Home » Archive by categoryQoS

QoS Congestion Avoidance

Tail Drop Tail Drop is when the packets are dropped when they arrive on a congested interface.Tail Drop is not just bad for voice packets but for data packets as well. It also impacts the efficiency of network bandwidth utilization. When the Output Queue is full and packets ...
Continue reading

CBWFQ and LLQ

Class Based Weighted Fair Queueing РCBWFQ CBWFQ is a modern congestion management technique and it is not advised for Voice and Video traffic, since both of them need strict priorities.  CBWFQ uses the Cisco MQC command structure. With CBWFQ you can define traffic classes and assign guaranteed...
Continue reading

Custom Queuing and Priority Queuing

Custom Queuing (CQ) This is a Legacy technology for Congestion management. There are no dynamic Queues generated in CQ, instead you have to manually define the Queues. A maximum of 16 Queues can be defined and System Queue is Queue – 0 which is used for Layer-2 keepalives...
Continue reading

Queuing and WFQ

Queuing comes into action when the interfaces are congested. Queuing techniques are used to manage the congestion. The reasons for a physical interface to experience congestion may be 1. Speed mismatched (traffic moving from LAN to WAN) 2. Traffic aggregation ( Traffic coming to one location from multiple...
Continue reading

QoS Configurations

Sample Configuration using NBAR to rate limit certain traffic types. HTTP and HTTPS to be Rate Limited to 500 Kbps FTP Rate Limit to 100 Kbps Drop all Recognized Peer-to-Peer File Sharing Application  Traffic Configure using NBAR to Police Traffic going out to internet. 1. Define Class-Maps For...
Continue reading