While MobileConnect/CinemaConnect might function also in networks with cheap and / or misconfigured infrastructure, users might well experience increased audio latency, audio dropouts or even failure of the streams especially when more than a handful of clients try to connect.

To optimize your network for perfect MobileConnect/CinemaConnect reception, please observe the recommendations made by this document closely and keep monitoring the system during use.

Yet, detailing strategies for deployment of a workable WiFi network would exceed the scope of this document. If you want to provide excellent streaming service to a maximum number of users, you’ll have to be careful in designing your infrastructure to high standards.

 

 

The following application note on the Sennheiser website gives a short and comprehensive overview of the network requirements:

 

 

For detailed information continue reading the following paragraphs.

 

To estimate the impact on your WiFi network to expect from a MobileConnect/CinemaConnect installation, we give some insight into what traffic to expect:

When using multicast discovery, the server ConnectStation will send out small announcement packets on the port specified, to the multicast group address specified, twice per second.

ConnectStations that form a cluster will communicate with each other on ports in the 8000-9000 range, both via TCP and UDP. The traffic involved should stay minimal and not pose a problem to any cabled infrastructure.

WiFi Clients with the MobileConnect/CinemaConnect App will use a discovery method as described above, and cause some registration traffic via http on port 8000, and keep a TCP control connection open in the 8000-9000 range. Whenever a change in configuration is detected, clients are triggered to re-request the channel configuration via http. If many clients are connected, this will cause http transfers which vary in size depending on the amount of ConnectStations and Channels configured in the cluster.

The most serious amount of traffic though will obviously be the audio streaming data which is sent via UDP on ports 3200-3400. Audio data is sent via UDP unicasting to each client registered for a stream. Every client receives around 100 packets per second, each 96 bytes plus UDP/IP/WiFi overhead. That is with our current recommended settings. In some circumstances, the system might increase the packet count up to 400 packets/s, and while the payload size per packet will go down accordingly, obviously header overhead stays the same, resulting in a higher overall data rate.

Note: It's important that these packets are delivered by your infrastructure in a timely fashion, ideally without any frame aggregation taking place, to keep audio latency down.

To allow prioritization of the streaming data on both your cabled infrastructure and - more importantly - with your WiFi equipment, we are tagging the traffic with DSCP 0x2E (EF). Please ensure that this traffic is handled accordingly, for example, it should usually end up in the WiFi Access Point’s VO queue.

 

With the Access Points delivered with the MobileConnect/CinemaConnect System (Ruckus ZF7372), we’ve seen the best results with 40MHz channel width in the 5GHz bands, but 20MHz on 2.4GHz.

In order to ensure best possible streaming quality, we recommend to have maximum of 50 clients per Ruckus 7372 access point due to the following reasons:

When using more than one ConnectStation or increasing the number of clients per ConnectStation with your own WiFi infrastructure, especially if clients also use the WiFi for other purposes, you will have to take measures to ensure that enough bandwidth is available for streaming.

For more information see "WiFi planning".

 

Smartphone clients need to be able to connect to the ConnectStations as directly as possible. They need to get IPs assigned from your DHCP that are in the same broadcast domain as those assigned to the ConnectStations.

As far as possible, avoid too many switches and routing on Layer 2 between smartphone clients and ConnectStations. Any switch can introduce jitter and congestion, which will increase audio latency experienced by MobileConnect/CinemaConnect users or even cause the streams to stop working altogether.

You’ll need to support one of the service discovery option for the clients, as described in "Service discovery (Integrated Mode)".

If you want to integrate more than one ConnectStation into your network, you’ll also need to support a cluster discovery option as described in "Cluster discovery (Integrated Mode)".

Modern mobile devices require an internet connection at all times. When connecting to a WiFi the devices may reject the network if there is no internet access. The MobileConnect/CinemaConnect system provides additional features to allow mobile devices to seamlessly connect to the MobileConnect/CinemaConnect WiFi. However, we cannot guarantee that all mobile devices on the market will be covered. We recommend providing internet access in the network for better client connectivity.

 

We strongly recommend to use enterprise-grade switches and WiFi equipment and keep a close eye on the delivery of our data especially when the installation needs to support a large amount of simultaneous listeners.

Our audio streaming traffic is similar in structure to VoIP traffic, so lots of lessons learned there will apply here, too. The main difference is that our traffic is mostly unidirectional, i.e., there is not much data traffic originating from the client devices. Keep this in mind when configuring WMM and QoS settings in your network and WiFi controllers.

Any cabled infrastructure should be Gigabit Ethernet or better.

 

The bandwidth usage is similar as for Voice over IP.

The system creates a bandwidth of 90 - 200 kbit/s per client. Please be aware that in WiFi, the actual throughput can diverge significantly from the basic rate.