Quality of Service (QoS)

Quality of Service

• End to end L3 QoS using MQC

  Quality of Service (QoS) is a mechanism or technology that handles network traffic and allocates capacity to ensure the performance of critical applications. All QoS mechanisms are designed to resolve or reduce bandwidth overutilization, delay, flapping, and packet loss in a network.

• DiffServ

• CoS and DSCP Mapping

• Classification & Marking

  . QoS classification refers to the process of classifying the type of IP packets or traffic. Traffic types can be data, video, or voice traffic.

• Convert marking to default

• Network Based Application Recognition (NBAR)

  NBAR is a deep packet inspection tool used to classify and recognize a wide range of protocols and applications utilizing data from Layer 3 to Layer 7, including applications that dynamically assign TCP and UDP port numbers.

• Marking using IP Precedence, DSCP, CoS

• Software Queue, PQ, CQ, WFQ, CBWFQ, and LLQ 

• Tail drop

• Types of Delay

  • Processing delay – time it takes a router to process the packet header

  • Queuing delay – time the packet spends in routing queues

  • Transmission delay – time it takes to push the packet's bits onto the link

  • Propagation delay – time for a signal to propagate through the media

• Policing, shaping

  Traffic shaping is a QoS tool that allows higher-priority traffic to flow at optimal levels even when the bandwidth is highly utilized (prioritize traffic).

• Congestion management and avoidance

  Congestion, in the context of networks, refers to a network state where a node or link carries so much data that it may deteriorate network service quality, resulting in queuing delay, frame or data packet loss and the blocking of new connections. In a congested network, response time slows with reduced network throughput.

• QOS over VPN