03 December 2019

Disabling directed multicast on Ruckus Unleashed network



Ruckus has a Directed Multicast feature, enabled by default, that will give first 5 multicast
members a TCP rather than UDP message, with better delivery expectations.

Quote from Ruckus:
There are three mechanisms that Ruckus employs to help multicast applications work better.
1. Directed Multicast uses IGMP snoop to determine which devices are requesting access to a multicast session and then implements a multicast to unicast conversion, since Multicast implies multiple users receiving the same packets simultaneously and since WiFi clients can each be receiving at different Data Rates based on statistical success.

2. Multicast packets are traditionally sent at the broadcast, multicast, frame header - lowest common denominator rate – for 802.11bgn that is 1Mbps.

3. Directed multicast will send each client that subscribes to a multicast session an individual copy of each multicast packet sent as an 802.11 unicast at the highest speed that particular client can receive.

Instead of having one 1Mbps packet sent to several clients you get several unicast packets (that also get acknowledged) sent at 54Mbps to 300Mbps (for 802.11na).  There is a threshold (that can be sent) above which the number of simultaneous viewers of the same multicast diminishes the efficacy of this process.  To learn which clients desire access to the multicast the Ruckus Access Points do IGMP snooping and create a table of client join and leave messages.

Directed Multicast, IGMP snoop and IGMP queries are enabled in each logical interface – Ethernet, and WLAN/SSID.

In specific scenarios you may want this feature to be disabled, so we let IGMP work and flood AP WLANs with client multicasts. Not only after more than 5 members, but immediately.

The key is to determine exactly which SSID you want to do this on, next configure the system to disable the directed multicast feature.
SSH to your primary unleashed AP. Then issue the following commands:
ruckus# config
You have all rights in this mode.
ruckus(config)# wlan TheSSID
The WLAN service 'TheSSID' has been loaded. To save the WLAN service, type 'end' or 'exit'.
ruckus(config-wlan)# no qos directed-multicast
The command was executed successfully. To save the changes, type 'end' or 'exit'.
ruckus(config-wlan)# no qos igmp-snooping
ruckus(config-wlan)# end
The WLAN service 'TheSSID' has been updated and saved.
Your changes have been saved.
ruckus(config)#

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