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[Launchpad Bug Tracker <1200945@xxxxxxxxxxxxxxxxxx>]

[Expired for neutron because there has been no activity for 60 days.]

** Changed in: neutron
       Status: Incomplete => Expired

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https://bugs.launchpad.net/bugs/1200945

Title:
  Wrong configuration cause ARP broadcast storm

Status in OpenStack Neutron (virtual network service):
  Expired

Bug description:
  Hi, When I use quantum in my Env（CentOS6.3 Grizzly , quantum (OVS ，VLAN mode), I have the following issue.
  I  config ovs_quantum_plugin.ini wrong at first time, After I modify the config of ovs_quantum_plugin.ini and restart quantum-openvswitch-plugin, I find a loop on OVS bridge br-eth2. This will cause ARP broadcast storm. 

  Steps:
  At first, I config integration_bridge error in ovs_quantum_plugin.ini,  it should be br-int, but I config it  "br-eth2".
  The config is like following:
  [OVS]
  tenant_network_type=vlan
  network_vlan_ranges = default:2000:3999
  integration_bridge = br-eth2
  bridge_mappings = default:br-eth2

  
  Then, I modify the integration_bridge to br-int, and restart quantum-openvswitch-agent. ARP  broadcast storm happen.

  
  I check the OVS, and find that "int-br-eth2" and "phy-br-eth2" are on bridge "br-eth2".  And they will cause a switch loop, then cause ARP broadcast storm. 
  But in fact, "int-br-eth2" should be on br-int.
   
  # ovs-vsctl show
  da8de9ec-5bc7-447f-a5fa-e84d8a35f953
      Bridge "br-eth2"
          Port "int-br-eth2"
              Interface "int-br-eth2"
          Port "phy-br-eth2"
              Interface "phy-br-eth2"
          Port "br-eth2"
              Interface "br-eth2"
                  type: internal
      Bridge br-int
          Port br-int
              Interface br-int
                  type: internal
      ovs_version: "1.10.0"

  
  ARP broadcast storm makes the RX packets of int-br-eth2 & the TX packets of phy-br-eth2 become Huge number within several seconds:
  #ifconfig
  ...
  int-br-eth2 Link encap:Ethernet  HWaddr 76:31:AF:C6:D0:F5  
            inet6 addr: fe80::7431:afff:fec6:d0f5/64 Scope:Link
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:124576552 errors:0 dropped:0 overruns:0 frame:0
            TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:1000 
            RX bytes:9732214772 (9.0 GiB)  TX bytes:468 (468.0 b)

  phy-br-eth2 Link encap:Ethernet  HWaddr F6:6A:E6:81:6C:A4  
            inet6 addr: fe80::f46a:e6ff:fe81:6ca4/64 Scope:Link
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:6 errors:0 dropped:0 overruns:0 frame:0
            TX packets:124576753 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:1000 
            RX bytes:468 (468.0 b)  TX bytes:9732230474 (9.0 GiB)
  ...

  
  Although I config error at first, but I think after I modify the config right, it should work well. But in fact this will cause ARP broadcast, I think it is very dangerous. Is this a issue?

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