108 JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010B. Integrated CPE Functional DecompositionFigure 2 shows the Open CPE architecture that is<strong>in</strong>tended to fulfill the requirements as listed above and tosupport multiple broadband access technologies andtelephony protocol standards. It is composed <strong>of</strong> a CPEController Module (CCM), LAN Interface Modules(LIM), and WAN Interface Modules (WIM). The CCMconsists <strong>of</strong> a CPE Controller, Flash, ROM, and RAM thatconta<strong>in</strong> a Real-Time Operat<strong>in</strong>g System (RTOS) ands<strong>of</strong>tware to implement telephony call control, networkmanagement, and service logic functions, as well as thirdpartyapplications. The CCM may also <strong>in</strong>clude a DigitalSignal<strong>in</strong>g Processor (DSP) to implement media stream<strong>in</strong>gprocess<strong>in</strong>g functions, such as vocoder, echo cancellation,tone generation and detection. The CCM can be reconfiguredto support different protocols or telephonystandards through s<strong>of</strong>tware download<strong>in</strong>g.Figure 2: Open CPE architectureWIM and LIM conta<strong>in</strong> plug-<strong>in</strong>s to support variousWAN and LAN <strong>in</strong>terfaces. WIM may consist <strong>of</strong> aWireless Modem , a Cable Modem, a DSL Modem, aFiber Modem, and a 10 Gigabit Ethernet module thatprovide <strong>in</strong>terfaces to the broadband access network. LIMmay <strong>in</strong>clude <strong>in</strong>terfaces to analog phones. There are twobuses responsible for the distribution <strong>of</strong> user data, realtimevoice stream<strong>in</strong>g, control signal<strong>in</strong>g, and themanagement data between the CCM Controller and theWIM/LIM. The <strong>in</strong>terface specification should meet therequirements <strong>of</strong> transport<strong>in</strong>g real-time and non-real-timedata. The open CPE architecture as described above isderived from the abstraction <strong>of</strong> multiple CPE platformsthat may use various broadband access technologies andstandards. The goal <strong>of</strong> the abstraction is to f<strong>in</strong>d out whatfunctions are common to all CPEs and therefore shouldbe implemented <strong>in</strong> CCM, and what functions are <strong>in</strong>terfacedependent. and therefore are more appropriatelyimplemented <strong>in</strong> plug-<strong>in</strong> modules. Figure 3 gives anexample <strong>of</strong> the CPE functional decomposition. It depictsthe protocol stacks <strong>of</strong> I-CPE support<strong>in</strong>g cable, xDSL, and10 Gigabit Ethernet broadband <strong>in</strong>terfaces to provide voiceand data convergence services.Figure 3: I-CPE protocol stackThe Cable CPE is <strong>in</strong>tended to provide VoIP services.It uses Network-based Call Signal<strong>in</strong>g (NCS) [4] as thesignal<strong>in</strong>g protocol to perform telephony call controlfunctions, while encapsulat<strong>in</strong>g the voice stream<strong>in</strong>g data <strong>in</strong>the Real-Time Protocol (RTP) packets to be sent to theCable Modem Term<strong>in</strong>ation System (CMTS). xDSL CPEprovides VoIP and Voice over AAL2 (ATM AdaptationLayer type 2) Loop Emulation Services (LES) [5]. It usesH.248 [7] and Channel Associated Signal<strong>in</strong>g (CAS)protocols to implement telephony call control functionsfor VoIP and VoAAL2, respectively. The voice stream<strong>in</strong>gdata are encapsulated <strong>in</strong> either RTP or AAL2 packets tobe sent to the DSL Access Multiplex (DSLAM). In thisexample, the Ethernet CPE acts as a SIP client to provideVoIP services. SIP is used to establish, modify, andterm<strong>in</strong>ate multi-media sessions and calls [10]. The voicestream<strong>in</strong>g is encapsulated <strong>in</strong> the RTP packets transmitt<strong>in</strong>gto the term<strong>in</strong>at<strong>in</strong>g party via the User Datagram Protocol(UDP) connection.In the Time Division Multiplex (TDM) networks,only call control and management functions areimplemented by s<strong>of</strong>tware <strong>in</strong> the processor, leav<strong>in</strong>g thevoice process<strong>in</strong>g to be handled by the hardware, because<strong>of</strong> the latency concern.However, the trend toward packet telephony, alongwith the advancement and <strong>in</strong>creas<strong>in</strong>g performance <strong>of</strong>processors <strong>in</strong> recent years, has made it possible for, andeven demanded that, voice stream<strong>in</strong>g be processed bys<strong>of</strong>tware. Thus, as Figure 3 <strong>in</strong>dicates, it makes good senseto locate the CCM-WIM <strong>in</strong>terface between Layer 2 andLayer 3 <strong>of</strong> the protocol stack. The CCM conta<strong>in</strong>ss<strong>of</strong>tware to implement voice process<strong>in</strong>g, the signal<strong>in</strong>gprotocol, and management functions. WIM shouldimplement Physical layer (PHY), Medium AccessControl (MAC), Logical L<strong>in</strong>k Control (LLC),Asynchronous Transfer Mode (ATM), and ATM.Adaptation Layer (AAL) functions that are closelycoupled with each broadband access <strong>in</strong>terface.IV. CONCLUSIONThe explosion <strong>of</strong> the Internet along with regulationand technology changes are reshap<strong>in</strong>g telecommunicationnetworks <strong>in</strong> many ways. The <strong>in</strong>dustry is mov<strong>in</strong>g towardthe convergence <strong>of</strong> PSTN and the Internet. The© 2010 ACADEMY PUBLISHER
JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 109converged network, the NGN, will operate <strong>in</strong> a verysimilar way to the Internet topology <strong>in</strong> which central<strong>of</strong>fice switches are decomposed <strong>in</strong>to distributed systemsthat are based on the S<strong>of</strong>tswitch model. As a result, theNGN will no longer provide transport services betweentelephone equipment (as PSTN previously did), but willprovide personalized multi-media services. Thisconvergence <strong>of</strong> voice and Internet data traffic also callsfor the deployment <strong>of</strong> I-CPE to provide <strong>in</strong>tegratedservices. However, the ever-chang<strong>in</strong>g network standardsand compet<strong>in</strong>g technologies not only confuse carriers, butalso prevent them from committ<strong>in</strong>g to massive CPEdeployment, because they are afraid that the CPE justdeployed will have to be replaced <strong>in</strong> a few years.Hardware replacement is very common <strong>in</strong> the PC andcellular phone bus<strong>in</strong>ess when new standards ortechnologies are <strong>in</strong>troduced, but it presents a big threat tothe wirel<strong>in</strong>e broadband bus<strong>in</strong>ess because CPEdeployment is such a daunt<strong>in</strong>g task that it cannot becompleted easily. In this paper, I proposed an open CPEarchitecture to solve the CPE deployment dilemma. Thearchitecture is very flexible and can support multipleWAN/LAN technologies and IP Telephony standards. Italso <strong>in</strong>cludes a common API to allow users to customizeor even create new services and third-party developers tocreate new applications and services. The open CPEarchitecture will allow CPE vendors to lower costs andreduce time-to-market, and most importantly enableservice providers to provide many value-added servicesthat promise great potential for generat<strong>in</strong>g additionalrevenueREFERENCES[1] C. A. Elder<strong>in</strong>g, “Customer Premises Equipment forResidential Broadband Gateway,” IEEE CommunicationMagaz<strong>in</strong>e, , pp. 114-121, June 1997.[2] S. Moyer and A. Umar, “The Impact <strong>of</strong> NetworkConvergence on Telecommunications S<strong>of</strong>tware,” IEEECommunication Magaz<strong>in</strong>e, pp. 78-84, January 2001[3] C. Low, “Integrat<strong>in</strong>g Communication Services,” IEEECommunication Magaz<strong>in</strong>e, pp. 164-169, June 1997.[4] “PacketCable Network-based Call Signal<strong>in</strong>g ProtocolSpecification,” Pkt-SP-EC-MGCP-101-990312, Cable Lab,3/12/1999.[5] “Voice and Multimedia over ATM–Loop Emulation ServiceUs<strong>in</strong>g AAL2,” af-vmoa-145.000, ATM Forum, July 2000.[6] J. Chou, “The migration <strong>of</strong> LES to the Next GenerationNetwork based on H.248,” ATM Forum, atm00-164, SanFrancisco, May 2000[7] F. Cuervo, N. Greene, A. Rayhan, C. Huitema, B. Rosen,and J. Segers. “Megaco Protocol Version 1.0,” IETFRFC3015, November 2000.[8] J. Lennox, H. Schulzr<strong>in</strong>ne, “Call Process<strong>in</strong>g LanguageFramework and Requirements,” IETF RFC2824, May 2000.[9] J. Rosenberg, J. Lennox, H. Schulzr<strong>in</strong>ne, “Programm<strong>in</strong>gInternet Telephony Services,” IEEE Internet Comput<strong>in</strong>g,May-June 1999, pp. 63-72.[10] M. Handley, H. Schulzr<strong>in</strong>ne, E. Schooler, and J.Rosenberg, “SIP: Session Initiation Protocol,” IETF,RFC2543, March 1999.[11] “OpenCable,” http://www.opencable.com, Cable Labs.[12] J. Lennox, H. Schulzr<strong>in</strong>ne, J. Rosenberg, “CommonGateway Interface for SIP,” IETF RFC3050, January 2001.[13] IEEE P802.3ae 10Gb/s Ethernet Task Force,http://grouper.ieee.org/groups/802/3/ae/<strong>in</strong>dex.html.[14] “Light<strong>in</strong>g Internet <strong>in</strong> the WAN,” TelecommunicationMagaz<strong>in</strong>e, September, 2000, http://telecomsmag.com/issues/200009/tcs/light<strong>in</strong>g_<strong>in</strong>ternet.html.Kushal Roy, born <strong>in</strong> M.P Republic <strong>of</strong> India on December13 th 1979, received his Bachelors Degree with Honors <strong>in</strong>Electronics and Communication Eng<strong>in</strong>eer<strong>in</strong>g form GovernmentEng<strong>in</strong>eer<strong>in</strong>g College Ujja<strong>in</strong>, M.P India, <strong>in</strong> the year 2002,achieved his Master’s Degree M,Phil <strong>in</strong> Instrumentation fromIndian Institute <strong>of</strong> Technology Roorkee, U.A Republic <strong>of</strong> India<strong>in</strong> the year 2004 with nano scale <strong>in</strong>strumentation and opto<strong>in</strong>strumentation as major fields <strong>of</strong> study.He is <strong>in</strong>volved extensively <strong>in</strong>volved <strong>in</strong> Research educationand development s<strong>in</strong>ce 2004 with more than 5 years <strong>of</strong>experience <strong>in</strong> teach<strong>in</strong>g undergraduate as well as post graduatestudents <strong>in</strong> various renowned Institutes across the country.Presently he is serv<strong>in</strong>g as faculty <strong>in</strong> the Department <strong>of</strong>Electronics and communication Eng<strong>in</strong>eer<strong>in</strong>g, Haldia Institute <strong>of</strong>Technology ICARE (Indian Center for Advancement <strong>in</strong>Research and Education) Complex, Haldia, West BengalRepublic <strong>of</strong> India.Mr. Roy has contributed to more than 6 <strong>in</strong>ternationalconferences papers across the globe <strong>in</strong> Italy, S<strong>in</strong>gapore,Morocco, USA etc. He is also work<strong>in</strong>g as Pr<strong>in</strong>cipal Investigatorto a sponsored project on “Study and Development <strong>of</strong> nanoscale piezo electronic material Lead Zirconium Titanate,(popularly known as PZT) by sol-gel process.” (conferred videHonorable President <strong>of</strong> India Direct sanction orderSR/FTP/ETA-49/07) worth 0.522 million INR, Science andEng<strong>in</strong>eer<strong>in</strong>g Research Council, Department <strong>of</strong> Science andTechnology, M<strong>in</strong>istry <strong>of</strong> Science and Technology Government<strong>of</strong> India.© 2010 ACADEMY PUBLISHER