linkway s2 system description

LinkWay

SYSTEM DESCRIPTION

SDD00077_04 (August 23, 2007)

LinkWay System Description

Publication Information

Revision Number Date Released Comments

03 August 26, 2004 CO-016408

04 August 23, 2007 CO-041681

ViaSat, Inc.

Corporate Headquarters 6155 El Camino Real

Carlsbad, CA 92011-1699

Phone: (760) 476-2200

Fax: (760) 929-3941

Germantown, MD 20511 Seneca Meadows Parkway

Suite 200

Germantown, MD 20876

Phone: (240) 686-4400

Fax: (240) 686-4800

Duluth, GA 1725 Breckinridge Plaza

Duluth, GA 30096

Phone: (678) 924-2400

Fax: (678) 924-2480

SDD00077_04 (August 23, 2007) ViaSat Proprietary Page ii


TABLE OF CONTENTS LINKWAY SYSTEM DESCRIPTION.................................................................................................. 1 Section 1THE LINKWAY NETWORK ............................................................................................... 3

1.1 SUPPORT FOR A BROAD RANGE OF NETWORK TOPOLOGIES .............................. 4 1.2 NATIVE SUPPORT FOR PACKET-SWITCHING PROTOCOLS.................................... 6

IP SERVICE FEATURES.................................................................................................................... 6 FRAME RELAY SERVICE FEATURES ........................................................................................... 6 LEGACY PROTOCOL SUPPORT ..................................................................................................... 7

1.3 FLEXIBLE CONNECTIVITY AND SATELLITE ACCESS............................................... 7 1.4 EFFICIENT DEMAND-ASSIGNED BANDWIDTH MANAGEMENT ............................. 7 1.5 DIVERSE NETWORK APPLICATIONS.............................................................................. 7

VIRTUAL PRIVATE NETWORKS ................................................................................................... 8 PRIVATE CORPORATE NETWORKS ............................................................................................. 8 INTERNET SERVICE PROVIDERS.................................................................................................. 9 REAL-TIME DIGITAL VIDEO INTERNETWORKING .................................................................. 9 WIRELESS INTERCONNECTIVITY.............................................................................................. 10

1.6 LINKWAYS SUBSTANTIAL BENEFITS.......................................................................... 10 DRAWBACKS OF OTHER TDMA SYSTEMS .............................................................................. 10

Section 2LINKWAY NETWORK COMPONENTS ......................................................................... 13 2.1 THE LINKWAY INDOOR UNIT ......................................................................................... 13

THE LINKWAY MODEM................................................................................................................ 14 THE LINKWAY 2100 and LINKWAY.IP TERMINAL SPECIFICATIONS...................................... 16 THE LINKWAYS2 TERMINAL SPECIFICATIONS....................................................................... 19

2.2 THE LINKWAY OUTDOOR UNIT ..................................................................................... 21 THE LINKWAY RADIO FREQUENCY TERMINAL.................................................................... 21 THE LINKWAY ANTENNA............................................................................................................ 21

2.3 THE LINKWAY NETWORK CONTROL CENTER......................................................... 22 Section 3LINKWAY NETWORK OPERATIONS............................................................................ 23

3.1 LINKWAY TDMA ARCHITECTURE ................................................................................ 23 FRAME FORMAT AND HIERARCHY........................................................................................... 23 LINKWAYS2 DVB-S2 Operation...................................................................................................... 25 SINGLE-BEAM AND MULTIPLE-BEAM OPERATION .............................................................. 26 SITE AND TERMINAL ADDRESSING.......................................................................................... 26 ACQUISITION AND SYNCHRONIZATION ................................................................................. 26

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CLOCK MANAGEMENT................................................................................................................. 26

3.2 LINKWAY MANAGEMENT FEATURE............................................................................ 28 CONFIGURATION MANAGEMENT ............................................................................................. 28 ACQUISITION AND SYNCHRONIZATION CONTROL.............................................................. 28 BANDWIDTH MANAGEMENT ..................................................................................................... 29 FAULT PROTECTION ..................................................................................................................... 29 ACCOUNTING ................................................................................................................................. 29 PERFORMANCE AND ALARM MANAGEMENT........................................................................ 30 SECURITY MANAGEMENT........................................................................................................... 31

3.3 THE LINKWAY NETWORK MANAGEMENT WINDOWS........................................... 31 NMS ARCHITECTURE.................................................................................................................... 31 NMS WINDOW HIERARCHY ........................................................................................................ 32 NMS HOME PAGE ........................................................................................................................... 32 NETWORK STATUS........................................................................................................................ 33 BURST TIME PLAN......................................................................................................................... 34 SERVICE USAGE............................................................................................................................. 34 PERFORMANCE .............................................................................................................................. 35 DIAGNOSTIC TESTING.................................................................................................................. 35 ALARMS ........................................................................................................................................... 36 CONFIGURATION ........................................................................................................................... 36 SECURITY ........................................................................................................................................ 36 REMOTE ACCESS ........................................................................................................................... 37 SOFTWARE UPGRADES ................................................................................................................ 37

3.4 LINKWAY NETWORK PROTOCOLS AND SERVICES ................................................ 37 LINKWAYS IP SERVICE ............................................................................................................... 37 LINKWAYS FRAME RELAY SERVICE....................................................................................... 39

APPENDIX AGLOSSARY .................................................................................................................. 41 APPENDIX BLINKWAY RFT DESCRIPTION............................................................................... 57

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LIST OF EXHIBITS Exhibit 1- 1: A LinkWay Network ............................................................................................................ 4

Exhibit 1- 2: LinkWayThree Topologies, One Platform ..................................................................... 4

Exhibit 1- 3: Single-Beam Configuration.................................................................................................. 5

Exhibit 1- 4: Multiple-Beam Configuration ............................................................................................. 6

Exhibit 1- 5: Virtual Private Network Application.................................................................................. 8

Exhibit 1- 6: Multiple-Services Private Corporation Network............................................................... 8

Exhibit 1- 7: Internet Service Provider Network ..................................................................................... 9

Exhibit 1- 8: Real-Time Surveillance Network ........................................................................................ 9

Exhibit 1- 9: Wireless Interconnect Application.................................................................................... 10

Exhibit 2- 1: LinkWay Network .............................................................................................................. 13

Exhibit 2- 2: Spares Required for 100-Node Network........................................................................... 13

Exhibit 2- 3: LinkWay Modulator and Demodulator............................................................................ 14

Exhibit 2- 4: LinkWay Modem Performance Table .............................................................................. 15

Exhibit 2- 5: LinkWay 2100 Front Panel................................................................................................ 16

Exhibit 2- 6: LinkWay 2100 Back Panel................................................................................................. 16

Exhibit 2- 7: Terminal Characteristics ................................................................................................... 16

Exhibit 2- 8: Terrestrial Interface Options for 2100.............................................................................. 17

Exhibit 2- 9: Terrestrial Interface Options for LinkWay.IP ................................................................. 17

Exhibit 2- 10: Rear Panel FunctionsLinkWay 2100 and LinkWay.IP .............................................. 17

Exhibit 2-11: LinkWayS2 Front Panel ........................................................................................... 19 Exhibit 2-12: LinkWayS2 Back Panel....................................................................................................... 19

Exhibit 2-13: LinkWayS2 Terminal Characteristics............................................................................... 19

Exhibit 2-14: LinkWayS2 Terrestrial Interface Options ....................................................................... 20

Exhibit 2- 15: Rear Panel Functions LinkWayS2................................................................................ 20

Exhibit 2- 16: Redundant NCC Elements............................................................................................... 22

Exhibit 3- 1: TDMA Frame Hierarchy ................................................................................................... 23

Exhibit 3- 2: Multi-Carrier TDMA Frame Alignment.......................................................................... 24

Exhibit 3- 3: LinkWay Burst Types ........................................................................................................ 24

Exhibit 3- 4: General TDMA Burst Structure ....................................................................................... 24

Exhibit 3- 5: DVB-S2 Operation.............................................................................................................. 25

Exhibit 3- 6: Single- and Multiple-Beam Configurations...................................................................... 26

Exhibit 3- 7: Clock-Generation Algorithm............................................................................................. 27

Exhibit 3- 8: Data Rates and Packet Sizes .............................................................................................. 27

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Exhibit 3- 9: Redundant NCC Options ................................................................................................... 29

Exhibit 3- 10: NMS Architecture............................................................................................................. 32

Exhibit 3- 11: NMS Window Hierarchy ................................................................................................ 32

Exhibit 3- 12: NMS Home Page ............................................................................................................... 33

Exhibit 3- 13: Terminal List..................................................................................................................... 33

Exhibit 3- 14: Burst Time Plan ................................................................................................................ 34

Exhibit 3- 15: Traffic Information .......................................................................................................... 34

Exhibit 3- 16: Service History .................................................................................................................. 35

Exhibit 3- 17: Service Connections.......................................................................................................... 35

Exhibit 3- 18: Diagnostic Testing............................................................................................................. 35

Exhibit 3- 19: Configuration Windows ................................................................................................... 36

Exhibit 3- 20: Frame Relay Service Compliance ................................................................................... 40

Exhibit B- 1: LinkWay RFT Transmit Specifications ........................................................................... 57

Exhibit B- 2: LinkWay RFT Receive Specifications.............................................................................. 57

Exhibit B- 3: LinkWay RFT Operating Characteristics ....................................................................... 58

SDD00077_04 (August 23, 2007) ViaSat Proprietary Page vi


LINKWAY SYSTEM DESCRIPTION Satellite technology is often the preferred choice for a variety of telecommunications applications, such as:

Transaction-oriented or point-of-sale net-works.

IP multicasting and backbone connectivity. Television broadcast distribution. Basic voice and data communications

where the terrestrial infrastructure is either insufficient or nonexistent.

It is now possible to address wideband multimedia applications with new advances in VSAT technol-ogy, thereby seamlessly extending terrestrial infra-structure over large geographic areas. LinkWay provides native support for important telecommu-nications standards such as IP and Frame Relay.

LinkWay products provide a range of enterprise networking and telecommunications capabilities to fit almost every satellite and wireless network en-vironment. These products offer full-mesh, wide-band multi-service solutions on a single compre-hensive platform with multi-frequency TDMA sat-ellite air interface and packet transport services.

This document provides a high-level overview of the LinkWay network products to demonstrate how those products provide sensible solutions to chal-lenges in satellite networking. The three main sec-tions include:

Section 1The LinkWay Network explains fea-tures and capabilities of the LinkWay networking equipment across a variety of applications.

Section 2LinkWay Network Components de-scribes the physical elements of the LinkWay net-work sitethe indoor unit, the outdoor unit, and the Network Control Center hardware.

Section 3LinkWay Network Operations demon-strates how LinkWay uses TDMA to efficiently provide Frame Relay and Internet Protocol ser-vices.

This document also includes two appendices to aid in understanding the sophisticated utility of the LinkWay system in addressing satellite communi-cation solutions:

Appendix ATerms & Acronyms is a useful guide to the LinkWay terminology.

Appendix BLinkWay Radio Frequency Termi-nal Specifications describes the requirements for all LinkWay radio frequency terminals.

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Section 1THE LINKWAY NETWORK LinkWay is a multi-carrier, multi-rate, time-division multiple access (TDMA), VSAT-like (very small aperture terminal) platform that works with conventional satellites. It provides seamless full-mesh connectivity for flexible, on-demand broadband corporate networking applications. The LinkWay system can support hundreds of low-cost terminals with small antennas. Single-hop connec-tivity is a standard feature without the need for an expensive central hub station.

The current LinkWay products include:

LinkWay 2100This terminal fully supports Frame Relay and IP, and uses an integrated radio frequency terminal. LinkWay 2100 is more cost effective for remote VSAT applications. This ter-minal uses an L-band RFT interface in support of broadband applications that span multiple satellite transponders.

LinkWay.IPThis terminal fully supports IP. Packaged with smaller RFTs (2W, 4W, 5W) for star topologies, it is targeted for ISPs and corporate intranet applications. Unique IP software allows higher throughput IP applications.

LinkWayS2This terminal fully supports IP and frame relay. With an integral DVB-S2 receiver, LinkWayS2 supports both mesh and broadband star IP networks, in addition to mesh frame relay networks. LinkWayS2uses an L-band RFT inter-face in support of broadband applications that span multiple satellite transponders.

Using this family of LinkWay products, the system automatically allocates satellite bandwidth on an as needed, basis using dynamically measured traffic levels or on a fixed-assignment basis, if required.

In addition to efficient TDMA and automated bandwidth on demand (BoD), LinkWay eliminates the need for additional third-party networking equipment. This results in improved overall net-work reliability, lowered costs, and simplified in-tegration with terrestrial networks.

The LinkWay platform incorporates enhanced fea-tures providing a unique architecture that supports mesh, star, virtual star, and hybrid topologies. The products inherent flexibility allows individual VSAT locations to be configured as very low-cost remote terminals and economical high-capacity gateways. LinkWay broadband VSATs support multiple antenna and RF transceiver configurations with flexible carrier parameters that include vari-able bit-rates, power levels, and forward error cor-rection (FEC) settings for each carrier.

A LinkWay network has three basic parts:

The LinkWay terminal contains the satellite mo-dem and the necessary interfaces to provide Frame Relay and IP access.

The LinkWay outdoor unit (ODU) includes a ra-dio frequency terminal (RFT) and an antenna. The RFT consists of a solid state power amplifier (SSPA) and block up-converter (BUC). The termi-nal and ODU are connected by an interfacility link (IFL), which includes both a transmit (Tx) and a receive (Rx) cable. In addition, the LinkWay 2100, LinkWay.IP, and LinkWayS2 have the RFT inte-grated into the terminal, providing an L-band IF interface.

The heart of the LinkWay network is the Network Control Center (NCC), a Sun workstation that provides the management and control functions for all network terminals. The NCC is the platform for the LinkWay Network Management System (NMS) server. The NMS is the graphical user in-terfaceaccessed using a standard web browser, which the operator uses to configure the network and to request information from the NCC. The system supports NCC redundancy to increase net-work reliability.

Exhibit 1-1 illustrates four sites in a single net-work, with its NCC and NMS collocated with a LinkWay terminal and ODU combination, called a LinkWay site.



ey

NMSentsSTN

PDN

Broadband VSATs like LinkWay are idwideband multimedia applications encountemultinational corporations, carriers, servicviders, virtual private network operatorInternet service providers (ISPs). An effective broadband VSAT platform must provide the following capabilities in order to address todays diverse multimedia networking applications, which are discussed below:

Support for a broad range of network topologies (Section 1.1).

Native support for packet- and circuit-switching protocols (Sec-tion 1.2).

Flexible connectivity and satellite access (Section 1.3).

Efficient demand-assigned bandwidth management (Section 1.4).

1.1 SUPPORT FOR A BROAThe three most popular and regularly encotopologies include star (hub-and-spoke networks), mesh (any-to-any connectivity in one satellite hop), and virtual star (hybrid networks with multiple hub locations). These are illustrated in Exhibit 1-2:

A typical star network consists of a central hub location with many remotes supporting asymmetric outbound and inbound traffic requirements. Applications include applicationspecific interactive sys-tems in banking, retail, and other industrial sectors; PSTN network extensions; broadcast services; and Internet network extensions.

Page 4 of 58 LINKWAY

(NMS Server)

LINKWAY

LINKWAY

LINKWAY

LINKWAY

LINKWAY

Internet

LAN

Internet

FramRela

LINKWAYNETWORK

Multi-CarrierTDMA

Customer Premises

IP

IPLAN IP

NCC

To Cli

via Por

FrameRelay

IPIF

Gateway Site

Customer Premises

eal for red by e pro-s, and

Diverse network applications (Section 1.5).

Substantial benefits (Section 1.6). Office Park Site

Exhibit 1- 1: A LinkWay Network

D RANGE OF NETWORK TOPOLOGIES

LINKWAYLINKWAY

LINKWAYLINKWAY

Mesh LINKWAY

LINKWAYLINKWAY

LINKWAYLINKWAY

Star

LINKWAYLINKWAY

LINKWAYLINKWAY

Virtual Star(Hybrid)

Hub w/ 1 or moreLinkway Units

Exhibit 1- 2: LinkWayThree Topologies, One Platform

untered

ViaSat Proprietary SDD00077_04 (August 23, 2007)


NCC

NMS

NMS

MRT

TT3TT1

TT2

ODUODU

Site ASite B

AMRT

NCC

MRT Site

Exhibit 1- 3: Single-Beam Configuration

A mesh network consists of many terminals with one or two assigned to administer the network, no central hub location (although optional higher traf-fic gateways are possible), and support for any-to-any connectivity. Applications include telemedicine, corporate wide-area voice and data communications, LAN extensions and videoconferencing.

A virtual star or hybrid network consists of two or more hubs or gateways, and provides mesh con-nectivity between hubs, remote-to-multiple hub connectivity, and asymmetric data rates. Virtual star networks are essentially two-tiered topologies supporting high-traffic gateways with mesh con-nectivity to each other and small remote locations connected to the high-traffic gateways. Each tier requires links that provide fiber-like bit error ratio (BER) performance and asymmetric transmission rates. Typical applications include multinational corporate intranets, and service provider-operated virtual private networks.

LinkWay supports all three topologies, as well as:

Standard interfaces for packet-switched IP and frame relay networking applications.

Broadband data rates between 312 ksps and 5 Msps.

Demand-assigned allocation of bandwidth. LinkWay is a powerful platform, supporting high-rate, multiple protocol services for high-end appli-cations, and affordable (small-aperture) remote terminals operating over low-rate carriers as well. The system operates seamlessly because larger VSAT sites can carrier-hop between large and

small carriers as required by changing connectivity requirements.

In a single-beam configuration, as illustrated in Exhibit 1-3, the NCC links all of the traffic termi-nals in the network through the master reference terminal (MRT). (In Exhibit 1-3, the arrows be-tween the NCC and MRT, and the NCC and AMRT, indicate redundancy.) In all cases, each LinkWay terminal is capable of serving both as a reference and a traffic terminal. (The MRT and AMRT, however, must reside at the same site as the NCC.)

For instance, the MRT in Exhibit 1-3 controls all geographic locations in the network. The NCC is collocated with the MRT, and both can be backed up by using an alternate master reference terminal (AMRT) and another NCC in a redundant configu-ration. NCC and MRT redundancy offers a one-time switchover from the active unit to the backup unit. If the configuration is multiple-beam, as in Exhibit 1-4, there is also a supporting reference terminal (SRT) to control the traffic terminals as-sociated with each satellite beam the MRT cannot see. The SRT relays NCC commands from the MRT.



NCC

TT

SRTMRT

TT

Exhibit 1- 4: Multiple-Beam Configuration

1.2 NATIVE SUPPORT FOR PACKET-SWITCHING PROTOCOLS Broadband VSATs need to provide native support for the most important and widely used packet-switching protocols. This allows seamless transi-tions between the terrestrial and the satellite net-works and reduces or eliminates the need for addi-tional third-party networking equipment. The

LinkWay indoor unit supports IP, and Frame Relay packet-switching protocols (Section 3.4 provides more detail about LinkWay and these two proto-cols.) Legacy protocols, such as X-25, are sup-ported over LinkWay via a connected router using a standard LinkWay interface.

IP SERVICE FEATURES

LinkWay dynamically routes IP packets using RIP-1 and RIP-2, protocols, and supports unicast and multicast services, as well as static and default routing. LinkWay also supports RFC 1490 for IP access over Frame Relay. A native 10BaseT Ethernet connection (100BaseT in LinkWayS2) simplifies connectivity between the terrestrial net-working equipment and the LinkWay terminal.

The LinkWay system manages the routing table for IP and dynamically assigns bandwidth as needed. When a point-to-multi-point burst is allocated for a

data stream, all network nodes designated a con-trol group receive the burst assignment.

LinkWay allows multicast traffic bandwidth classi-fied as real-time connections to be assigned a higher priority than unicast traffic. Additionally, the operator can manage the available bandwidth by specifying a unicast allocation factor.

A variety of applications are possible with native IP support, including data multicasting, video streaming, voice over IP, and LAN-to-LAN and WAN-to-LAN connections.

FRAME RELAY SERVICE FEATURES

Each Frame Relay connection can be configured for a specific quality-of-service requirement. LinkWay allocates bandwidth as required with a combination of static and dynamic TDMA bursts to the satellite.

The LinkWay terminal provides EIA-530/RS-449/V.35 synchronous serial interfaces via cables

to frame relay routers, access devices, and switches.

LinkWay supports RFC-1490, which allows IP packets to be extracted from Frame Relay frames over the serial interface.



LEGACY PROTOCOL SUPPORT

LinkWay supports legacy protocols such as SDLC, X.25, and 2-wire/4-wire analog voice requirements by combining the IP or Frame Relay interfaces

with external routers or Frame Relay access de-vices.

1.3 FLEXIBLE CONNECTIVITY AND SATELLITE ACCESS Broadband multimedia applications require flexi-ble network architectures and a variety of satellite connectivity options. LinkWay provides a multi-carrier (up to 256 carriers), multi-data-rate TDMA platform that can operate on one or more satellite transponders and supports flexible connectivity for any networking requirement.

The TDMA burst modem within the VSAT plat-form operates at symbol rates between 312 ksps and 5 Msps depending on the LinkWay platform to address a diverse range of broadband multimedia content. The transmit and receive data rates can be

set independently for asymmetric transmission ap-plications, such as those typically encountered with IP applications. In addition, robust satellite links are possible with fiber-like BER performance since each carrier is assigned a convolutional-Viterbi inner code and a Reed-Solomon outer code.

LinkWay is operable on any international or re-gional geosynchronous satellite system. Common frequency bands include C- and Ku-band; the sys-tem will also operate on bent-pipe Ka-band satel-lite systems.

1.4 EFFICIENT DEMAND-ASSIGNED BANDWIDTH MANAGEMENT The LinkWay system runs a central bandwidth management program in order to efficiently use space segment and provide high levels of end-user data throughput.

The bandwidth management function performs both fixed bandwidth allocation and dynamic bandwidth allocation (bandwidth on demand):

Fixed bandwidth allocationCertain traffic cate-gories in Frame Relay require bandwidth to be al-located for the entire duration of the call. In these cases, bandwidth is allocated at call (or connec-tion) setup and remains allocated for the entire du-ration of the call. The bandwidth is de-allocated when the call ends (or the connection is torn down).

Dynamic bandwidth allocation (bandwidth on demand)Every LinkWay terminal runs a Band-width Reporter program that continuously moni-tors the incoming user traffic. The dynamic band-width allocation function collects the

reports from all traffic terminals and periodically runs an algorithm to distribute available bandwidth resources fairly and efficiently using three levels of fairness:

Outgoing FairnessAll connections originating from a particular terminal compete for the terminals total trans-mission capacity in a fair manner.

Incoming FairnessAll connections terminating at a particular terminal compete for the terminals total re-ceive capacity in a fair manner.

System FairnessAll connections in the entire network compete for the to-tal system capacity in a fair manner.

This algorithm provides bandwidth alloca-tion in response to changing incoming user traffic rates in a dynamic manner.

1.5 DIVERSE NETWORK APPLICATIONS LinkWay is particularly well-suited to the diverse topologies needed for todays wideband networks. Service providers and multinational corporations

can economically establish mesh, star, or virtual star networks using a single platform. This is im-portant for service providers, because:


Mesh networks support teleconferencing requirements.

Star networks support Internet access and data distribution.

Virtual star networks support corporate data intranets connecting remote offices to headquartersfactories, and MIS centers.

Popular broadband VSAT network examples, de

VIRTUAL PRIVATE NETWORKS

A virtual private network service provider, as illustrated in Exhibit 1-5, can establish virtual IP oFrame Relay connections over satellites usinbroadband terminals as entry points for client locations. The operators investment includes installinan NCC and leasing partial transponder space oany commercially available C- or Ku-band geostationary satellite. The operator takes advantagof the bursty nature of client traffic and demandassigned bandwidth to reuse the same transponderesources among a pool of clients. Because mosapplications do not require a full-time dedicatedata pipe, the network resources are made avaiable only for active applications.

The service provider bills customers for actual usage. Smaller customers (fewer than 10-20 sitescan interconnect branch or remote offices withoumajor investments in bandwidth and network management infrastructure. The service providermonthly bill to the end customer includes th

PRIVATE CORPORATE NETWORKS

Private multinational corporate networks en-counter a wide variety of applications, such as intranets and LAN extensions. Typical require-ments include file and image distribution, in-ventory control, video conferencing over FR and IP, e-mail, database backup, voice-over-digital PBXs, and voice over IP. Because Link-Way is configurable for any network topology, corporations can affordably provide broadband content to and from multiple locations. Exhibit 1-6 illustrates a multiple-services corporate network.

Page 8 of 58 ViaSaLinkWay System Description

-

-

-,

-

scribed below, include:

Virtual private networks. Private corporate networks. Internet service providers. Real-time digital video internetworking. Wireless interconnectivity. Disaster recovery.

-r g

equipment lease, installation expenses, and band-Frame Relay/IP

LINKWAY

Company C

LINKWAY

LINKWAY

LINKWAY

LINKWAY

Company C

Company C

Company B

Company BCompany A

Company A

Company B

Company A

Exhibit 1- 5: Virtual Private Network Application

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-) t -s e

width use.

Voice/FaxPABX

PSTN

LANVideo

PABX

Router

Video

PSTN

LAN

LAN

TCP/IP

PABXLINKWAY

LINKWAY

LINKWAY

Exhibit 1- 6: Multiple-Services Private Corporation Network

t Proprietary SDD00077_04 (August 23, 2007)


INTERNET SERVICE PROVIDERS

LINKW AY

LINKWAY

LINKW AY

Server

PSTN

LINKWAY

LINKWAY

ContentProvider

4 Mbps250 Kbps

Gateway

y ISP Servicey POP-to-POP Connectivity

(E-mail, Voice, LAN)

POP #1

POP#25

POP #50

Exhibit 1- 7: Internet Service Provider Network

Because LinkWay networks support asymmetric traffic applications, they are ideal for Internet ser-vice providers (ISPs). An asymmetric circuit con-sists of high-rate and low-rate connections. Exhibit 1-7 illustrates an ISP application using multiple high-rate connections and several low-rate connec-tions. The high-rate connection broadcasts IP con-tent to all point-of-presence (POP) locations, each of which serves a large community of dial-in users. Low-rate connections are shared among POPs to transport requests to the content-provider. The low-rate connections can also be used for adminis-trative traffic (such as e-mail, technical support, reports, request for spare equipment, and voice

applications) among the individual POPs in a sin-gle satellite hop.

REAL-TIME DIGITAL VIDEO INTER-NETWORKING

Video teleconferencing, telemedicine, and video surveillance are growing applications for broad-band VSATs, and all require transporting real-time digital video over IP. For example, the digital video surveillance network shown in Exhibit 1-8 comprises several distinct user groups. These are combined to form one network of many remote

surveillance sites, each monitoring highway traffic.

Each remote surveillance site broadcasts digital video signals to gateway locations using IP multi-casting at a user-specified data rate. The data rates and the specific user groups can be programmed for video transmissions. All other network com-munications, such as group-to-group connectivity,

can be implemented with IP unicasting on de-mand.

Satellite Dish

Sensor

Video

AsymmetricCommunications

Exhibit 1- 8 Real-Time Surveillance Network



WIRELESS INTERCONNECTIVITY

LinkWay can accommodate cellular or base station connectivity over the satellite by using VoIP or VoFR call routing, and high-speed TDMA carriers. Typical base stations require T1/E1 connections to the central office on demand. A broadband VSAT facilitates the rapid extension of a countrys wire-less telephony infrastructure to smaller cities and rural areas that either lack E1/T1 infrastructure or need to augment their E1/T1 capacity. A wireless interconnection application is illustrated in Exhibit 1-9.

MTS

BS BS

LINKWAY

PSTN

LINKWAY LINKWAY

Exhibit 1- 9: Wireless Interconnect Application

1.6 LINKWAYS SUBSTANTIAL BENEFITS Networks based on LinkWay products have clear advantages over the existing VSAT systems in the market. The benefits of LinkWay networks in-clude:

LinkWay networks use a hub-less architec-ture.

Multi-protocol support enables easy migra-tion to emerging applications.

LinkWay networks support asymmetric traffic requirements.

LinkWay networks support both full-mesh and star topologies on a single platform in a single hop.

LinkWays unique patented dynamic band-width-on-demand (BoD) algorithm dis-tributes network bandwidth among many sites effectively and efficiently as needed.

LinkWay networks support wideband traf-fic on demand.

In situations where the wideband content is pro-vided from various destinations, LinkWay net-works support multiple gateway network architec-tures without a hub.

LinkWay networks support multimedia applica-tions through standard native, Frame Relay, and IP interfaces. This enables LinkWay terminals to in-terface seamlessly with existing terrestrial net-works and to improve overall network reliability by minimizing the need for additional third-party devices.

LinkWay networks offer flexible satellite carrier definition configuration to support variance in the

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t-

DRAWBACKS OF OTHER TDMA SYSTEM

As compared with LinkWay, other TDMA systems have substantial drawbacks:

Other TDMA systems cannot support high-speed IP-unicast, IP-multicast, and frame relay applica-tions on a single platform, which drastically limits future migration choices.

e d

Page 10 of 58 ViaSat Prtransponder and remote antenna. This includes thability to define a transponder frequency offset, known and defined, to enhance the tracking Rcapability for the terminals. In addition, the abilito define signal power level on carrier basis supports smaller and larger antennas in the same nework.

S

The multi-board design of the indoor units in thessystems makes maintenance and sparing costly andecreases reliability and efficiency. oprietary SDD00077_04 (August 23, 2007)


The other TDMA systems have limited carrier-hopping capability for the asymmetric topologies and applications required by Internet service pro-viders.

Limited modulation and coding capabilities of these systems combine to increase their bandwidth consumption, space segment cost, and station size.

The fixed burst of these systems result in frag-mented space segment, lower bandwidth effi-ciency, and longer response time.

Because these systems do not support cross-strapped transponders and inclined orbit satellites, they have limited connectivity and growth poten-tial.

The bandwidth-on-demand capabilities of these systems are inefficient.

These systems support multi-carrier-hopping re-quirements among no more than a few carriers, which severely limits true wideband networking applications.

These systems require a separate network man-agement system for every eight to ten carriers, which results in bandwidth fragmentation and complicated operation.

Other TDMA systems have limited carrier throughputs.



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Section 2LINKWAY NETWORK COMPONENTS A LinkWay network consists of LinkWay sites managed by a Network Control Center (NCC) workstation at one of the sites. The LinkWay hardware includes:

LINKWAY

EthernetHub

PC with ApplicationSoftware

BUC SSPA

AMPController

IF Input from LNB

L-Band IF Outputto ODU

10 B

ase

T

SSPA 48VDC

WR75

Tx IFLTNC (10MHz)(12/15vdc)

LNB

WR75 vdc)

Rx IFL L-Band (950)-1640 MHz)15 vdc "F" Female

Exhibit 2- 1: LinkWay Network

The terminalthe upper left portion of Exhibit 2-1the speci-fications for which are described in Section 2.1 below.

The outdoor unit, or ODU, consists of the radio frequency terminal (RFT) and antenna. Their specifications are listed in Section 2.2 and Appendices B and C.

The NCC includes a Sun workstation and a PC. Their specifications are detailed in Section 2.3.

LinkWay is an extremely reliable system. The ta-ble in Exhibit 2-2 shows the mean time between

failures (MTBF) for the network elements and, consequently, how many spares are required in a 100-node LinkWay network.

Exhibit 2- 2: SPARES REQUIRED FOR 100-NODE NETWORK

Replaceable Units MTBF

(Hours) Number of

Units Number of

Spares*

Remote Terminal

Remote ODU

Single NCC

Terrestrial Interface Adapter (TIA)

*Based on an accumulatedpercent and assuming fa

2.1 THE LINKWAY INDOThe LinkWay terminals are housed rack-mountable packages with L-bandlinks (IFL) to radio frequency termioperating in C-, Ku-, or Ka-band.

The modulator output and demodulatobe set as indicated in Exhibit 2-3. To oformance, LinkWay performs automsetting of the internal front-end attenu

SDD00077_04 (August 23, 2007) 70,000 100 6

50,000 100 7

40,000 1 1

100,000 100 5

Poisson distribution model using an availability of 99.9 iled units are replaced in 40 days.

OR UNIT in compact

interfacility nals (RFTs)

r input can

on the satellite system and geographic location, the LinkWay terminal can be deployed with a variety of RFTs, ranging from 1.2-m/2-Watt Ku-band units to 3.8-m/60-Watt C-band units.

The LinkWay contains a TDMA burst modem,

ptimize per-atic coarse ator. Based

TDMA frame controller, and terrestrial traffic in-terfaces.

Up to three physical interfaces can be activated on

ViaSat Proprietary Page 13 of 58


the LinkWay 2100 unitthe Internet Protocol (IP) interface is built-in, and the customer can select up to two Frame Relay (V.35, RS-449, RS-530), inter-faces as optional interfaces. The LinkWay.IP ter-minal supports only IP. The LinkWayS2 has built-in interfaces for IP and FR, and can support two op-tional plug-in interface cards.

Exhibit 2- 3: LinkWay Modulator and Demodulator

Modulator Out-put

Demodula-tor Input

LinkWay 2100 & LinkWay.IP

-5 to 25 dBm in dBm steps

-35 to 75 dBm

LinkWayS2 0 to -30 dBm in dBm steps

-35 to -75 dBm

THE LINKWAY MODEM

LinkWay incorporates a multi-carrier, multi-rate, time-division multiple access (TDMA) modem. Each carrier in the LinkWay network can be con-figured with different speeds and forward error correction (FEC) rates. Larger carriers increase terminal throughput, but also increase outdoor unit (ODU) power and size requirements. Smaller car-riers limit connectivity to star or partial-mesh to-pologies, but also reduce capital investment per remote terminal. With the exception of the ODU size, the system administrator can modify the con-figuration at any time.

As many as 256 carriers can be supported in a LinkWay network. Initially, however, only one carrier is required for each network. Additional carriers can be added as the network traffic in-creases. All carriers in a transponder can be auto-matically shared among the users on demand. As-signment of terminals to carriers is performed dy-namically by the Network Control Center (NCC) collocated with one terminal.

LinkWay 2100, LinkWay.IP supports the following modem TDMA symbol rates:

312.5 ksps 625 ksps 1.25 Msps 2.5 Msps 5 Msps

LinkWayS2 supports the following TDMA symbol rates:

312.5 ksps 625 ksps 1.25 Msps 2.5 Msps 5 Msps (optional)

This multi-rate feature accommodates various net-work applications and antenna sizes. Regardless of the selected modulation and coding scheme, carrier bandwidth occupancy remains constant. Modula-tion and coding selection affect power require-ments, as well as user information throughput. Therefore, it is common to configure the traffic bursts with QPSK modulation to increase user in-formation throughput. The NCC automatically configures modulation and coding for each burst. The transmit and receive side of the modem can operate and hop asymmetrically and independ-ently. This feature is ideal for Internet Service Pro-vider (ISP) point-of presence (POP) applications, or corporate networks with asymmetric traffic ar-chitecture.

The LinkWayS2, in addition to incor-porating a multi-carrier, multi-rate, time-division multiple access (TDMA) modem, incorporates an integrated DVB-S2 receiver which provides high-speed download capability from a central site, as well as interoperability with ViaSat s LinkStar system.

LinkWay-S2s DVB-S2 receiver uses EN 302 307 compliant coding, so that operators may use LinkWay-S2 with a standard EN 302 307 DVB-S2 modu-lator and IP encapsulator, or with Vi-aSats LinkStar-S2 hub.

The LinkWay Modem Performance Table in Ex-hibit 2-4 provides a performance summary.



LinkWay2100, LinkWay.IP, and LinkWayS2 use Viterbi FEC with concatenated Reed Solomon (236, 216) coding. The FEC is configurable by carrier.

Turbo product code is optional for the LinkWayS2.

Modulation for the LinkWay 2100 and Link-Way.IP is QPSK.

The LinkWayS2 uses QPSK modulation in the standard configuration. 8PSK modulation is op-tional for the LinkWayS2.

The LinkWay modem has a rolloff factor of 0.3; the carrier spacing factor is 1 + (roll-off) = 1.3. Thus, the allocated bandwidth is the symbol rate x 1.3.

The IF looped Eb/No performance for BER = 10-8 is listed in the following table. Additional margin (typically 0.4 to 0.8 dB) above these values should be allocated to account for RF looped performance. The LinkWayS2 operates up to 2.5 Msps as stan-dard. An option is available for operation up to 5.0 Msps.

Exhibit 2-4: LINKWAY MODEM PERFORMANCE TABLE

Carrier Symbol

Rate

FEC Satellite Link Bit

Rate

Eb/No

Ksps Kbps dB5000 1/2 4590.2 4.65000 2/3 6120.2 5.25000 3/4 6885.2 6.15000 7/8 8032.8 7.82500 1/2 2295.1 4.62500 2/3 3060.1 5.22500 3/4 3442.6 6.12500 7/8 4016.4 7.81250 1/2 1147.5 4.61250 2/3 1530.1 5.21250 3/4 1721.3 6.11250 7/8 2008.2 7.8625 1/2 573.8 4.9625 2/3 765.0 5.5625 3/4 860.7 6.4625 7/8 1004.1 8.1

312.5 1/2 286.9 5.2312.5 2/3 382.5 5.8312.5 3/4 430.3 6.7312.5 7/8 502.0 8.4



THE LINKWAY 2100 and LINKWAY.IP TERMINAL SPECIFICATIONS

The tables and figures below detail the LinkWay 2100 and IP terminal specifications:

Exhibit 2- 5: LinkWay 2100 Front Panel

Exhibit 2-5 displays the LinkWay 2100 front panel.

Exhibit 2-6 displays the LinkWay 2100 back panel with optional TIAs installed.

Exhibit 2-7 details the LinkWay terminals ba-sic characteristics.

Exhibit 2-8 details LinkWays terrestrial inter-face options for LinkWay 2100.

Exhibit 2-9 details LinkWays terrestrial inter-face options for LinkWay.IP.

Exhibit 2-10 displays rear panel functions for the LinkWay 2100 and LinkWay.IP.

Exhibit 2- 6: LinkWay 2100 Back Panel

Exhibit 2- 7: TERMINAL CHARACTERISTICS

LinkWay 2100 and LinkWay.IP Dimensions 8.9 cm/3.5 (h) x 43.8 cm/17.25 (w) x 36.8.4 cm/14.5 (d) and mount-

able in a standard 19 rack Weight 5 kg/11 lbs Temperature Operating: 0 to +40C Storage: 0 to +70 C Relative Humidity Operating: 0 to 95% Storage: 0 to 95% Power supply 50/60 Hz; auto-range: 100 VAC to 240 VAC Power consumption 80VA without ODU Fuse 3 Amps at 264 V Certification CE, UL, and FCC



Exhibit 2- 8: TERRESTRIAL INTERFACE OPTIONS FOR 2100 Ethernet Serial Synchronous

Protocols

IP: RIP-1, RIP-2

Frame Relay, RFC 1490

Maximum Data Rate 3 Mbps 2 Mbps

Clock Rate 10 Mbps 64 to 2,048 kbps

Standards

RFC 1058

RFC 1490

RFC 1112

EIA/TIA-449

EIA/TIA-530

V.35

Physical Interface 10BaseT, IEEE 802.3

RS-449/RS-422

RS-530/RS-422

V.35

Connectors 6-pin RJ-45 26-pin SCSI RS-449 37-pin, D-type RS-530 25-pin, D-type V.35

Exhibit 2- 9: TERRESTRIAL INTERFACE OPTIONS FOR LINKWAY.IP

LinkWay.IP Ethernet

Protocols IP, RIP-1, RIP-2

Maximum Data Rate 3 Mbps duplex

Clock Rate 10 Mbps

Standards RFC 1058, RFC 1112

Physical Interface 10BaseT, IEEE 802.3

Connectors 8-pin RJ-45



Exhibit 2- 10: REAR PANEL FUNCTIONSLINKWAY 2100 and LINKWAY.IP

Function Rear Panel Label Specification

Power supply 50/60 Hz Auto-range100 VAC to 240 VAC

ODU IF connec-tions

IF INPUT TO ODU

IF OUTPUT FROM ODU

Tx950-1525 MHz (L band), 50 Ohm, Type N female

Rx950-1750 MHz (L band), 75 Ohm, Type F female

TVRO950-1750MHz (L band), 75 Ohm, Type F female

Craft Interface CONSOLE 4-Pin RJ-11 JackRJ-11 to DB25 converter cable supplied. Supports RS-232, external mo-dems.

LAN Interface 10BaseT 8-Pin RJ-45 JackIEEE 802.3 compatible. 10BaseT physical interface

Network Clock In-terface (10 MHz)

EXT REF 50 BNC1V peak-to-peak sinusoidal clock waveform input

Interface 1 No Label

Left Slot

Supports 1 LinkWay Interface Card,Frame Relay, (not available on LinkWay.IP)


Right Slot

Supports 1 LinkWay Interface Card, Frame Relay, (not available on LinkWay.IP)



THE LINKWAYS2 TERMINAL SPECIFICATIONS

The tables and figures below detail the Link-WayS2 terminal specifications:

Exhibit 2- 11: LinkWayS2 Front Panel

Exhibit 2-11 displays the LinkWayS2 front pan-el.

Exhibit 2-12 displays the LinkWayS2 back panel.

Exhibit 2-13 details the LinkWayS2 terminals basic characteristics.

Exhibit 2-14 details terrestrial interface options for LinkWayS2.

Exhibit 2-15 displays rear panel functions for the LinkWayS2 .

Tx Out, 75 , Type-F Jack

10 MHz Ref., 50 , BNC Jack

10/100 MHz Ethernet, RJ-45

RS-232 Console Port, RJ-11

Form C AlarmAuxiliary ODU Power

Rx In, 75 , Type-F Jack

USB Port

Ground Stud

IEC Power Connector w/ Switch

Expansion Interface 2

Expansion Interface 1

Frame Relay, 26 pin SCSI-2

Exhibit 2-12: LINKWAYS2 BACK PANEL

Exhibit 2- 13: LINKWAYS2 TERMINAL CHARACTERISTICS

LinkWayS2P Dimensions 4.4 cm/1.73 (h) x 43.1 cm/17 (w) x 39.6 cm/15.6 (d) and mountable in

a standard 19 rack Weight 3.4 kg/7.5 lbs Temperature Operating: 0 to +50C Storage: 0 to +70 C Relative Humidity Operating: 0 to 95% Storage: 0 to 95% Power supply 50/60 Hz; auto-range: 100 VAC to 240 VAC Power consumption 55 VA without ODU Fuse 3 Amps at 264 V Certification CE, UL, and FCC



Exhibit 2- 14: LINKWAYS2TERRESTRIAL INTERFACE OPTIONS

Ethernet Serial Synchronous

Protocols

IP: RIP-1, RIP-2 Frame Relay, RFC 1490

Maximum Data Rate

Variable 2.048 Mbps

Clock Rate 10/100BT, FDX 64 to 2,048 kbps

Standards

RFC 1058

RFC 1490

RFC 1112

EIA/TIA-449

EIA/TIA-530

V.35

Physical Interface

10/100BaseT, IEEE 802.3

RS-449/RS-422

RS-530/RS-422

V.35

Connectors 6-pin RJ-45 26-pin SCSI

Exhibit 2- 15: REAR PANEL FUNCTIONSLINKWAYS2

Function Rear Panel Label Specification

Power supply 50/60 Hz Auto-range100 VAC to 240 VAC

ODU IF connec-tions

IF INPUT TO ODU

IF OUTPUT FROM ODU

Tx950-1750 MHz (L band), 75 Ohm, Type F female

Rx950-1750 MHz (L band), 75 Ohm, Type F female

Craft Interface CONSOLE 4-Pin RJ-11 JackRJ-11 to DB25 converter cable supplied. Supports RS-232, external mo-dems.

LAN Interface 10BaseT

100BaseT (s2)

8-Pin RJ-45 JackIEEE 802.3 compatible. 10/100BaseT physical interface

Multi-Function BNC Connector

EXT REF 50 BNCProgrammable 10MHz clock refer-ence input/output; SORF/SOTF trigger


Left Slot

Supports 1 LinkWayS2 Interface Card PMC Expansion Slot


Right Slot

Supports 1 LinkWayS2 Interface Card, PMC Expansion Slot



2.2 THE LINKWAY OUTDOOR UNIT A LinkWay network will function efficiently with a variety of radio frequency terminals (RFTs) and antennas, including customer-owned equipment.

The specifications for the LinkWay RFT are briefly described in The LinkWay Radio Fre-quency Terminal section below and detailed in Appendix B.

The specifications for the LinkWay antenna are briefly described in The LinkWay Antenna section below.

THE LINKWAY RADIO FREQUENCY TERMINAL

The Ku-Band radio frequency terminals (RFTs) for LinkWay 2100, LinkWay.IP, and LinkWayS2 can be configured for 2-, 4-, 8-, 16-, or 25-Watt operation and the C-Band transceivers for 5-, 10-, 20-, 40-, and 60-Watt operation:

In LinkWay 2100, LinkWay.IP, and LinkWayS2 the RFT interface is integrated into the terminal for a substantial cost savings to the customer.

A monitoring feature verifies system status and isolates faults in the field-replaceable unit.

The RFT, housed in a weatherized enclosure, can be either mounted on or adjacent to the antenna feed support and has the following circuitry:

Transmit and receive RF converters. Transmit RF power amplifier. Summary alarm circuitry.

Configurations employ a standard BUC integrated with an SSPA or booster amplifier. The SSPA is a

galium arsenide field effect transistor (GaAs FET) based for highly linear operation. Both the gain and the detected power are calibrated over tem-perature and frequency. Control data for these functions are stored in lookup tables.

All ViaSat-supplied LNBs (C and Ku-Band) are phase-locked (PLL) and externally referenced to a 10 MHz signal. The LinkWay terminal generates the 10 MHz reference signal. The externally locked PLL LNBs ensure proper acquisition of TDMA bursts at all carrier symbol rates. Internally locked LNBs cannot ensure successful burst acquisition and should not be used.

Appendix B describes the RFT in some detailThe LinkWays RFT dimensions are detailed in Exhibit B-1 and the transmit and receive specifica-tions in Exhibits B-2 and B-3, respectively. Ex-hibit B-4 details the LinkWay RFTs operating characteristics.

THE LINKWAY ANTENNA

The LinkWay network is typically supplied with a 1.2-m, 1.8-m, 2.4-m, or 3.8-m antenna system type approved by EUTELSAT or INTELSAT. Link-Way can also be used with most customer-supplied antennas, as well as specially configured antennas.

1.2-m Antenna SystemFor both C-band and Ku-band. The latter includes the EU-TELSAT-type approved option of long-focal-length.

1.8-m Antenna SystemFor both C-band and Ku-band.

1.8-m Antenna SystemINTELSAT-type-approved for C-band and EUTEL-SAT-type-approved for Ku-band.

2.4-m Antenna SystemFor both C-band and Ku-band.

2.4-m Antenna SystemINTELSAT-type-approved for C-band and EUTEL-SAT-type-approved for Ku-band.

3.8-m Antenna SystemFor linear and circular C-band and for Ku-band.



2.3 THE LINKWAY NETWORK CONTROL CENTER The NCC performs overall management and con-trol of the LinkWay network. Network configura-tion is defined at the NCC and automatically dis-tributed to the terminals. The NCC can be config-ured in a redundant or non-redundant architecture, either at the same site or at geographically sepa-rated sites.

A single LinkWay traffic terminal is always desig-nated as Master Reference Terminal (MRT) and connected to the NCC using an Ethernet interface. The NCC then communicates with other LinkWay

terminals through the MRT via the satellite link. Operators located remotely can log on to the NCC using PCs (or Macs) with Web browsers. This re-mote clientthe Network Management System (NMS)is the operators interface to the network configuration and status screens. The NCC is a hosted on a Sun workstation. Exhibit 2-16 illus-trates a redundant NCC setup. A non-redundant situation uses a single Sun workstation, external modem, and universal power supply.

PC Computer

Sun WorkstationNCC

External ModemUniversalPower Supply

LINKWAY

LINKWAY

Sun WorkstationAssociated

NCC

External ModemUniversalPower Supply

Linkway MRT

Linkway AMRT

Network Control Center Components

(Locally Redundant)

PSTN

PSTN

EthernetSwitch

Exhibit 2- 16: Redundant NCC Elements



Section 3LINKWAY NETWORK OPERATIONS This final section ties together four elements in order to complete this high-level description of the LinkWay network:

Section 3.1 describes LinkWays TDMA architec-ture.

Section 3.2 describes LinkWay network manage-ment features.

Section 3.3 illustrates LinkWay network manage-ment windows.

Section 3.4 details LinkWay protocols and ser-vices.

3.1 LINKWAY TDMA ARCHITECTURE In order to access the space segment, LinkWay uses time division multiple access (TDMA) tech-niques. Frame Format and Hierarchy describes the frame format and hierarchy that LinkWay uses.

LinkWay can function in either Single-Beam or Multiple-Beam Operation, and can efficiently ac-commodate very large or small networks. The

manner in which LinkWay handles all these alter-natives is described in Site and Terminal Address-ing, while LinkWays acquisition and synchroniza-tion techniques are outlined in Acquisition and Synchronization. LinkWays clock management is described in Clock Management. Packet and Cir-cuit Transport Services outlines LinkWay packet and circuit transport services.

FRAME FORMAT AND HIERARCHY

Reference

SOF Frame Period EOF

SOMF

SOCF

Frame 1 Frame 2 Frame 3 Frame nFrame n-1

MF 2MF 1 MF 3 MF m-1 MF m

Control Frame Period

Multiframe Period

Exhibit 3- 1: TDMA Frame Hierarchy

LinkWay employs a hierarchical frame structure composed of frames, multiframes, and control frames as illustrated in Exhibit 3-1.

TDMA Frame Structure A TDMA frame is the basic periodic interval of time during which a terminal transmits or receives one or more bursts. LinkWay frame duration has a nominal value of 27 ms. Every frame boundary is delineated by a start-of-frame (SOF) instanta point relative to the position of the beginning of the first symbol of the reference burst in the frame. Each reference burst frame is identified numerically by a frame identifier.

As Exhibit 3-2 illustrates, each carrier in a multi-carrier operation transports a TDMA frame that is time aligned with all other carriers frames on SOF, start of multiframe (SOMF), and start of control frame (SOCF). A multiframe is the duration of N consecutive frames. The nominal value for N is 8. Multiframe boundaries are deline-ated by an (SOMF) instant encoded in the frame identifier.

LinkWay transmits and receives bursts on speci-

fied frames of the multiframe.

A control frame is the duration of M consecutive frames. The nominal value for M is 128. Control frame boundaries are delineated by an SOCF in-stant encoded in the frame identifier. LinkWay transmits and receives bursts on specified frames of the control frame.



Exhibit 3- 3: LinkWay BURST TYPES

Burst Type

Transmitting Terminal

Type Purpose

Reference (RB)

Reference Conveys outbound NCC signaling

Conveys timing feedback data to traffic terminals

Establishes receive timing Signaling (SB)

Traffic Conveys inbound traffic terminal signaling

Acquisition (AB)

Traffic Conveys transmit response message

Used to acquire traffic ter-minal transmit timing

Control (CB)

Traffic Conveys traffic terminal status report

Used to maintain traffic ter-minal Transmit timing

Traffic (TB)

Reference and Traffic

Conveys circuit and packet data

SOF SOMF SOCF

SOF SOMF SOCF

Carrier 1

Carrier 2

Carrier N

Exhibit 3- 2: Multi-Carrier TDMA Frame

Alignment

TDMA Burst Structure In LinkWay, the burst is the high-level unit of transmission, with multiple burst types providing efficient space-segment use. Exhibit 3-3 itemizes the burst types.

Bursts are composed of several fields. Exhibit 3-4 displays the burst structure and its relationship to frames and carriers. The burst structure has the following elements:

The carrier and bit timing recovery (CBTR) data pattern aids receiving modems in obtaining carrier and symbol clock acquisition. The CBTR consists of 128 consecutive symbols of alternating binary 1's and 0's. The CBTR beginning defines the burst position in the frame.

The unique word (UW) data pattern aids receiving modems in locating the first symbol of the first channel in the data field. The UW consists of 48 consecutive symbols. Reference bursts have a UW that differs from non-reference bursts.

RB SB CB AB TB TB

TDMA Frame

Carrier 1

TB

RBSB TB TB TBTB TB

CBTR UW Channel 0 Channel 1 Channel C GuardBurst

Data Bits

Circuit Packet

Packet 1 RSChannel RS Packet 2 Packet P

Carrier 2

Exhibit 3- 4: General TDMA Burst Structure (Channel structure for illustrative purposes onlycircuit and packet

data are never on the same burst)



Channel structureBursts can carry either 64-kbps circuit or packet data within their channels. Packet bursts may have up to 8 channels. Circuit bursts are either 64-kbps data or 8-kbps com-pressed voice. Circuit-data channels are simply filled with encoded data. Packet-data channels con-tain many packets of varying length. To facilitate error detection and depending on correction, Reed-

Solomon check bytes are included in both circuit- and packet-data channels.

Guard timeEvery burst is defined in the frame with guard space to prevent transmit burst timing errors from resulting in burst overlap and loss of data. Each terminals bursts are controlled in order to limit timing variations at the satellite to 1/2 guard time.

LINKWAYS2 DVB-S2 Operation

LinkWayS2 incorporates a built-in DVB-S2 re-ceiver, in addition to its TDMA modulator and TDMA demodulator, which shares a common receive input with the TDMA demodulator. The LinkWayS2 integrated DVB-S2 receiver/decoder can receive a broadband IP data stream from a DVB-S2 hub, providing efficient broadband star connectivity to a central data source while si-multaneously providing full-mesh capability.

LinkWayS2, for example, can support band-width- intensive IP applications such as stream-ing video over the DVB-S2 link while support-ing intrinsically mesh applications such as VoIP over mesh TDMA. Also, LinkWayS2 is interop-erable with ViaSats LinkStarS2 system, provid-ing a universal, flexible networking solution.

Exhibit 3- 5: DVB-S2 Operation in LinkWayS2

DVB-S2 HUB

LinkWay-S2 combines full-mesh networking with broad-band DVB-S2 downlink in one integrated package.

LinkWayS2

LinkWayS2

LinkWayS2



SINGLE-BEAM AND MULTIPLE-BEAM OPERATION

LinkWay is designed for both single-beam and multiple-beam operation. Exhibit 3-6 depicts a simple example of each. As shown in the figure, in the single-beam case, all terminals have transmit and receive access to all carriers assigned to the system. The MRT directly supports all terminals. In the multiple-beam case, terminals have transmit access to one set of carriers and receive access to another. The MRT supports terminals in Beam 2 and the supporting reference terminal (SRT) sup-ports traffic terminals in Beam 1.

BEAM 1 BEAM 2

CARRIERS

SRT

TT1NCC/NMS TT2

MRT

MULTIPLE-BEAM CONFIGURATION

NCC/NMS

CARRIERS

SINGLE-BEAM CONFIGURATION

TT1

TT2

MRT

Exhibit 3- 6: Single- and Multiple-Beam Configurations

SITE AND TERMINAL ADDRESSING

The LinkWay site and terminal addressing scheme efficiently accommodates a wide range of network configurations and is designed to support thou-sands of sites. Each site can have multiple termi-nals. In addition to individual terminals, the system can also address sites and groups of sites. This ad-dressing scheme provides for very large networks without penalizing small ones.

Although only one terminal will be designated as the MRT in a LinkWay network, each LinkWay terminal can perform as both reference and traffic terminal. The NCC dynamically assigns the refer-ence terminal function, which simplifies configura-tion, maintenance, and upgrade procedures, while increasing the systems flexibility.

ACQUISITION AND SYNCHRONIZATION

Because the Doppler motion of the satellite and oscillator drift normally cause timing variations, maintaining synchronization is critical to the error-free operation of any network. LinkWay terminals use TDMA acquisition and synchronization proce-dures to establish and maintain burst synchroniza-tion.

LinkWay procedures enable new terminals to join the network quickly. Typically, a terminal will en-

ter the network within 30 seconds of power up. A network of 100 terminals ready to enter the net-work typically completes entry within 10 minutes. As the network grows, or if faster entry is desired, multiple acquisition bursts can be defined. Termi-nals can enter the network at approximately the rate of 10 per minute per acquisition burst.

CLOCK MANAGEMENT

To minimize timing error in the system, each LinkWay terminal automatically monitors and ad-justs its direct digital synthesizer (DDS) to match that of its MRT or supporting reference terminal.

To further minimize timing error, an industry-standard, highly accurate external clock source can be connected to the reference terminal as an op-tion. The reference terminals DDS tracks the ex-ternal clock in frequency and phase, while all other

terminals continue to track the reference terminals DDS. This is a cost-effective method for highly accurate timing throughout the system. Without an external clock source, the DDS is accurate to 1 part in 107. An accurate external clock typically raises accuracy to 1 part in 1011.



LinkWay terminal interfaces accept data timed to the terrestrial data-receive clock and use the terres-trial data-receive clock in transmitting data to the terrestrial network

In order to generate accurate clocks in its distrib-uted TDMA system, LinkWay uses a distributed

algorithm that requires an accurate clock source at the TDMA terminal. (See Exhibit 3-7.) The local clocks of all other terminals are phase locked to the reference terminals clock.

Clock Correction

ru rd tutd

Satellite

GPSDiscOSC

Ref Clock(20 MHz)

FreqCounter(error)

TX/RXcorrections

Clock Algorithm

Reference Terminal

VCXO

TX/RXTiming

Terr/ModemClock Ref(doppler free) Freq

Counter(error)

TX/RXcorrections

Clock Algorithm

Traffic Terminal

VCXO

TX/RXTiming

Terr/ModemClock Ref(doppler free)

Exhibit 3- 7: Clock-Generation Algorithm



3.2 LINKWAY MANAGEMENT FEATURE The NCC is the central control for the entire LinkWay network. Hosted on a Sun workstation, the NCC software runs as a single application process and performs the following functions:

Configuration Management. Acquisition and Synchronization Control. Bandwidth Management. Fault Management. Accounting. Performance and Alarm Management. Security Management.

CONFIGURATION MANAGEMENT

The NCC stores all configuration data for the en-tire LinkWay network. Each configuration data file is similar to a file (or a relation) in a regular data-base management system. The NCC software reads the configuration data into RAM at startup; this RAM copy is used during network operation. The files are written to only when configuration data changesfor example, additions and deletions to existing data.

The NCC Configuration Management function interfaces with the Java-based NMS to add, delete, or modify the configuration data.

At terminal startupand upon any configuration changesthe NCC downloads configuration data. Should the configuration data change, the NCC sends modifications to the terminals.

ACQUISITION AND SYNCHRONIZATION CONTROL

The NCC controls acquisition and synchronization of the LinkWay network. Upon startup, the NCC establishes contact with the MRT (and SRT) and commands it to initiate reference station acquisi-tion and synchronization. The reference station starts transmitting the reference burst. In loopback-beam operation, the reference station hears its own transmission in order to achieve synchronization. In multiple-beam operation, the MRT hears the SRTs reference burst and vice-versa in order to achieve synchronization.

After the MRT (and SRT) achieves synchroniza-tion, the NCC initiates the acquisition and syn-chronization procedure for traffic terminals in the system, using the reference terminals as a relay to

communicate with the terminals. Traffic terminals are commanded to transmit a sequence of acquisi-tion bursts, whose arrival time and frequency are measured by the MRT. Using these measurements, the NCC sends back frequency and timing correc-tions to the traffic terminals, and they are then ready to carry user traffic.

After initial acquisition and synchronization, traffic terminals periodically transmit control bursts, whose timing and frequency are measured by the MRT or SRT. Using these measurements, the NCC sends back further frequency and timing correc-tions to the terminals. These corrections keep the terminals synchronized with satellite movements.



BANDWIDTH MANAGEMENT

Please see the earlier section, 1.4 EFFI-CIENT DEMAND-ASSIGNED BANDWIDTH

MANAGEMENT for more detail.

FAULT PROTECTION

LinkWay has three levels of fault protection:

System faults are handled through the NMS and its alarm functions. A: Non-redundant B: Locally redundant

C: Geographically redundant

Satellite

Sun Station

LINKWAY 2000 LINKWAY 2000

LINKWAY 2000

Sun Station

LINKWAY 2000

Sun Station Sun Station

Sun Station

Exhibit 3- 8: Redundant NCC Options

Terminal faults are minimized using redun-dant-terminal operation for terrestrial interfaces (see, for illustration, Exhibit 1-3).

Network faults are minimized in two ways: (a) redundant NCC configuration and (b) re-dundant MRT configuration.

The NCC can be configured as either locally or geographically redundant (see Exhibit 3-8 for several options). In a geographically redundant configuration, the NCC functions are passed to a standby NCC on a backup Sun workstation located at a different site.

In redundant MRT cases, the NCC monitors its connection to the MRT and AMRT. When it detects that the MRT is not responding, the NCC automatically switches the reference station func-tions to the alternate master reference terminal. This switch-over mechanism allows continuous

operation of the TDMA network, even when the MRT fails.

The LinkWay NCC and MRT redundancy scheme offers a single rollover from active to passive unit, ensuring no unscheduled disruption in network synchronization.

ACCOUNTING

The NCC accounting function generates account-ing reports for all user IP and frame relay connec-tions A resource utilization record is written at connection startup and shutdown.

The accounting management subsystems architec-ture consists of an accounting manager module at each terminal and the NCC communicating over the reliable packet transport protocol.

The NCC accounting manager receives accounting records from all terminal accounting managers and stores them in accounting files. There is one ac-counting file per service per accounting session, with each accounting session being a 24-hour pe-riod.

Each call has a unique call ID that appears in all accounting records written for it. This ID holds across terminal and NCC resets. Intermediate re-cords are generated at the end of every accounting session for calls lasting more than a day. If a ter-minal fails, appropriate records are generated for ongoing calls. Call beginning and end times are noted in Greenwich Mean Time (GMT), although accounting sessions may end at midnight GMT or local time.

For more detail, refer to document item # 1025156, LinkWay Accounting Features available on the ViaSat Extranet Web site.



PERFORMANCE AND ALARM MANAGEMENT

The performance management function is useful in monitoring a terminals health and for diagnosing problems. It enables the NMS operator to view transmit and receive burst data and to collect per-formance dataBER and link statistics and IP trafficfrom individual terminals. The NMS op-erator can also assess service statistics from Frame Relay, or IP connections. The NCC collects data for each burst containing the selected connection. Data are gathered for channel access control transmissions to and from the satellite, and for the terrestrial interfaces by link and connection.

The operator can collect performance statistics from individual terminals for monitoring the health of a particular terminal and for diagnosing prob-lems. Various fault alarms are collected from the terminals and distributed to the NMS for display on the operator screen. Some of the important pa-rameters monitored are:

Statistics for each receive burst. Accumulated statistics for each transmit

burst.

Accumulated statistics on a per destination basis (e.g., number of packets sent, allo-cated packet bandwidth, average number of bytes per sec).

Packets dropped at a node. Packets forwarded at a node. Throughput on the link. The NCC monitors the following informa-

tion for each terminal:

Terminal ID. Terminal typeMRT, SRT, or TT. StateUp/down Number of times the terminal has ac-

quired.

Number of acquisition commands sent to the terminal.

Number of status request messages sent to the terminal.

Number of status response messages re-ceived from the terminal.

Number of reports received from the ter-minal.

The following statistics are maintained on a per-port basis:

Current port statusUp or down. Loopback condition detectedYes or no. Data packets received for transmission. Data bytes received for transmission. Data packets sent to the user. Data bytes sent to the user. Number of signaling packets received. Number of status inquiry packets received. Number of status packets received. Number of signaling packets sent. Number of status inquiry packets sent. Number of status packets sent. User procedure signaling errors, e.g., mes-

sage loss, sequence number, invalid header.

Number of times user procedures declared the channel inactive.

Network procedure signaling errors (mes-sage loss, sequence number, invalid header etc.).

Number of times network procedures de-clared the channel inactive.

The operator can send diagnostic commands to a terminal or the NCC. The major diagnostic func-tions that can be executed via the NMS are:

Verifying TDMA performance by displaying burst statistics. Along with the number of data segments transmitted on each burst, the system reports burst ID and the number of detects, misses, Viterbi cor-rections, and cyclic redundancy check (CRC) er-rors.



Verifying Frame Relay performance through the Frame Relay connection control process in a ter-minal, which handles making and breaking con-nections within the LinkWay network.

Verifying IP performance by providing IP statis-tics for each terminal in the network with IP traffic.

The alarm management function collects informa-tion regarding various terrestrial interface alarms from the terminals and distributes it to the NMS for display on the operators screen. The system

displays information for all active alarms in the system and identifies failures at the interface card level. Alarms are sent only for equipment or inter-face failure. Service performance or BER levels will not trigger any alarms

In addition, whenever a terminal goes down, or the NMS loses its connection to the NCC, the NMS sounds a continuous beep alarm, and displays the Beep Alarm window. The NMS operator must ac-knowledge the alarm to turn off the beep.

SECURITY MANAGEMENT

The NCC maintains NMS operator login and password information as part of the configuration data and uses this information to authenticate op-erators trying to log into the system. The system has three levels of security:

Full AccessAllows the NMS operator to view and modify all configurable databases.

Read-Only AccessAllows the NMS operator to view only the configuration data. This privilege can be further specified to limit access to configu-ration data of one or a set of terminals.

Restricted AccessAllows the NMS operator to read only portions of the network that have been specified.

3.3 THE LINKWAY NETWORK MANAGEMENT WINDOWS The LinkWay NMS is a web-based, platform-independent Java application that provides central network management functionality. Any number of NMS client systems, running on any platform us-ing any Java-capable Web browser can retrieve

data from and deliver information to the NCC. This creates a significant cost advantage over other network management systems requiring a specific platform.

NMS ARCHITECTURE

The NMS-NCC interface follows the general architecture in Exhibit 3-9. The NMS consists of a web browser application that opens an HTTP connection to the web server running on the NCC host machine. The NCC machine is a Sun

workstation running a UNIX application. Run-ning independent from the NCCbut on this same Sun workstationis an off-the-shelf web server. The web server manages incoming HTTP socket connection requests.



Sun

SPARCsta tion

Sun

SPARCstatio nNCC (WWW)

HTTP NMS consists of aplatform-independentweb-browser applicaiton

NCC includes a web server that provides anNMS applet via an http URL (descriptor file)

to any and all web client requests

Exhibit 3- 9: NMS Architecture

NMS WINDOW HIERARCHY

Exhibit 3-10 illustrates the hierarchy of NMS windows.

IP ISDN FrameRelay ATM

Configuration

NMS Home Page

Performance Monitoring

Alarms

Network Configuration Site Configuration

ODUConfiguration

ServiceConfiguration

Accounting/Billing

Call Managemnt

Search NetworkMap

SystemLog

Network Status

Diagnostic Testing

TerminalConfiguration

Service Connections

Exhibit 3- 10: NMS Window Hierarchy

NMS HOME PAGE

A map showing the status of the LinkWay network automatically appears as the NMS Home Page. (See Exhibit 3-11.) From this page, the operator can explore the LinkWay network. The home page enables the NMS operator to view sites and termi-nals geographically and readily obtain status and configuration information. When a detailed map is available, zoom selection displays a larger map of

the area and shows the terminal icons. Map graph-ics are enhanced for each customers locations.

The home page map shows the location of sites in the network and updates the associated icons when terminal status changes:

Green indicates a terminal is up.

Red indicates a terminal is down.



Exhibit 3- 11: NMS Home Page

Black indicates the site has no configured termi-nals.

Yellow indicates (in multi-terminal sites) some terminals are up and some are down.

Operators can also navigate to site, terminal, and protocol configuration screens after selecting a particular site or terminal on the map.

NETWORK STATUS

Clicking Network Status brings up detailed in-formation on terminal status and network events. For example, the Terminal List tab lists all cur-rently configured terminals, as well as the cur-rent status and alarm state of each. (See Exhibit 3-12.)

Exhibit 3- 12: Terminal List

The Event Log tab, on the other hand, lists all major network events, each of which is time and date stamped. Initially, the system retrieves the last 10 log entries; the operator can request more entries as desired.



BURST TIME PLAN

The Burst Time Plan window displays the cur-rent burst allocation for each type of burst. (See Exhibit 3-13.) The system dynamically updates this display as bandwidth is allocated, enabling the operator to graphically view the bandwidth-on-demand feature in real timethe bursts ap-pear and disappear as the NCC monitors the LinkWay network and allocates and de-allocates bandwidth based on user traffic requirements

.

Exhibit 3- 13: Burst Time Plan

SERVICE USAGE

Detailed accounting and billing information is maintained on the NCC Sun workstation. These resource utilization records (or call detail records) are stored in an easily im-ported format.

Exhibit 3- 14: Traffic Information

The operator can generate graphic representations of traffic information for calls through any site. (See Exhibit 3-14.) Usage can be displayed by day, week, month or other specified time interval. The operator uses the Service History button on the home page to bring up lists of all service connections. (See Exhibit 3-15.)



Exhibit 3- 15: Service History

PERFORMANCE

In a manner similar to service history, the operator can view detailed information on active connec-tions, physical interfaces, and TDMA transmit and receive statistics. The Performance button brings up a list of all service connections. (See Exhibit 3-16.) Selecting any terminal or interface and press-ing The Get Stats button displays details about any current call for service to or from any site.

Exhibit 3- 16: Service ConnectionsDIAGNOSTIC TESTING

Diagnostic testing enables the operator to execute and view the results of diagnostic commands. (See Exhibit 3-17.) These commands can be executed on the NCC or from any terminal.

Exhibit 3- 17: Diagnostic Testing



ALARMS

The operator can view and analyze all the systems active terrestrial interface alarms with the click of a button. In addition, the system issues an audible

beep alarm and displays a message window should a terminal go down or the NMS lose connection with the NCC.

CONFIGURATION

Beginning with the windows illustrated in Exhibit 3-18, the operator configures all network, site, and

service parameters for the network.

Exhibit 3- 18: Configuration Windows

SECURITY

The LinkWay NMS implements several levels of security. The first is enforced by the web server. Clients requesting access are checked for valid IP addresses and domain names. When a valid client address has been identified, the web server then prompts for operator authentication. After authenticating the operators identity, the web server downloads the HTML files and app-let bytecode to run on the local client machine.

The second level of security is implemented at the applet level. The bytecode is compressed and signed with a certificatea password-protected, encrypted data file that ensures the identity of the operator. This certificate allows each NMS setup to independently allow or disallow various operations to the NMS.

Finally, once the applet is downloaded and run-ning, it opens a TCP socket connection to the NCC. The applet then prompts the operator for a LinkWay user ID and password, and the NCC verifies.

Afte

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