Automatic switching, General, To appendix – Comtech EF Data CDM-570/570L Vipersat User Manual

Page 119: B, “automatic switching, Appendix b, “automatic switching,” in thi, Utomatic, Witching

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Appendix B - Automatic Switching

B-1

A

P P E N D I X

A

UTOMATIC

S

WITCHING

General

Automatic switching is a feature of the VMS that allows dynamically changing

the network configuration in response to changes in either network traffic loads

(Load switching), traffic type (Application switching), or Type of Service (ToS

switching) detecting stamped packets with Diffserv values. Entry Channel

Mode switching is also covered.
These switching types are presented in the following material which uses CDM-

570/L, SLM-5650A, and Series800 modem units for purposes of illustration.

For simplicity, these units shall be referred to as modem/routers.
The basic signal topology in a Vipersat network is TDM (Time Division Multi-

plex) outbound and Vipersat’s proprietary STDMA (Selected Time Division

Multiple Access) inbound. The STDMA slots can have their duration and band-

width allotments varied, tailoring bandwidth allocation to meet the bursty traffic

load of a typical data network.
When required, a network is switched from STDMA to SCPC. SCPC band-

width is allocated from a bandwidth pool by the VMS to meet QoS or other

requirements for the duration of a connection. When the SCPC connection is no

longer required, the bandwidth is returned to the pool for use by another client.
This basic structure gives the VMS-controlled network its flexible, automated

network utilization and optimization capability.
The VMS has the intelligence to interpret the constantly changing statistics

gathered by the Vipersat modem/routers and uses this data to issue commands

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