NetworkDebugging

Network noise

When testing on a typical Linux host, there can be a lot of background network traffic generated by daemons like Samba or Avahi. To avoid their influence, it's recommended to stop them:

# Ubuntu
service samba stop (old Ubuntu)
service smbd stop
service nmbd stop

# because otherwise systemd will socket-activate it at once again
systemctl disable avahi-daemon
service avahi-daemon stop

Network shell

For non-interactive apps, it makes sense to enable CONFIG_NET_SHELL, then shell can be used in parallel with the main app functioning:

shell> select net  
net> help
...
net> iface
...
net> mem
Fragment length 128 bytes
Network buffer pools:
Address		Count	Name
0x0041b2f4	4	RX
0x0041b310	2	TX
0x0041b38c	16	RX DATA
0x0041b3ac	16	TX DATA

Packet buffers architecture

net_pkt's live in memory slabs (fixed-size-alloc memory containers), separately for RX and TX packets. net_buf's live in memory pools (var-size-alloc memory containers), also separately for RX and TX (shown as RX DATA and TX DATA) above.