Best Practice for Video over WLAN - Part 1
Wired Infrastructure Optimization for Multicast
There are four primary recommendations to consider in the wired network for supporting broadcast-quality video. Reference the User Guide provided by the appropriate wired infrastructure vendor to enable these settings:
1. Utilize Gigabit Ethernet End-to-End
It is recommended to have Gigabit Ethernet connectivity from the between all components in the path of video delivery. This includes Gigabit to the Video Server, Aruba Controller, and Aruba 802.11n APs.
2. Enable IGMP
IGMP proxy or IGMP snooping should be used to facilitate video delivery only to those APs with subscribers.
3. Configure Quality of Service Traffic Tagging and Prioritization
Traffic tagging and prioritization should be enabled in the wired network to provide Quality of Service (QoS) to the video streams. It is important to enable Layer 3 Video Differentiated Services Code Point (DSCP) tagging and Layer 2 802.1p tagging on the application (server and clients if possible), the controller(see below), and prioritization/QoS on the wired infrastructure for end-to-end QoS guarantees.
4. Adjust Video Frame Size
It is recommended to set the frame size at the video server low enough to avoid fragmentation, or enable jumbo frames to the largest supported size if possible. It is important to ensure the MTU of the video server is not larger than the maximum frame size on any wired segment. Fragmentation can be verified by monitoring the frame counters on the switch or router interface(s) along the video data path. Fragment loss results in the entire video frame being retransmitted, also increasing over the air bandwidth.
In the next part we will look at some of the optimizations required on the WLAN infrastructure to deliver multicast video on your network.