QOS LLQ

[Ratheesh mv]

As per this screenshot , In the LLQ que ,If traffic is keep on coming and hitting in the priority que at below policy rate (LLQ) then how are packets served from other ques?

If I have data in other ques  ,are those serve after serving complete packets from LLQ? 

When does IOS really place packets in software que? is it  happen always or only whenever congestion is occurred? 

Thanks in advance 

[Joseph W. Doherty · Accepted solution]

I would say the diagram is accurate.

Q1: Non-LLQ queues are serviced when there's not LLQ packets.

Q2: Yes.

Q3: Software queues form from the "overflow" of the TX-Ring queue.  (Early on, working with Cisco QoS, I noticed it didn't seem to be working as well as I expected.  This due to the TX-Ring queue filling first, and it being a FIFO queue.  The way to mitigate this is to reduce its size.)