Dancing with wolves: The COTS illusion - Military Embedded Systems

Dancing with wolves: The COTS illusion - Military Embedded Systems

Dancing with wolves: The COTS illusion - Military Embedded Systems

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Technology: Considering COTS costsDancing with wolves:The COTS illusionBy Ian ColvilleMilitary technology has come a long way since the days ofWilliam Wallace, who advised his troops before the first battleof Falkirk (on July 22, 1298), “I haif brocht ye to the ring, hop ifye can!” This translates in part as “dance as best you can.”These days, it is no longer a case of simply doing the best youcan – making do with what you’ve got in terms of skill, weapons,and equipment. Today’s military forces, from NATO and KFORto Iraq and ISAF, demand and get the latest in weapons and technologysystems. This is also true of communications, with forcesaround the world being better equipped than ever before in termsof Command, Control, Communications, Computers, and Intelligence(C4I).Enhanced Voice Processor (EVP) units are at the heart ofmany a military communications system. When sourcingCommercial Off-The-Shelf (COTS) enabling technologyfor these communications, there are always two keyrequirements that come to the fore: high density and lowcost per channel. Although COTS is perceived as a onesize-fits-allsolution, COTS products rarely meet militarysystems’ needs all by themselves; often add-on or enablingtechnologies must be implemented, too. Thus, companiesoffering COTS equipment for integration into militarystandard communications systems should be aware of thecontradiction in the real-world use of the term “off-theshelf.”Equally, systems suppliers looking to win defensecontracts – and needing to source components to fulfilltheir procurement specifications – should be preparedfor Non-Recurring Engineering (NRE) costs foradapting COTS products.Photo courtesy of the U.S. Air Force by Airman 1st Class Marc I. LaneKey to these communications systems are Enhanced VoiceProcessor units (see sidebar below), where interoperability andhigh functionality are required. However, it is clear that COTSproducts are unlikely to meet all such requirements themselves,without utilizing “add-on” functionality to provide increasedchannel density and low cost per channel, for example. Thus,systems suppliers desiring to win defense contracts should beprepared for NRE costs when adopting COTS products.Enabling technologiesIn light of modern military communications systems’ stringentrequirements for high levels of functionality, what is typicallymost important to a defense contractor is a high-density channelcount. However, most COTS products cannot meet such stringentrequirements on their own. But such requirements can be met viatechnology “add-ons” to the COTS hardware variant. Often thecore enabling technology has to be adapted, such as adding a newcodec, for example. And in providing high density, the contractorbenefits are twofold: gaining reduced cost and increased valueper channel.Enabling technology encompasses a wide range of hardwareand software building blocks for the development of highperformance,wired and wireless, IP- and TDM-based, enterpriseand telco communications solutions.Enhanced voice processor unitsA foundation of the communications element of C4I is theEnhanced Voice Processor (EVP) unit. This forms part of alarger gateway system between disparate networks andis an infrastructure designed to offer more than simplyone-to-one gateway functionality. The EVP within thismultifaceted gateway often includes voice, fax, data, andvideo functions.The multifunction gateway is typically used to providesecure communications at the rear of the battlespace,linking senior commanders back to HQ and forward tothe battle area. Systems allow interconnection on a backbonenetwork across a large geographical area as wellas the means to interconnect with single service and multinationalsystems.Designed to link all the elements of a Joint Force, systemscan be deployed in peacekeeping or offensive roles.In practice, systems are fully containerized and can beoperated in mounted or dismounted mode. They are alsodesigned to be scalable.© 2008 OpenSystems Publishing. Not Licensed for distribution. Visit opensystems-publishing.com/reprints for copyright permissions.

Gateway functionOne example of an essential CompactPCI gateway functionis to receive data from an ISDN channel as G.711A-law and to encode that data as MELPe, G.729d orG.711 A-law, then to packetize the data and encapsulateit within RTP/UDP/IP for transmission over an IP(Ethernet) interface. In the opposite direction, it recoversthe raw data from the RTP/UDP/IP packets, decodes thedata from MELPe, G.729d or G.711 A-law and transmitsit over an ISDN channel as G.711 A-law.The payload size and format of the RTP/UDP/IP packetsgenerated by the board in the case study met the rigorousdemands for data rates, latency (end-to-end delay),Mean Opinion Score (MOS) assessments, and throughputperformance stipulated by the client.MELPe RTP frames contain 22.5 ms of coded audio andare transmitted on 10 ms boundaries (DSPs run on a10 ms epoch) so as to average 1 packet every 22.5 ms(1 packet at 30, 50, 70, and 90 ms). G.729d frames willcontain 10 ms of coded audio and are transmitted every10 ms. Each MELPe frame and each G.729d frame aretransmitted in separate packets to minimize the end-toenddelay of the system. Delay is measured from receiptof each byte to the transmission of the same byte on thecorresponding interface and is under 100 ms for bothMELPe and G.729d.The board is capable of buffering up to N frames ofdata from the RTP/UDP/IP packets whilst the currentframe is being transmitted over the ISDN channel. Jitterbuffer size is software selectable and adaptive withinN = >0 frames.Dancing as best you can is no longer OK when it comes to militaryequipment, and companies offering COTS equipment to thissector will realize that “add-ons” must usually be implemented.Equally, systems suppliers looking to win defense contractsshould be prepared for those NRE costs.Ian Colville is a product manager atAculab, where his key role includessupport for the company’s global salesforce. Ian has spoken at a variety ofcustomer seminars on various subjectssince joining the company in 2000. He hasalso contributed technical documentation,including product literature and severalpublished articles. He has broad communications industryknowledge gained during a number of years employed in avariety of management roles by a major telecommunicationsmanufacturer. Ian’s industry experience spans marketing,sales, customer service, and project management. He can becontacted at ian.colville@aculab.com.Aculab+44-1908-273-800www.aculab.com© 2008 OpenSystems Publishing. Not Licensed for distribution. Visit opensystems-publishing.com/reprints for copyright permissions.

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