Vipersat satellite IP networks rely on satellite modems, consisting of a high-performance satellite modem with an imbedded IP Router, to provide the interface between LAN traffic and the satellite links that connect remote stations to the hub. Comtech Vipersat Networks provides cost effective satellite capacity management solutions optimizing broadband, two-way, multimedia communications over satellite networks. Comtech Vipersat Networks' solutions enhance satellite communication for a wide range of applications including video teleconferencing, distance learning, telemedicine, Internet content delivery, satellite news gathering, disaster recovery, as well as enterprise data networks.

Vipersat capacity management solution features include: 

• automated bandwidth allocation
• application, load, manual, & scheduled switching
• star and mesh topologies
• DVB and TDM outbound capable
• voice prioritization
• single hop on demand (SHOD)
• multi-transponder mode (MTM) 

Vipersat Satellite Modems

Satellite modems used in Comtech Vipersat IP based networks are provided by company, Comtech EF Data. Comtech EF Data has built a reputation on providing the most spectrally efficient, highest performance, very reliable, feature rich modems in the satellite industry.
 

Core Vipersat Modems
CDM-570/570L 10 Mbps Satellite Router
CDD-564/564L Quad Demodulator Router
CDD-562L Satellite Network Dual Demodulator Router
Switched SCPC Modems
CDM-600/600L Open Network Digital Satellite Modem
CDM-700 High Speed Modem
CDM-710 Broadcast Satellite Modem
SLM-5650 Satellite Modem
CIM-25 IP Enabled Monitor and Control
CRS-170A & CRS-180 1:1 Modem Redundancy Switches

Vipersat Selected Time-Division Multiple Access (STDMA)

Selected Time Division Multiple Access (STDMA) provides shared bandwidth access networks with a low initial hub cost as compared to traditional TDMA networks. This low cost, achieved by using a fast acquisition SCPC demodulator as the burst controller allows users with small to moderately sized networks to take advantage of demand driven space segment usage without a huge capital investment in hub hardware. STDMA is easily scalable to allow for network growth simply by adding burst controllers at the hub to accommodate additional groups of remote terminals.
 

The basic system is comprised of a Time Division Multiplexed (TDM) outbound which is shared by all remotes in the network. The return channels are Selective Time Division Multiple Access (STDMA). STDMA has two modes of slot allocation operation, fixed or dynamic. In fixed mode all remotes within a group are granted the same amount of transmission time in a cycle. When operated in dynamic mode, to take advantage of the bursty nature of IP traffic, the return channels are dynamically sized (in terms of transmission time in frame) based upon demand. All IP protocols are supported. Since under most circumstances it makes more sense to operate the network in dynamic mode, descriptions in this document address primarily dynamic mode operation. STDMA provides an extremely flexible platform supporting any type of data and streaming protocols.
 

Vipersat Single Hop on Demand (SHOD)

Single Hop On Demand (SHOD) switching technology does IP packet circuit switching at the application level. SHOD dynamic optimizes latency for low latency application (LLA) connections without the high costs of multiple carriers or one-to-one, multi-receiver links.
 

Single satellite hop technology provides less delay, ensures higher quality voice communications, and efficient use of the satellite space segment. Enhanced Quality of Service with one satellite hop gives near voice toll quality with minimum throughput delay. Increasing the QoS is as simple as adding strategically placed demodulator/routers, and enabling system policies within the VMS.

For normal data communications, the network operates in a star configuration where the remote terminal sends data packets to the hub via the shared inbound data transmissions. If the data is destined for another remote, the packet is retransmitted by the hub's outbound carrier to the destination remote. This method of re-broadcasting the packet creates a double hop doubling the circuit's latency. Normal data applications do not have a problem with the added latency. Low latency applications, however, cannot tolerate high latency connections, making double hop circuits unacceptable for these applications. 

Comtech Vipersat Networks' VMS software detects when a double-hop communication configuration exists for a LLA application and tunes the modem router to listen to the opposite remote's inbound carrier directly thereby completing a single hop circuit. 

SHOD dynamically provides a low latency satellite connection between remotes, thus ensuring that low LLA traffic is not assigned to double hop satellite circuits. At least one demodulator/router is required at each remote to support SHOD. Optionally more than one demodulator/router can be used at a remote if it is required to support simultaneous SHOD calls to more than one remote at a time. 
 

Vipersat Multi Transponder Mode (MTM)

Multi Transponder Mode (MTM) is a unique Vipersat feature which allows a satellite operator or service provider to allocate unused, but fragmented, portions of space segment across a satellite to a network. The allocated space segment can then be used for on-demand SCPC links.
 

By allowing the satellite operator to combine spectrum fragments into a usable group, the operator can make the combined group available to a user whose application requires the combined space segment bandwidth, but does not require that the bandwidth be contiguous. Note that the fragments must all have the same polarization in order for this technique to be effective.
 

Vipersat Features and Benefits
 

NetStar Technologies North American and international Vipersat Networks 2-Way Broadband Satellite services plans are customized on a per customer basis. To learn more about NetStar Technologies' Vipersat 2-Way Broadband Satellite Service Plans, call NetStar Technologies Sales at (361) 354-5468.