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WLAN Infrastructure Connections and LAG

22 questions

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Question 21Question →

A network administrator is setting up a branch office deployment with Cisco Access Points (APs) operating in FlexConnect mode. The APs need to locally switch traffic for client WLANs mapped to corporate VLAN 20 and guest VLAN 30, while using VLAN 10 for AP management and CAPWAP control traffic back to the WLC. Which switch port configuration must be applied to the switch interface connected to each FlexConnect AP?

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Answer: Configure the switch port as an 802.1Q trunk port with Native VLAN 10 and allowed VLANs 10, 20, and 30.

Answer

The switch port must be configured as an 802.1Q trunk port with Native VLAN 10 (for untagged AP management/CAPWAP traffic) and allowed VLANs 10, 20, and 30 for local client traffic switching.
FlexConnect APs configured for local switching handle client traffic locally at the branch level. To support multiple SSIDs mapped to different VLANs (VLAN 20 and 30) alongside AP management traffic (VLAN 10), the connected switch port must be an 802.1Q trunk. Untagged AP management traffic maps to the native VLAN (VLAN 10), while client traffic is tagged with its respective local VLAN IDs.

Step-by-Step Solution

1
Identify the operational mode of the Access Point.
The AP is in FlexConnect mode performing local switching for client traffic.
FlexConnect APs process VLAN tags locally on their physical Ethernet interfaces for traffic sent directly to the local switch infrastructure.
2
Determine the interface type required on the switch.
An 802.1Q trunk interface is required because multiple VLANs (VLAN 10, 20, 30) must traverse the single link connecting the AP.
Access ports can only carry a single VLAN, which is insufficient for multi-VLAN local switching.
3
Determine Native VLAN assignment for AP management.
Set Native VLAN to VLAN 10 on the switch trunk port.
Cisco APs transmit untagged management traffic by default. The native VLAN on the switch trunk port ensures untagged packets from the AP are placed onto management VLAN 10.

Key Concept

FlexConnect AP Infrastructure Switch Port Trunking Requirements
Question 22Question →

A network engineer needs to configure link aggregation (LAG) on a Cisco Catalyst switch connected to a Cisco AireOS Wireless LAN Controller (WLC). Arrange the following configuration steps in the correct logical order from first to last to ensure a functional static EtherChannel interface on the switch.

Drag items to arrange them in the correct order

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Answer

The correct order of steps is: 1. Create and enter interface configuration mode for the logical port-channel interface. 2. Configure switchport trunking encapsulation, trunk mode, and allowed VLANs on the port-channel interface. 3. Select the range of physical member interfaces connected to the WLC distribution ports. 4. Bind the physical member interfaces to the port-channel using channel-group mode on.
The correct operational sequence begins by creating the logical port-channel interface and setting its trunking and VLAN parameters. Next, the network engineer selects the physical switch interfaces connected to the controller's distribution ports and assigns them to the channel group using 'mode on'. Static aggregation is required because AireOS WLCs use unnegotiated bundle distribution across all active ports.

Step-by-Step Solution

1
Create the logical port-channel interface on the Catalyst switch.
The port-channel interface (e.g., interface Port-channel 1) is instantiated.
Establishing the logical bundle interface first provides a central point to apply trunking properties.
2
Apply 'switchport mode trunk' and allowed VLAN commands to the port-channel interface.
The logical interface is configured as an 802.1Q trunk carrying required WLAN management and data VLANs.
Applying configurations to the port-channel interface prevents port inconsistency errors across member links.
3
Enter interface range mode for the physical switch ports connecting to the WLC.
Physical ports (e.g., interface range GigabitEthernet1/0/1 - 2) are selected.
Physical interface mode is needed to assign the specific physical links into the aggregated bundle.
4
Issue the 'channel-group 1 mode on' command on the physical interfaces.
Physical interfaces join the port-channel as static EtherChannel members.
Cisco AireOS Wireless LAN Controllers do not negotiate LACP or PAgP control frames; the switch ports must use static channel mode 'on'.

Key Concept

Switch EtherChannel Configuration Sequence for AireOS WLC Link Aggregation
Estimated Time:1m 30s
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