Directed Multicast

Directed Multicast optimizes the delivery of multicast traffic by converting it into unicast traffic under certain conditions.

Multicast traffic is typically used to send data to multiple recipients simultaneously, such as streaming video or audio to multiple users. However, multicast traffic can be inefficient in wireless networks because it is transmitted at lower data rates to ensure all clients can receive it, which can lead to network congestion and reduced performance. Directed Multicast addresses this issue by converting multicast packets into unicast packets, which are sent directly to each client at higher data rates, improving overall network efficiency and performance.

This feature allows administrators to control multicast conversion from various sources, including wired, wireless, and network sources, to unicast. For instance, administrators can decide whether multicast traffic from a wired source should be converted to unicast when sent to wireless clients, or vice versa. When Directed Multicast is enabled, the AP checks if a multicast packet is well-known (e.g., Bonjour, uPNP, most IPv6 link- and node-local, and Spectralink) and takes one of the following actions:

  • For well-known packets: The AP applies the Directed Threshold for unicast conversion.
  • For non-well-known multicast types: The AP uses IGMP (Internet Group Management Protocol) and MLD (Multicast Listener Discovery) to monitor client subscriptions. If clients are subscribed, the AP converts packets to unicast regardless of the Directed Threshold. If no clients are subscribed, the AP drops the packets.

When Directed Multicast is disabled, the AP solely uses the Directed Threshold to determine whether to transmit a multicast packet as unicast.

Note: The configuration options for Directed Multicast are available at the Zone, AP Group, or AP level. For configuration instructions refer to the RUCKUS SmartZone AP and Switch Management Guide. For instructions to configure Directed Multicast settings through AP CLI, refer to the RUCKUS SmartZone Troubleshooting and Diagnostics Guide.

The practical use case scenarios where Directed Multicast is helpful include corporate office settings where multicast video content from a central server is converted to unicast when sent to wireless clients in conference rooms. On a university campus, multicast is often used for live streaming lectures to students' devices from wireless sources, such as a professor's tablet, which can be converted to unicast to maintain high-quality streams and reduce network congestion. In enterprise networks, multicast is commonly used for distributing software updates and patches to multiple devices. Administrators can control whether this multicast traffic from network sources, like a central update server, is converted to unicast when sent to wireless clients, ensuring efficient and reliable delivery of updates without overloading the network.

Parent topic: Traffic Management