300-425 Question 84
Select 3An organization has deployed a Cisco wireless network for their office. They want to enable Bonjour services, such as AirPlay and AirPrint, across different VLANs on their network. The administrator decides to implement mDNS to achieve this. What is a necessary step to allow mDNS service announcements to be exchanged across VLANs?
- A
Enable mDNS Snooping on the wireless LAN controller (WLC).
- B
Ensure that multicast routing is enabled on the network.
- C
Configure an mDNS Service Policy to specify which services should be advertised.
- D
Enable IGMP Snooping on the access points.
- E
Assign the same VLAN for all mDNS-capable devices.
Show answer and explanation
Correct answers: A, B, C
Explanation
To enable mDNS service announcements across VLANs, mDNS Snooping must be enabled on the WLC to manage and forward mDNS traffic. Additionally, multicast routing is needed to route the multicast mDNS packets between VLANs. Configuring an mDNS Service Policy ensures that only relevant services are advertised. IGMP Snooping and placing all devices in the same VLAN are not sufficient or necessary for this scenario.
- A. Correct.
Correct. Enabling mDNS Snooping on the WLC is a key step that allows the WLC to inspect and manage mDNS traffic, facilitating service discovery across VLANs.
- B. Correct.
Correct. Multicast routing is required to forward mDNS packets across different VLANs, as mDNS typically operates using multicast traffic.
- C. Correct.
Correct. An mDNS Service Policy is necessary to control which mDNS services should be advertised, ensuring only relevant services are propagated.
- D. Incorrect.
Incorrect. While IGMP Snooping is useful for multicast traffic management, it is not specific to the mDNS operation and does not replace other necessary configurations for mDNS across VLANs.
- E. Incorrect.
Incorrect. Assigning the same VLAN for all devices defeats the purpose of using mDNS across VLANs and does not address the need for inter-VLAN communication.