QoS is the ability of a network to provide improved service to selected network traffic over various underlying technologies. The increasing need for real-time traffics such as video streaming and VoIP has made QoS as an important requirement for a #reliable network. It decreases the Network Congestion# and the effect on the quality of the critical packets especially low delay and low jitter. QoS can potentially filter out malicious low prioritised packets (from unknown type or origin) as a policing mechanism, but it is still vulnerable to DDoS and concealed traffic.
Quality of Service (QoS)
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Switch
Switch provides means to resolve Network Congestion#, e.g. Quality of Service (QoS)#
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Scavenger QoS
Scavenger QoS imposes a traffic limit on ports, and if the packets exceeding the limits, it will be marked to lower priority, and might be dropped eventually. If we know an application’s normal behaviour on a device and on the network, a safeguard could be built using Scavenger QoS to recognise and stop the application upon abnormal behaviours. It works in the opposite way of Quality of Service (QoS)#. It reduces Network Congestion and possible DDoS or worm attacks especially if the attacks create a traffic spike (exceeding bandwidth thresholds) for sustained periods.
- Network Reliability
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Multiprotocol Label Switching (MPLS)
Several enhancements are done in MPLS in order to improve the overall traffic flow in the network. MPLS network chooses the shortest path for a traffic flow based on the size and priority of a traffic flow. Therefore, it can honour IP Quality of Service (QoS)#.
Within the WAN that implements MPLS, all packets will be assigned a label by a Router (just before entering the MPLS network), based on IP destinations, IP sources, Quality of Service (QoS)#, VPN membership or engineered specific routes, in order to differentiate from each other in the MPLS network. The packet will then be forwarded to the MPLS core routers, and they will apply appropriate services and forward it based on its label. As the packet reached the destination edge of the MPLS network, the label will be removed from the packet. They are usually 4 bytes (32 bits) long.
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Differentiated Service
Differentiated Service could be used to categorise the type of the network traffic especially when needing to provide Quality of Service (QoS)#. To do that, it uses at least 4 bits to show the 4 types of type of service (TOS), shown at below that the traffic is.