300-430 Question 72
Select 2A network engineer is troubleshooting a wireless network experiencing high latency and packet loss during a multicast video stream. The network uses a Cisco Wireless LAN Controller (WLC) with clients in power-save mode. Which of the following actions can help mitigate the issue?
- A
Enable IGMP Snooping on the wireless network
- B
Configure multicast-to-unicast conversion on the WLC
- C
Increase the DTIM interval for the affected SSID
- D
Disable power-save mode for the client devices
- E
Reduce the multicast data rate on the WLC
Show answer and explanation
Correct answers: B, D
Explanation
When multicast traffic is transmitted in wireless networks, it is often sent at the lowest supported data rate, which can result in congestion and poor performance. Additionally, clients in power-save mode may experience delays in receiving multicast packets. Configuring multicast-to-unicast conversion allows the controller to send multicast traffic as unicast, improving reliability and reducing latency. Disabling power-save mode for clients eliminates the delay associated with buffering multicast traffic, further enhancing performance.
- A. Incorrect.
Enabling IGMP Snooping helps manage multicast traffic on wired networks by limiting the spread of multicast packets. However, it does not directly address wireless-specific issues like power-save mode or multicast performance.
- B. Correct.
Multicast-to-unicast conversion ensures that multicast packets are sent as unicast packets to clients, improving reliability and performance in wireless environments, especially when clients are in power-save mode.
- C. Incorrect.
Increasing the DTIM (Delivery Traffic Indication Message) interval delays the delivery of buffered multicast traffic, which can worsen latency for time-sensitive applications like video streaming.
- D. Correct.
Disabling power-save mode ensures that client devices remain active to receive multicast traffic without delay, improving performance in scenarios where multicast data is critical.
- E. Incorrect.
Reducing the multicast data rate can result in better coverage, but it may also cause increased airtime usage and congestion, which can worsen latency and performance issues.