When planning a high-availability Zixi deployment it is important to consider timing issues. The various types of redundancy configurations offer different retry timings, which are critical to calculating the overall video dropout at the target. Based on the latency settings that have been configured, Zixi Broadcaster acknowledges disconnection after a connection loss that exceeds the latency period and then retries to establish a connection. The cause of the connection loss also determines the time it takes for Zixi Feeder to acknowledge a drop. This can take up to 25 seconds in the worst case scenario.
For more detailed retry timing data, please contact your Zixi representative. 
The hitless failover configuration involves grouping two inputs in a "Failover Group". If the two inputs are identical (i.e. two or more binary-identical streams with synchronized RTP headers), when one of them is disrupted or interrupted completely, Zixi Broadcaster will seamlessly use the packets of the other input without any disruptions.
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If the streams are not identical, the failover process will not be seamless and may take up to a second. |
A Failover Group can comprise two or more inputs. In a group of three or more, you can define one or more streams as a "Backup". In this case the system will always try to recover packets from "Primary" streams first and only if there are no available primary streams, it will use the backup streams. When one of the primary streams becomes available, the system will automatically jump to the primary stream.
While the Broadcaster GUI only enables configuration of primary streams at a single priority level, through the Zixi Broadcaster API it is possible to assign different priorities as follows:
- Priority 0 – means backup. It will be used only if all other streams are unavailable.
- Priority greater than 0 - means primary.
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Failover between streams that have different priorities, even primary streams, will not be seamless and may take up to a second. |
The Failover Group has its own Stream ID, just like an Input Stream, and will appear in the Inputs list.
Although the topology above shows only one Zixi Broadcaster, it is also possible to have multiple targets (e.g. two or more Zixi Broadcasters), each with its own Failover Group of inputs to enable a more complete system-level redundancy.