Comment 9 for bug 802782

I'm seeing this on a fleet of laptops which all have Fast Ethernet, 802.11a/g/n and GSM HSPA interfaces.

If the WLAN is active and configured as the default route when the GSM HSPA WWAN is activated the default route is changed to be the WWAN.

I wonder if NM could accept a user-specified (or automatically assigned) metric for each interface without requiring a static route to be specified?

If the user then chooses to disconnect from an existing network or the connection drops through being out of range the next most senior link would be selected. The manual configuration I use for default routes is:

$ ip route ls
default via 10.254.251.1 dev eth0 proto static metric 1
default via 10.254.251.1 dev wlan0 proto static metric 9
default via 10.50.163.2 dev wwan0 proto static metric 19
10.0.3.0/24 dev lxcbr0 proto kernel scope link src 10.0.3.1
10.50.163.0/26 dev wwan0 proto kernel scope link src 10.50.163.32 metric 7
10.254.1.0/24 dev virbr0 proto kernel scope link src 10.254.1.1
10.254.251.0/24 dev eth0 proto kernel scope link src 10.254.251.50 metric 1
10.254.251.0/24 dev wlan0 proto kernel scope link src 10.254.251.60 metric 9

Notice how the metric assigned by NM to wwan0's link (7) is more senior than wlan0 (9). I think that could do with changing as a default so that 802.11a/g takes preference behind wired Ethernet.