Load balancing, redundancy and scalability

This topic summarizes the load balancing, redundancy and scalability aspects of Pexip Infinity.

Load balancing

Pexip Infinity load-balances intelligently across all Conferencing Nodes that are grouped within a system location, and can also utilize media overflow locations when all of the conferencing resource within a location has reached its capacity.

Signaling

  • The load balancing of signaling across Conferencing Nodes in a single location is achieved via your call management system and/or DNS SRV records. They should be configured so that calls from your endpoints or other systems are routed to only those Conferencing Nodes that you want to receive signaling.
  • Signaling always remains routed to the node that received the call. This could be a Proxying Edge Node or a Transcoding Conferencing Node.

Media

  • If the signaling is received on a Proxying Edge Node, media proxying is allocated to the proxying node with the most available capacity in the location that received the signaling. The selected proxying node will always handle the media connection with the endpoint, acting as a proxy between the endpoint and a Transcoding Conferencing Node (which should be in a different location).
  • If the signaling is received on a Transcoding Conferencing Node, then whichever transcoding node is selected to process the media (which may be a different node to the signaling node) will also directly handle the media connection with the endpoint.
  • You can nominate which location's Transcoding Conferencing Nodes to use to process the call media (either directly or proxied), based on the location of the node that is handling the call signaling. If a transcoding node in the nominated location is already processing media for the conference, and it has spare capacity, then it will also process the media from the new caller, otherwise the transcoding node that currently has the most available capacity is selected to process the media (up to a maximum of three transcoding nodes per location per conference instance). If there is no transcoding resource available in that location, then transcoding nodes in the overflow locations (if configured) are used. The selection of the transcoding node in the media overflow location follows the same balancing rules: if a node is currently processing the conference media and has capacity to take the new call then that node is selected, otherwise the node in the overflow location that currently has the most available capacity is selected.

For full details about how media is routed, load-balanced and directed to overflow locations, see Handling of media and signaling.

For further information about how to configure your specific call management system to work with Pexip Infinity, see the following documentation:

Redundancy

Management Node

The Management Node is used to manage Conferencing Nodes, configure conference settings, manage licenses and collate system logs. It does not handle any call processing, so if it were to become unavailable the Pexip Infinity service would be unaffected. However:

  • You would not be able to make changes to services (Virtual Meeting Rooms, Virtual Receptions and so on).
  • Logging would be affected: the Management Node would not receive and collate logs from the Conferencing Nodes. This can be mitigated by using a syslog server to collate logs.
  • After 14 days, licenses would cease to be allocated and the Pexip Infinity service would no longer allow calls.

Conferencing Nodes

You should ensure that your call control system is set up so that, in the event of a Conferencing Node failing, new calls to the conference are routed to another available Conferencing Node.

Basic alternate gatekeeper support is available for H.323 endpoints. When a H.323 device makes a registration request, the Conferencing Node returns a list of any alternate nodes in the same Pexip system location; the device will attempt to use an alternate should the original node be unresponsive.

If multiple Conferencing Nodes are configured in a single location, new calls to a conference can be routed by the call control system to only those nodes that are currently available. To achieve this, you must configure the call control system with all possible Conferencing Nodes (either explicitly or through DNS records), and for liveness checks to be carried out.

Note that there is no live failover; calls in progress on a Conferencing Node that fails will be lost, and participants will need to redial to reconnect to the conference.

Scalability

To increase the capacity of the Pexip Infinity platform, simply deploy one or more new Conferencing Nodes. You may also need to increase the number of call licenses.