Explain the clustering technology behind Chime Meetings, and how this architecture scales across the enterprise.
- Chime intelligently groups browsers together to form clusters. By establishing clusters, a meeting will save on bandwidth and network resources by offloading some of the centralized collaboration traffic needs to the clustered participants' laptops or mobile devices. A cluster is comprised of endpoints in close network proximity to one another that transmit audio and video directly between themselves (peer-to-peer). Network proximity is not based on physical or geographic factors, but rather network performance measured by delay and jitter metrics between the endpoints, as monitored by the Chime server.
- A browser connects to Chime via a link (URL) which connects the browser to the Chime server. The Chime server will evaluate the endpoint, determine if it should create a new cluster or be attached to an existing one. Chime presently creates two types of clusters: WebRTC-based and Flash-based. Browser clusters are created based on capabilities found in the browser. In turn, a cluster may range from 1 - 8 participants. A single participant, dubbed the Uplink Node within the cluster, will be responsible for sending the media to the Chime server. The Chime server will, if needed, forward the cluster’s media to the appropriate meeting in Skype for Business, Cisco or SIP based conferencing solution.
- Within a cluster, Chime is efficient. Chime dynamically controls bit rate, resolution and framerate to minimize the encoding & decoding burden across nodes. With the active speaker larger bitrates, resolutions and frame rate are used, but non-active participants use less bandwidth and smaller resolutions. As more parties are added to a conference, we can be judicious in video resolution & quality just as MCUs and SFUs operate.
- Clusters can be created and destroyed as necessary during the life of a meeting. If network conditions change, participants and uplink nodes can be removed from a cluster at any time and reconnected through the Chime server directly. For customers that choose not to use clustering, this option can be disabled as a configuration selection.