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. Major distraction is also the Chrome browser which stealthly spams network using UPNP.

# 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.