What is QoS? The best definition I heard is that QoS is „managed unfairness“ Different type of traffic is managed differently – make sense 😉 There are lots of QoS mechanism out there but all of them can be grouped to 3 gategories: Best effort – this is not strict DiffServ – less strict IntServ  Full Article…

We have different options for marking the traffic. Class of Service (CoS) – this is L2 marking. It uses the priority bits in the vlan tag 802.1Q. 3 bits make for us 8 classes available valued from 0 to 7. However cisco says 6 and 7 is reserved so 6 values left for us. When  Full Article…

RED belongs to congestion avoidance concepts as we spoke already. RED is an industry standard. Check the picture below. We got there output queue with minimum, maximum threshold and its whole capacity. If your queue is full you start dropping packets. We dont want that. Thats why we got minimum threshold. From that point we  Full Article…