.tunkki.fi