Re: NetworkManager auto connect/auto switch policy

[Dan Williams <dcbw redhat com>]

On Wed, 2009-03-04 at 21:29 +0800, 代尔欣 wrote:
> Hi Dan,
>    Can you please give me a conceptual description about what is the
> policy of auto connect/switch when more than one network available
> e.g. ethernet wifi(may several)?

All available connections are brought up.  For ethernet, that usually
means when the card indicates it has a carrier.  For wifi, that means
that the card is not rfkilled, and at least one saved AP has been found
in the wifi scan list.  NM will also not automatically activate any
connection where autoconnect has been turned off.

The default route determines where the traffic actually goes; when a
"better" connection becomes available, NM will switch the default route
to that new connection in one operation, thus the switch is only done
when everything is set up.  When a that "better" connection goes away,
NM will switch the default route to the next-best connection, if any.

The preference order for "better" connections is Ethernet > Wifi > 3G.

Dan