QoS classification, tagging, and traffic distribution processes

Two models of QoS classification, tagging, and traffic distribution process QoS: Integrated Service and differential service. When QoS is implemented, traffic-based features are first classified and different levels are marked on the edge of the network; NBAR: an advanced classification method that supports high-level application information classification; Layer 2 QoS: 802.1 p & CoS (TAG field); Layer 3 QoS: Ip precedence, DSCP (ToS field); queuing technology is under the premise of congestion; RTP protocol is the highest level, priority forwarding, as EF, UDP range 16384-16384 + 16383; WRR: there are 4 weighted cyclic queues, which can be manually assigned a certain priority to a queue, and a bandwidth allocation ratio can be determined when the stack is released; use pseudo discard (tail drops) it can cause large jitter. WRED can be used to capture several low-priority packets first, so as to avoid TCP synchronization. TCP synchronization will not occur as long as the queue does not reach the full limit. Congestion Control Technology: Traffic Shaping: make the traffic stable; traffic policy: Mark some packets and give priority to them; packet sharding: Cut the packets into long fragments, and the transmission interval is stable; MQC is a modular QoS; implement QoS using MQC: class-map-> policy-map-> service-policy; Enable QoS: mls qos on a multi-layer switch; border of configuration trust: mls qos trust (cos | dscp | ip predencel) trust the priority information carried by the inbound stack traffic. Several observed commands: Configure class-based labels: (modify the TOS field) policy-map-> class-> set ip precedence; NBAR: QoS provided at the application layer: guaranteed bandwidth, Traffic Shaping, etc.; with NBAR: class-map-> match protocol-> policy-map-> class-> service-policy, it can be used as a traffic indicator. By default, the bandwidth of interfaces used by the queue cannot exceed 75%, which can be changed. CBWFQ is a subset of MQC. The following is the abbreviation of a mess of 78: ----------- WFQ-AF; PQ--EF; CBWFQ can contain LLQ; LLQ--EF; FIFO -- default, no queue mechanism; CQ--EF; WRED -- can be used for CBWFQ;