Transmission Modes And Delay; Switchboard Server; Crosslock - Comrex ACCESS MultiRack Product Manual

trAnsmIssIon modes And delAy

The MultiRack is a true codec, offering a full-duplex stereo encoder and decoder in each unit. When two-way
transmission is not required, the reverse channel may be disabled. The BRIC Normal technology incorporated
includes a jitter buffer manager that automatically balances delay and stability, dynamically increasing and
decreasing delay based on network performance. For networks where QoS is known, these parameters may be set
to maintain a consistent level of jitter buffer.
End-to-end coding delay in Linear modes is less than 25 ms. Delays when using FLAC and Opus modes are less than
30 ms. AAC modes incorporate around 100 ms total end-to-end delay while HE-AAC modes deliver around 220 ms.
In addition to coding delay, network propagation and jitter buffers will add delay to any IP link and are network
dependent.

swItchboArd serVer

Switchboard is a standard feature with MultiRack that allows the codec to "sync" with Comrex's cloud-based
traversal server. Switchboard facilitates connections between codecs without any knowledge of IP addresses on
either end of a link. Switchboard traversal server allows for monitoring presence and status information for all
Comrex codecs in a user's fleet, and assists with connections through routers and firewalls that might be difficult
otherwise. Because MultiRack incorporates five separate codec instances, each appears as an individual "codec"
within the Switchboard interface.

crosslock

MultiRack comes with a reliability feature called CrossLock VPN. Comrex codecs running 4.x-level firmware and
higher are compatible with CrossLock. This is a transport layer that adds the following features:
Error Correction (ARQ and FEC);
•
Dual Network support (Bonding and Redundancy modes);
•
Enhanced statistics and diagnostics.
•
Use of CrossLock is optional, and requires a Comrex codec running 4.x-level firmware on each end of the link.
CrossLock connections can be made via the Comrex Switchboard function (see previous section) or manually. For
manual connections, CrossLock requires extra settings to assure connections are only made within your known
group of codecs. 4.3-level firmware and higher also supports CrossLock when using very data-intensive algorithms
like Linear PCM and FLAC.
Users running 4.3-level firmware or higher are also able to utilize HotSwap, which is a feature of CrossLock that
allows users to designate one network in a CrossLock connection as primary and the other network as secondary
in order to increase flexibility and avoid potentially expensive data overage charges. MultiRack requires that if
engaged, HotSwap is active for all codec instances.
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