I have two computers that have a direct ethernet wire between them. The interface is set to a static ip address on each side, and under control of the NetworkManager.

About 1/10 the time the interface does not start. The messages log file will show:

Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): carrier is OFF
Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): new Ethernet device (driver: 'r8169' ifindex: 2)
Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): exported as /org/freedesktop/NetworkManager/Devices/0
Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): now managed
Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): device state change: unmanaged -> unavailable (reason 'managed') [10 20 2]
Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): bringing up device.
Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): preparing device.
Jun 22 13:01:22 owl10 NetworkManager[601]: <info> (p6p1): deactivating device (reason: 2).
Jun 22 13:01:22 owl10 kernel: [ 4.932240] r8169 0000:05:00.0: p6p1: link down
Jun 22 13:01:22 owl10 kernel: [ 4.932248] r8169 0000:05:00.0: p6p1: link down
Jun 22 13:01:22 owl10 kernel: [ 4.932634] ADDRCONF(NETDEV_UP): p6p1: link is not ready


And, if I just physically unplug the cable and plug it back in NetworkManager starts the interface:

Jun 22 13:08:40 owl10 kernel: [ 442.658355] r8169 0000:05:00.0: p6p1: link up
Jun 22 13:08:40 owl10 kernel: [ 442.658875] ADDRCONF(NETDEV_CHANGE): p6p1: link becomes ready
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> (p6p1): carrier now ON (device state 20)
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> (p6p1): device state change: unavailable -> disconnected (reason 'carrier-changed') [20 30 40]
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) starting connection 'Middle Port'
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> (p6p1): device state change: disconnected -> prepare (reason 'none') [30 40 0]
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 1 of 5 (Device Prepare) scheduled...
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 1 of 5 (Device Prepare) started...
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 2 of 5 (Device Configure) scheduled...
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 1 of 5 (Device Prepare) complete.
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 2 of 5 (Device Configure) starting...
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> (p6p1): device state change: prepare -> config (reason 'none') [40 50 0]
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 2 of 5 (Device Configure) successful.
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 3 of 5 (IP Configure Start) scheduled.
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 2 of 5 (Device Configure) complete.
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 3 of 5 (IP Configure Start) started...
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> (p6p1): device state change: config -> ip-config (reason 'none') [50 70 0]
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 4 of 5 (IP4 Configure Get) scheduled...
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 3 of 5 (IP Configure Start) complete.
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 4 of 5 (IP4 Configure Get) started...
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 5 of 5 (IP Configure Commit) scheduled...
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 4 of 5 (IP4 Configure Get) complete.
Jun 22 13:08:40 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 5 of 5 (IP Configure Commit) started...
Jun 22 13:08:40 owl10 avahi-daemon[614]: Joining mDNS multicast group on interface p6p1.IPv4 with address 192.168.3.10.
Jun 22 13:08:40 owl10 avahi-daemon[614]: New relevant interface p6p1.IPv4 for mDNS.
Jun 22 13:08:40 owl10 avahi-daemon[614]: Registering new address record for 192.168.3.10 on p6p1.IPv4.
Jun 22 13:08:41 owl10 NetworkManager[601]: <info> Policy set 'Side Port' (p7p1) as default for IPv4 routing and DNS.
Jun 22 13:08:41 owl10 NetworkManager[601]: <info> (p6p1): device state change: ip-config -> activated (reason 'none') [70 100 0]
Jun 22 13:08:41 owl10 NetworkManager[601]: <info> Activation (p6p1) successful, device activated.
Jun 22 13:08:41 owl10 NetworkManager[601]: <info> Activation (p6p1) Stage 5 of 5 (IP Configure Commit) complete.


So, I imagine there is a race condition where both boxes wait for the other to start the interface.

My question: Is there anyway to force NetworkManager to bring up an interface even if there is no Carrier?

BTW, this problem started recently on Fedora 13 after some upgrades. We upgraded to the latest Fedora 15 to try and solve it, and it now appears more often than it did on Fedora 13.

Doug

I get the feeling it is a hardware issue. Bad cable or connectors or nic's.

What happens when you use ifconfig up or ifup or whatever is in that distro?

Looks like the new way to name is working but I'd check that.

Seems there are many issue with this release. N

I moved the discussion to the NetworkManager developers mailing list.