[ovs-discuss] QoS Rate Limiting on VxLans OvS

[Justin Pettit]

> On Aug 19, 2016, at 3:26 AM, Waseem Ullah <waseemullah999 at gmail.com> wrote:
> 
> Hello All,
> 
> I have Successfully created an overlay network of two Hosts, a Switch(OVS) and Controller. I tried to Implement  QoS Rate Limit on the hosts.  the Issue i am facing is When i set the Ingress Rate on VM1 and send traffic to VM2 using iperf i Don't See it applied. But When i Try to send traffic from VM2 with No Ingress Set on it the Ingress is limit is applied. For Some reason the Ingress Limit is Applied on Receiving End Not Sending End. 

This is kind of confusing, but QoS policies are applied to egress ports from the point of view of OVS.  Here's an explanation from the FAQ:

Q: Does OVS support Quality of Service (QoS)?

A: Yes.  For traffic that egresses from a switch, OVS supports traffic
   shaping; for traffic that ingresses into a switch, OVS support
   policing.  Policing is a simple form of quality-of-service that
   simply drops packets received in excess of the configured rate.  Due
   to its simplicity, policing is usually less accurate and less
   effective than egress traffic shaping, which queues packets.

   Keep in mind that ingress and egress are from the perspective of the
   switch.  That means that egress shaping limits the rate at which
   traffic is allowed to transmit from a physical interface, but not the
   rate at which traffic will be received on a virtual machine's VIF.
   For ingress policing, the behavior is the opposite.

--Justin