[CentOS] Network broke for a while when libvirtd start

Sat Feb 24 05:41:33 UTC 2018
wuzhouhui <wuzhouhui14 at mails.ucas.ac.cn>

When start service libvirtd by

    service libvirtd start

the network will broke for a while and then reconnected. Following is /var/log/messages:

Feb 24 13:28:51 node-0 kernel: lo: Dropping TSO features since no CSUM feature.
Feb 24 13:28:51 node-0 kernel: lo: Disabled Privacy Extensions
Feb 24 13:28:51 node-0 kernel: virbr0: Dropping TSO features since no CSUM feature.
Feb 24 13:28:51 node-0 kernel: virbr0: Dropping TSO6 features since no CSUM feature.
Feb 24 13:28:51 node-0 kernel: device virbr0-nic entered promiscuous mode
Feb 24 13:28:51 node-0 kernel: virbr0: starting userspace STP failed, starting kernel STP
Feb 24 13:28:51 node-0 kernel: ip_tables: (C) 2000-2006 Netfilter Core Team
Feb 24 13:28:51 node-0 kernel: nf_conntrack version 0.5.0 (16384 buckets, 65536 max)
Feb 24 13:28:51 node-0 kernel: virbr0: topology change detected, propagating
Feb 24 13:28:51 node-0 kernel: virbr0: port 1(virbr0-nic) entering forwarding state
Feb 24 13:28:51 node-0 kernel: 8021q: adding VLAN 0 to HW filter on device virbr0
Feb 24 13:28:51 node-0 kernel: ixgbe 0000:02:00.0: eth2: detected SFP+: 3
Feb 24 13:28:52 node-0 kernel: ixgbe 0000:02:00.1: eth3: detected SFP+: 4
Feb 24 13:28:52 node-0 kernel: bonding: bond0: link status definitely down for interface eth2, disabling it
Feb 24 13:28:52 node-0 kernel: virbr0: port 1(virbr0-nic) entering disabled state
Feb 24 13:28:52 node-0 kernel: bonding: bond0: link status definitely down for interface eth3, disabling it
Feb 24 13:28:53 node-0 kernel: ixgbe 0000:02:00.0: eth2: NIC Link is Up 10 Gbps, Flow Control: RX/TX
Feb 24 13:28:53 node-0 kernel: bond0: link status definitely up for interface eth2, 10000 Mbps full duplex.
Feb 24 13:28:53 node-0 kernel: ixgbe 0000:02:00.1: eth3: NIC Link is Up 10 Gbps, Flow Control: RX/TX
Feb 24 13:28:53 node-0 kernel: bond0: link status definitely up for interface eth3, 10000 Mbps full duplex.

OS: CentOS 6.5
libvirt: libvirt-daemon-1.2.5-1.mira1.x86_64
Does anyone know the reason?