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Quality of Service overview

You can configure a range of features on the Passport 1424T Routing switch that enable you to allocate network resources to mission critical applications at the expense of applications that are less sensitive to such factors as time delays or network congestion. You can configure your network to prioritize specific types of traffic, ensuring that they receive the appropriate Quality of Service (QoS) level.

On the Passport 1424T Routing switch, traffic prioritization allows you to manage bandwidth allocation for traffic flows on the LAN. These traffic flows are switched in hardware at layer 2 level.

On the Passport 1424T Routing switch traffic flows on the LAN are routed at layer 3 level through a differentiated services (DiffServ) network architecture. Traffic filtering is a mechanism that helps you to manage traffic by defining filtering conditions and associating these conditions with specific actions. Within a DiffServ network IP filtering allows you to assign QoS levels based on a range of filtering conditions.

Within the DiffServ network, the marked packets are placed in a queue according to their marking. For example, if a video stream is marked to receive the highest priority, it is placed in a high-priority queue. As those packets traverse the DiffServ network, the video stream is forwarded before any other packets.

By assigning QoS user class priorities to traffic flows on your LAN and WAN, you can ensure that network resources are allocated where they are needed most. To be effective, you must configure QoS functionality from end-to-end of the network: across different devices, such as routers, switches, and servers; across platforms and media; and across link layers, such as Ethernet, ATM, and frame relay.

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