Comrex ACCESS MultiRack, Product Manual

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VIII.
MAKING CROSSLOCK CONNECTIONS ON MULTIRACK
Comrex first introduced CrossLock —its technology that creates an additional reliability layer to ensure quality
broadcast connections—with version 4.0 firmware in 2016. As an increasing majority of users updated their units
to CrossLock-capable firmware, connections made using CrossLock became the norm for Comrex codecs and are
considered standard in MultiRack and ACCESS Codec connections.
how crosslock works: A brIeF oVerVIew
CrossLock is available on MultiRack and older products running at least 4.x-level firmware. To understand how
CrossLock works, it’s helpful to first focus on non-CrossLock connections as shown in
Figure 37
.
FIgure 37 non-crosslock connectIon
Without CrossLock active, a codec will make BRIC Normal connections to MultiRack instance #1 on port 9000.
Instance #2 will connect on 9002 and instance #3 will connect on 9003. These are on the MultiRack side, and the
remote codecs will all use their default ports of 9000.
Alternatively, when CrossLock is used, it establishes a Virtual Private Network (VPN) between the hardware on both
the transmitting and receiving units before a connection is established. Using this VPN, codecs can transfer much
more information than is possible on Non-CrossLock legacy connections. This information includes network status,
packet loss statistics, error correction parameters, media statistic information to set encoder throttle rates, and
information required to establish links over multiple networks.
When enabled, the CrossLock VPN is created immediately when the first new connection is initiated, and remains
for a short time after the last connection ends. In order to use CrossLock, both units in the connection must be
running 4.x-level firmware or higher. CrossLock generally supports all algorithms that operate on 4.x-level firmware,
but only supports data-intensive algorithms (e.g. Linear PCM and FLAC) on units running 4.3-p4 firmware or higher.