Grass Valley iTX Output Server 2 v.2.6 - Manual (Page 10)

4
Introducing Output Server 2
Playout Type Support
In order to transmit appropriate branding for a simulcast channel, iTX allows users to
configure event substitution rules, which can be used to swap assets such as logos and CGs
based on their names in the main channel’s schedule.
iTX manages the broadcasting of main and simulcast channels using a system of
networked instances of TXPlay 2, known as a leader/follower network. The main channel in
any iTX system is identified as a leader channel. When a simulcast channel and its
corresponding backup channels are added to the iTX system, they are designated as
followers. See
About Leader/Follower Channel Communication on page 4 for more
information about the leader/follower model.
Playout Type Support
The table below shows which playout types are available to the supported models of AJA
SDI I/O card:
Playout Type K3G C1 C44 C88 Comment
Single channel     Default for all models of SDI I/O card. Use for stand
alone main or backup channels.
Dual Channel   Select to configure two channels running on the
same playout server (i.e. channel A main and channel
B backup).
Simulcast   Select if you are configuring a simulcast channel on a
separate playout server or you are configuring main
and simulcast channels on the same playout server.
Simulator N/A Select for test channels only.
About Leader/Follower Channel Communication
When configuring a main channel and its backup in Output Server 1, it communicates
between the two channels using a master/slave model. The two channels share the same
configuration, schedule, assets and iTX Desktop controls, and changes to any of these on
the main channel (the master) are also sent to the backup channel (the slave). The backup
also checks the database every 30 seconds and changes to the schedule on the main
channel cause a schedule restore on the backup channel. This results in a delay of up to 30
seconds between schedule changes on the main and backup.
Master/slave operation relies on the status of a single router crosspoint (destination) to
determine which channel should act as the master. In the event of a failover, the backup
channel takes over the transmission of the scheduled programming.
Output Server 2 uses a leader/follower model for channel communication. This means the
main channel is the leader and its backup channel is the follower; in a simulcast system, the
simulcast channel and its backup channel are also followers. This is known as a
leader/follower network. When the iTX Desktop operator performs a manual control,
schedule change or changes an asset, the leader channel passes these changes on to its
followers and they respond instantaneously. This ensures the channels in the
leader/follower network are always in sync with each other, regardless of the number of
followers.