Stdma; Single Hop On Demand - Comtech EF Data Vipersat 564L User Manual

P r o d u c t D e s c r i p t io n
In a typical Vipersat application used in conjunction with CDM-570/570L
modems, the CDD-56X demodulators are drawn from a pool for assignment to a
connection-oriented link.
Traffic inbounds from remotes can be switched manually or automatically,
application or load triggered, or scheduled, from shared STDMA (burst) mode
to a dedicated SCPC connection. The VMS automatically assigns a free demod-
ulator at the Hub to a desired remote inbound, completely eliminating manual
intervention. At remote sites, the CDD-56X simplifies Single Hop On Demand
(SHOD) applications with direct remote-to-remote connections that do away
with double-hops. Once the session is completed, the remote is automatically
reverted back to its home state.
In addition, the CDD-56X simplifies Single Hop On Demand (SHOD) applica-
tions with direct remote-to-remote connections that do away with double-hops.
The result is an economical and flexible network with bandwidth shared and
directed where it is needed for any mix of IP voice, video, and data traffic.

STDMA

The addition of STDMA capability to a Vipersat network allows multiple termi-
nals to share the same satellite resources that would be dedicated to a single
terminal in an SCPC configuration. This means that more terminals can be
added to the network with minimal additional cost in either satellite bandwidth
or Hub Terminal hardware.
Vipersat STDMA thus provides a low cost solution for medium to large sized
networks with generally moderate bandwidth requirements, while at the same
time providing all the features of the existing Vipersat systems, including the
availability of a switched pool of SCPC channels for occasional high bandwidth
traffic such as video conferences and large file transfers. Each STDMA
upstream channel from the remote terminals to the Hub uses an STDMA frame
operating at an aggregate data rate of from 16 kbps to 9.98 Mbps and can
support up to hundreds of remote terminals with multiple burst channel
inbounds.
Configured as a Hub terminal, the CDD-564/564L provides one demod for
receiving an upstream STDMA channel from the remotes, and three demods for
receiving three SCPC channels.

Single Hop On Demand

The CDD-56X is ideal for mesh applications such as Vipersat's Single Hop On
Demand (SHOD). With the CDD-56X, SHOD (meshed) circuits are easily and
economically established between remotes. SHOD provides significant and
dynamic connectivity between latency connections without suffering the high
costs associated with multiple carriers and/or 1-to-1 multi-receiver links.
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