Implementing QoS for Cisco Enterprise Wireless Networks - Trust Model for Switch Ports

Trust Model for Switch Ports

Question

A network engineer wants to implement QoS across the network that supports multiple VLANs.

All the APs are connected to switch ports and are configured in local mode.

Which trust model must be configured on the switch ports to which the APs are connected?

Answers

Explanations

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A. B. C. D.

C.

To implement QoS (Quality of Service) across a network that supports multiple VLANs and where all the APs (Access Points) are connected to switch ports and are configured in local mode, the network engineer must configure the appropriate trust model on the switch ports to which the APs are connected.

The trust model defines how the switch will treat packets received on a specific port based on their QoS markings. The trust model can be based on different QoS markings such as CoS (Class of Service), DSCP (Differentiated Services Code Point), or IPP (IP Precedence). WMM UP (Wireless Multimedia User Priority) is a QoS mapping for 802.11e wireless frames.

In this scenario, since the APs are connected to switch ports, it is recommended to configure the trust model to CoS. CoS is a 3-bit field in the 802.1Q VLAN header that allows up to eight levels of priority to be assigned to Ethernet frames. CoS is typically used in a LAN environment where QoS markings can be trusted end-to-end.

When the APs are connected to switch ports configured with the CoS trust model, the switch will use the CoS value in the 802.1Q VLAN header to determine the priority of the traffic. The switch can then apply different QoS policies based on the priority level of the traffic to ensure that high-priority traffic is given preferential treatment over low-priority traffic.

In summary, the trust model that must be configured on the switch ports to which the APs are connected in this scenario is CoS.