When using a wireless link for point-to-point or mesh applications, especially with tunnels or L2 protocols (B.A.T.M.A.N., for example), being able to use more than the "standard" MTU of 1500 has great value.
Even if bridged (and there is no reason for a bridge in these applications), the underlying MTU of the wireless link itself will put an upper bound on the bridge MTU.
However, I don't seem to be able to set the MTU using /etc/config/network
directly. I've tried
/etc/config/wireless
stanza:
config wifi-iface 'mesh1'
option device 'radio5'
option ifname 'mesh1'
option mode 'mesh'
option mesh_id '<redacted>'
option mesh_fwding '0'
option encryption 'psk2+ccmp'
option key '<redacted>'
/etc/config/network
stanza:
config interface 'mesh1'
option ifname 'mesh1'
option mtu '2304'
option proto 'static'
but the MTU doesn't show as 2304
(There is no need for an address on this interface, and configuration of routes is easier if there is not.)
21: mesh1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DORMANT group default qlen 1000
link/ether <redacted> brd ff:ff:ff:ff:ff:ff
In the past I've "hooked" the netifd
scripts to manage this directly
if [ "$ifname" = "mesh0" ] ; then
ip link set dev mesh0 mtu 2304
fi
Is there a way that I can simplify my configuration and build by managing the MTU directly through /etc/config/network
?