Once a packet is identified, it is typically marked near the source of the traffic flow, allowing the packets to receive differentiated treatment. Marking is typically done at the Layer 3 IP header using the Differentiated Services Code Point (DSCP); LAN implementations use the Class of Service (COS) field.

Quality of Service (QoS) is a set of technologies that work on a network to guarantee its ability to dependably run high-priority applications and traffic under limited network capacity. QoS technologies accomplish this by providing differentiated handling and capacity allocation to specific flows in network traffic.

Misconfigured QoS: If QoS is misconfigured, it can add latency as the wrong packets may be getting delayed in a buffer when other traffic is present. ... Too Many Network Devices: Each network device involved in a communications path will add a little bit of latency to the conversation.

Overview. Quality of Service (QoS) DSCP Marking is used to determine traffic classification for network data. This can be used to determine which network traffic requires higher bandwidth, has a higher priority, and more likely to drop packets. ... If the DSCP markings are ever changed, the MSI will need to be re-deployed.