[ovs-discuss] Port satturation?

Vladimir Nikolić vladimir.nikolic at amis.si
Tue Oct 11 22:30:12 UTC 2011

Yes, there are occasionally arp records (showed by tcpdump on VM2), but
there is 1000x more records for unicast traffic between VM1 and syslog
server. I can see that traffic on VM2 (vif2.0) and xapi2 interface


On 12. 10. 2011 00:12, Jesse Gross wrote:
> 2011/10/11 Vladimir Nikolić <vladimir.nikolic at amis.si>:
>> Hi,
>> we are expiriencing some very strange behaviour on our XenServer 6.0
>> server (openvswitch-1.0.99-104.9871).
>> On fake bridge xapi2 we have 2 VM, each with one interface:
>> # ovs-vsctl list-ports xapi2
>> vif1.0 (VM1, ip
>> vif2.0 (VM2, ip
>> VM1 is mail server, with traffic peaks at 15Mb/s. Mail logs are sent to
>> syslog server ( which is on the same vlan as VM1 and VM2.
>> Problem is that VM2 is receiving some unicast traffic that is sent from
>> VM1 to servers on same vlan (99.9% of that traffic is UDP):
> Does the syslog server ever transmit?  I'm guessing that it does only
> very rarely since it is receiving UDP unicast packets.  If it does not
> transmit, then Open vSwitch will not know where to send the traffic
> and will flood it to all ports.  Eventually when the server does
> transmit for some reason (i.e. ARP response) the MAC will be learned
> and traffic is directed to it but eventually the MAC will age out
> until it transmits again.

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