more explanation for network.mode file

Signed-off-by: Tobias Klaus <tk+ff@meskal.net>
Reviewed-by: Christian Dresel <fff@chrisi01.de>
Reviewed-by: Tim Niemeyer <tim@tn-x.org>

bsp/ar71xx/root_file_system/etc/network.mode

@@ -1,18 +1,30 @@
-#what should the one eth0 ethernet port be used for?
-#directly connect to other mesh nodes - this is the default
-ETHMODE="BATMAN"
-
-#Connect with fastd vpn
-#ETHMODE="WAN"
-
-#connect normal ff-clients
-#ETHMODE="CLIENT"
-
 ################
-## If you want to change the behavior of eth0, you can change it above.
+## This file is used to configure the behavior of network interfaces
+## if the routers interfaces differ from the standard WAN+4LAN-Ports
+## +2Wireless APs.
+## If you want to change their behavior, you can do so below.
 ## After that you have to reset the config with following commands.
 #cp /rom/etc/sysctl.conf /etc/sysctl.conf
 #cp /rom/etc/config/network /etc/config/network
 #reboot
-################
-
+#
+### The canonical syntax of this file is:
+#SPECIFIER="MODE"
+### MODES
+## Generally there are 3 operating modes for network interfaces in fff.
+#BATMAN: The interface is used to mesh with other fff-nodes
+#WAN:    The interface is used to connect to supernodes via vpn and
+#         ordinary internet.
+#CLIENT: The interface is used to connect clients to the fff-net
+##
+### SPECIFIER
+## For devices only including one ethernet port the specifier is called
+## ETHMODE. The default mode for these devices is "BATMAN".
+## For example this is the case for: gl-ar150, tl-mr3020-v1, tl-wa850re-v1,
+## tl-wa860re-v1, ubnt-bullet-m, ubnt-loco-m-xw, ubnt-nano-m
+ETHMODE="BATMAN"
+## Devices featuring 2 ethernet ports are configured by SPECIFIERs ressembling
+## the labels on the PORT itself. For the cpe210 these are called LAN0 and LAN1.
+## Therefore they are configured as follows:
+LAN0MODE="WAN"
+LAN1MODE="BATMAN"