Hi, Stephen Follow your advice, I made a new patch. This patch will turn off carrier when a new bridge interface is created. Please comment on it. Thanks a lot. Zhu Yanjun On 02/14/2015 02:30 AM, Stephen Hemminger wrote: > On Fri, 13 Feb 2015 17:57:45 +0800 > yzhu1 wrote: > >> Hi, all >> >> I made this test on ubuntu 14.04 with kernel 3,19-rc7: >> >> 1. brctl addbr br0 >> >> 2. ifconfig br0 up >> >> 3. ifconfig br0 (br0's status is with 'RUNNING') >> >> 4. brctl addif br0 eth0 >> >> 5. brctl delif br0 eth0 >> >> 6. ifconfig br0 (br0's status is without 'RUNNING') >> >> When there is no sub-interface, the flag "RUNNING" is missing after the >> last sub-interface is removed. >> >> As such, should we keep "RUNNING" flag after the last sub-interface is >> removed? > This is intentional. If there are no active ports in bridge, then > we want to tell applications that packets will go nowhere. > >