VOICE OVER Wi. Fi by Narendranath Kanukolanu Rahul Datta Kalyan Valluri
TOPICS o Ø Ø Ø o o 1. Introduction What is Wi. Fi What is voice over IP 2. Features 3. Architecture of Voice over Wi. Fi 4. Future prospects 5. Conclusion
WHAT IS Wi. Fi(wireless fidelity) o o o Wi. Fi is the wireless way to handle networking. It is also known as 802. 11 networking and wireless networking. The big advantage of Wi. Fi is its Simplicity. Can connect computers anywhere in home or office without the need for wires. The computers connect to the network using radio signals.
Contd… o o Wireless Fidelity is meant to be used generically when referring of any type of 802. 11 network, whether 802. 11, 802. 11 a, 802. 11 b, 802. 11 g dual-band, etc. The term is promulgated by the Wi-Fi Alliance. Wi. Fi Alliance An organization made up of leading wireless equipment and software providers.
Over view of IEEE 802. 11? o o Wireless networking hardware requires the use of underlying technology that deals with radio frequencies as well as data transmission. The most widely used standard is 802. 11 produced by the Institute of Electrical and Electronic Engineers (IEEE). This is a standard defining all aspects of Radio Frequency Wireless Networking.
Specifications in the 802. 11 family 802. 11 Applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2. 4 GHz band using either Frequency Hopping Spread Spectrum (FHSS) or Direct Sequence Spread Spectrum (DSSS). o 802. 11 a An extension to 802. 11 that applies to Wireless LANs and provides up to 54 Mbps in the 5 GHz band. 802. 11 a uses an Orthogonal Frequency Division Multiplexing encoding scheme rather than FHSS or DSSS. H o
Contd. . 802. 11 b (also referred to as 802. 11 High Rate or Wi-Fi) An extension to 802. 11 that applies to wireless LANS and provides 11 Mbps transmission (with a fallback to 5. 5, 2 and 1 Mbps) in the 2. 4 GHz band. o 802. 11 g Applies to wireless LANs and provides 20+ Mbps in the 2. 4 GHz band. o
IEEE 802. 11 WLAN Standards
An 802. 11 WLAN History o o o o o 1940: Spread spectrum technology first used by the military 1980: Limited applications using narrowband technology 1989: FCC assigns frequency for commercial use. ISM bands authorized (900 MHz, 2. 4 GHz, 5 GHz) 1990: *900 MHz products begin shipping *IEEE begins work on industry standard 1994: 2. 4 GHz products begin shipping 1997: *IEEE 802. 11 standard approved. *2. 4 GHz products begin dominating the scene 1999: *IEEE 802. 11 a&b supplements ratified. *WECA formed for interoperability testing *Wide Band Frequency Hopping NPRM Released by FCC “Enhanced MAC - Qo. S and Security” Task Group chartered 2001 Qo. S/Security draft standard formulated 2002 Has over 130 participating companies with voting members
Technology that makes Wi. Fi networking possible The Walkie Talkie Network These are small radios that can transmit and receive radio signals. When you talk into a Walkie-Talkie, your voice is picked up by a microphone, encoded onto a Radio frequency and transmitted with the antenna. Another walkie-talkie can receive the transmission with its antenna, decode your voice from the radio signal and drive a speaker.
Wi. Fi's Radio Technology o o Wi. Fi radios that work with the 802. 11 b and 802. 11 g standards transmit at 2. 4 GHz. while those that comply with the 802. 11 a standard transmit at 5 GHz. Wi. Fi radios use efficient coding techniques that also contribute to the much higher data rates. For 802. 11 a and 802. 11 g, the technique is known as Orthogonal Frequency-Division Multiplexing (OFDM). For 802. 11 b, it is called Complementary Code Keying (CCK).
Wifi SECURITY o o Wi. Fi hotspots can be open or secure. If a hotspot is open, then anyone with a Wi. Fi card can access the hotspot. If it is secure, then the user needs to know a WEP key to connect. WEP stands for Wired Equivalent Privacy.
Hardware needed to create Wi. Fi Network o o One of the best things about Wi. Fi is how simple it is. 802. 11 a, 802. 11 b or 802. 11 g network card. 802. 11 g has the advantage of higher speeds and good interoperability on 802. 11 b equipment. n n o o For a laptop, this card will normally be a PCMCIA card that you slide into a PCMCIA slot on your laptop. Or you can buy a small external adapter and plug it into a USB port. For a desktop machine, you can buy a PCI card that you install inside the machine, or a small external adapter that you connect to the computer with a USB cable. Install the card Install the drivers for the card Find an 802. 11 hotspot Access the hotspot. (A hotspot is a connection point for a Wi. Fi network)
Requirements
Vo. IP(Voice over Internet Protocol) o o A category of hardware and software that enables people to use the Internet as the transmission medium for telephone calls by sending voice data in packets using IP rather than by traditional circuit transmissions of the PSTN (Public Switched Telephone Network). In short Vo. IP transfers voice through IP packets over the Internet.
Contd. . o o Internet telephony products are sometimes called IP telephony, Voice over the Internet (VOI) or Voice over IP (Vo. IP) products. The voice traffic is converted into Data packets then routed over the Internet, or any IP network as normal data packets would be transmitted. When the data packets reach their destination, they are converted back to voice data again for the recipient.
How does Vo. IP work? o A number of years ago sending a signal to a remote destination could be done digitally. Vo. IP works by digitalizing voice in data packets, sending and reconverting them in voice.
Advantages of Digital Formats o o o Digital format can be better controlled. Compressed. Routed and converted to a new better format. Noise is tolerant than analog signals. Vo. IP uses TCP/IP (TCP/IP is an Internet protocol with a leading IP packet to control communication and the payload).
Home phone and one computer
Home Phone with more than one computer
Advantages of Vo. IP o o o It makes long-distance calls less expensive by removing some of the access charges required for use of the public telephone network. A user's physical location also becomes irrelevant. Vo. IP also enables Wi. Fi’s advanced features like checking voice mail or programming call forwarding through a web application.
Disadvantages of Vo. IP o o o Vo. IP services do not work in blackouts. Vo. IP services are only as reliable as the customer’s broadband connection. A poor quality connection can lead to voice quality issues. Luckily, high quality broadband is getting easier and easier to find these days.
Vo. Wi. Fi(Voice over Wireless Fidelity ) o o o Simply means a Wi-Fi based Vo. IP Service or in even more general terms, a wireless based Vo. IP system. Where Vo. IP consists of the hardware and software that enables people to use the Internet as the transmission medium for telephone calls. Vo. Wi. Fi is the wireless version of this technology that is designed to work on wireless devices such as a laptop or PDA.
Contd. . o Mobile voice over IP (Vo. IP) is currently limited to voice over Wi. Fi (Vo. Wi. Fi) but, with the introduction of cellular technologies providing higher bandwidth capabilities, Vo. IP is likely to move towards cellular networks.
Over view of Vo. Wi. Fi o o o Vo. Wi. Fi is a term used for technologies or services which provide voice over Wi. Fi refers to any wireless LAN products or services that are based on the IEEE 802. 11 WLAN standard with theoretical data rates ranging from 11 M to 54 Mbit/sec. A hotspot is a wireless LAN node that provides Internet connection and virtual private network (VPN) access from a given location
Contd. . o o With combined Vo. Wi. Fi/cellular phone and seamless roaming between those two networks, subscribers could use voice over a Wi. Fi network, where available, and cellular connections where Wi. Fi is missing or outside of a Wi. Fi area. Combining Vo. IP with Wi. Fi has a great potential to reduce the cost of voice services, in particular for roaming and for access to broadband services, while increasing the convenience to users.
Deployment of Vo. Wi. Fi o The requirements of the three main segments making up the WLAN marketplace also will have an effect on the deployment parameters of WLANs. These three market segments are
Contd. . o o Residential/SOHO (small office, home office) cordless phones or scaled down PBXs that will function as part of an integrated gateway Enterprise mobile Vo. IP WLAN network (private network) Cellular off-load network (Vo. IP over WLAN in hot spots, which in turn interfaces to the public telephone network) Such a network would allow seamless multiple access options for most of the more prevalent voice and data services.
Architecture Requirements o o In the context of Vo Wi. Fi and Vo. Wi. Fi-Mobile roaming many of the current deployments of Vo. Wi. Fi involve integration with enterprise PBXs One method of integrating with a traditional PBX is to use a Vo Wi. Fi gateway. The calls are routed from the Vo Wi. Fi phone to Vo Wi. Fi gateway via the Wi. Fi Access Point and the Vo Wi. Fi gateway transmits calls to the existing PBX. Integration with PBX allows calls to be placed to and received from the PSTN, and also supports PBX features such as call forwarding messaging and conference calling.
Contd. . o Another way to use Vo Wi. Fi is to use softphones on mobile computers or PDAs which route calls entirely over the internet in Wi. Fi areas such as HOT SPOTS.
Architecture Of Vo. Wi. Fi
Contd. . o o o The gateway connects to the mobile switching centre for cellular calls, and connects to the data network for Wi. Fi calls. The gateway manages subscriber access and handoff. As the subscriber moves within range of a wireless access point, the gateway authorizes the subscriber’s access and all network services — both voice and data — are delivered over the Wi. Fi. When the subscriber moves outside of the Wi. Fi coverage area, the gateway seamlessly switches control over to another Wi. Fi network or the mobile networkdeploying a Vo. Wi. Fi/mobile roaming solution requires dual-mode handsets that support both Vo. Wi. Fi as well as mobile
Drivers of Vo. Wi. Fi Development and Vo. Wi. Fi/mobile Convergence o o o Wi. Fi and Vo. IP are being widely deployed in enterprises. Wi. Fi is easy and flexible to deploy, and is claimed to be more reliable in terms of coverage while costing less than traditional cellular services. It is also expected that using Vo. Wi. Fi new converged applications can be developed for mobile workers with new capabilities such as geographic location information and instant messaging.
Contd. . o o In this early stage of the Vo. Wi. Fi market, the handsets and Vo. Wi. Fi services have been focused on enterprise or corporate users and are expected to do so in the next few years The main reason is because Vo. Wi. Fi is related to the increasing deployment of Wi. Fi and Vo. IP in corporate environments
Why would mobile service providers want to provide Vo. Wi. Fi? o o At first glance, it would seem that mobile operators would be disadvantaged by providing roaming services with Wi. Fi because they may lose revenue generated by traditional mobile roaming services. Generally, Wi. Fi services are provided at a lower price than mobile services or even free, which has induced mobile service providers, especially 3 G service providers, to consider Wi. Fi and Vo. Wi. Fi services to be competitive with their mobile services.
Contd. . o recent proliferation of Wi. Fi in enterprises and in the number of hotspots in densely populated areas in a relatively short period of time, several mobile service providers have started to regard Vo. Wi. Fi and Vo. Wi. Fi/mobile roaming as a way of reducing prices for their customers and consider Wi. Fi as a means to enhance competition and differentiate their service from that of competitors.
Impact of Wi. Fi and Vo. Wi. Fi on 3 G Development o o o Vo. Wi. Fi, or Vo. IP over Wi. Fi, allows users to make voice calls and access video and data at a low price. The development of this service will have an impact on 3 G services and the way they are structured and priced While 3 G has the advantage of ubiquitous access, the data transfer speed is about a half megabit per second slower than Wi. Fi’s top speed.
User benefits from Vo. Wi. Fi interconnecting with mobile networks o o o Users of dual handsets will be able to make calls more cheaply than those using mobile phones. Calls generated in hotspots or WLANs are likely to result in considerable savings by consumers. Vo. Wi. Fi also provides innovative new features such as the ability to access e-mail, Internet, location information, etc. at a lower price
Contd. . o Another benefit for existing users of Vo. Wi. Fi service is that they are no longer constrained in obtaining service from a limited area such as a hotspot or within a company, but are able to have real mobility and ubiquitous access to voice calls as well as data and video by seamless interconnection with mobile networks with a single handset or portable computer
IEEE 802. 11 Protocol Architecture
Technical issues and standard development of Vo. Wi. Fi o Ø § § Since Vo. Wi. Fi is technically based on Vo. IP over Wi. Fi, quite a few technical issues and challenges are similar to those in Wi. Fi and Vo. IP Quality of Service (Qo. S) Wi. Fi has its own Qo. S challenges in that throughput may fluctuate when roaming among Access Points. Subscribers are more sensitive to perceptible service degradation for voice or video than for data. Therefore, more reliable Qo. S is necessary for voice to be delivered satisfactorily over Wi. Fi
Contd. . § § § The issue of Qo. S will be increasingly important when roaming between Wi. Fi and mobile networks is supported, given that network hand-off can result in quality of service degradation. Up to now, most wireless equipments did not yet incorporate Qo. S because they were to emerge. Without standards, local voice systems over Wi. Fi have been provided as bundles of proprietary wireless network hardware and software. The Wi. Fi Alliance announced a new Wi. Fi Multimedia (WMM) program to deal with quality of service issues in September 2004. 41 The WMM program combines core elements of the 802. 11 e draft and a simplified packet priority access category scheme borrowed from IEEE 802. 11 d. WMM is designed to improve the Qo. S for voice, audio, video and multi-media applications over Wi. Fi.
Contd. . o o Quality of Service is hard to find these days, but Qo. S standards for high quality Vo. Wi. Fi are a work in progress. 802. 11 e includes what the Wi-Fi Alliance phrases as Wi-Fi Multimedia Extensions (WMM, or WME) for prioritization.
Contd. . o Ø Ø WMM includes four access categories: Voice Priority, the highest level, is intended to support multiple simultaneous, toll-quality voice calls with low latency. Video Priority, the next highest level, prioritizes video relative to all other data traffic. One 802. 11 a/g channel can support three-four SDTV (Standard Definition TV) data streams, or one HDTV (High Definition TV) stream.
Contd. . Ø Ø Best Effort Priority is intended to support traffic from legacy devices, or from applications or devices that lack Qo. S capabilities. Best effort traffic is less sensitive to latency than voice or video. Internet surfing is an example. Background Priority is intended to support low priority traffic that does not have strict latency and throughput requirements. File downloads and print jobs are cited as examples.
Contd. . Ø Ø There exist a number of proprietary Qo. S mechanisms such as Spectra. Link Voice Priority (SVP), used on Spectra. Link phones. Qo. S requires not only prioritization, but also smooth handoffs as the handset moves from cell to cell.
Ø § § § Proper bandwidth With the wide deployment of Wi. Fi in hotspots and in enterprises, the need for higher-speed Wi. Fi is also increasing. Applications over Wi. Fi use an increasing amount of bandwidth The number of users and devices connecting to Wi. Fi are increasing and the bandwidth demand is expected to increase with the provision of Wi. Fi/mobile roaming
Ø § § § Security and privacy The potential security and privacy risks arising from using Wi. Fi for voice have been an obstacle to further development of Vo. Wi. Fi/mobile roaming Those risks include stealing packets, unauthorised access to the network and intentional interference by outsiders whichhas a greater impact on business users than residential subscribers. In general, encryption presently used such as Wired Equivalent Privacy (WEP) is considered weak and susceptible to outside intrusion
Ø § § Interoperability The adoption of heterogeneous Wi. Fi technologies may cause incompatibilities With the advance of Wi. Fi and Vo. Wi. Fi, a growing number of vendors are trying to differentiate their products beyond existing standards, mainly by boosting speed or security.
Ø § Interference and complexity The spectrum for Wi. Fi is not dedicated and licensed for use by certain entities as in the case of mobile services. Therefore, the users of Wi. Fi share spectrum with other devices, including household devices such as microwaves. § Consequently, as Wi. Fi or Vo. Wi. Fi deploys further, the spectrum will become increasingly crowded and the possibility of interferences will grow
Various facts of network capacity planning for the future deployment of Vo. WLAN o o Over-subscription of voice networks (voice concentration) Throughput requirements for typical voice, video and media applications using IP packet technology WLAN network capacity for enterprise applications RF frequency planning and reuse for large network deployments WLAN network capacity for home applications Consideration of wireless repeaters (mesh) to extend home coverage
Over-subscription of Voice Services (Concentration) o o A basic understanding of oversubscription, for example, can assist network planners who are evaluating network capacity for enterprise Vo. IP over WLAN applications. PSTN Phone lines typically are terminated at a Class 5 switch or a Digital Loop Carrier (DLC) connected to a Class 5 switch. The Class 5 switch manages call connections and rejects calls when the system capacity has been reached
Contd. . o In cellular networks, some consideration is given to reserve a fraction of the active phone line capacity for handoff purposes between one cell and the next.
Voice Throughput over IP o o o Voice Compression and Vo. IP Voice compression algorithms help US TO derive as much capacity from an infrastructure as possible, but compression algorithms involve tradeoffs between efficiency and overhead that planners should consider. In wireless networks, voice is digitized with the G. 711 coding standard and transported at 64 Kbps.
Contd. . o o While G. 711 is the mainstream digital codec for tollquality voice services, a number of more efficient codes are used for both cellular and voice "pair gain applications. " In an IP network, voice codecs are placed into packets with durations of 5, 10 or 20 msec of sampled voice, and these samples are encapsulated in a Vo. IP packet.
Throughput of WLAN Access Points o To optimize the network capacity of a WLAN with a voice special attention to the throughput of the APs which govern how quickly data of any sort can be placed on the network has to be given.
Contd. . The following two basic functions affect the throughput of an AP: Ø 1. Area and modulation density supported by the cell a. Small cells can support high data rate modulations (peak rates) b. Larger cells will use lower rate 802. 11 modulations and are an aggregate sum of areas covered and the modulation rate o
Contd. . o Ø Ø 2. The WLAN MAC protocols have the following effects: a. The Ethernet (CSMA/CA) protocols, DCF and EDCF, limit capacity at approximately 37% of the peak data rate b. Scheduled TDMA protocols such as HCF can theoretically reach around 90% capacity of the network, but under full load they will typically carry only approximately 75% of capacity c. DCF/EDCF MAC protocols do not effectively manage network latencies as the capacity limit is approached d. HCF protocols control latencies by providing fair weighted queuing so that all users will receive service even under full load conditions
Application of Small-mesh Access Points for Residential Coverage o o Access points for the residential/SOHO marketplace, cell coverage and throughput are the most crucial issues facing WLAN implementations in this market. Wireless repeaters, which can be used to implement small mesh residential networks, are a low-cost method of improving coverage and throughput.
Contd. . o One possible technique for extending coverage and improving residential service is the use of multiple APs in a mesh/repeater architecture.
Residential Network Topology
A simple example featuring two access points
Contd. . o Ø Ø There are two possibilities for operating a residential mesh network. They are the following: Single-Frequency Mode: Access points are not dual-mode and can only support a single frequency of operation from an AP to another AP and from an AP to a client/subscriber. Dual-Frequency Mode: Access points are dual frequency, supporting two separate links on two separate frequencies simultaneously.
Dual Frequency Mode
Access Time Delay o o Ø Ø The time delay and jitter of the Vo. IP system will be a design consideration. The two following issues relate to time delay and jitter: 1. Signaling for call set up, tear down and other call control communications will be delayed. (Worst case delay is the principal concern. ) 2. Jitter in the voice traffic/bearer channel will cause delay.
Delays in the communication path for an enterprise network
Delays in the communication path for an Residential network
Deploying Vo. IP over WLANs o The technology needed to deploy Vo. IP over WLANs and the other wireless applications is being incorporated into next generation handsets, mobile devices, personal digital assistants (PDAs), laptop computers, infrastructure systems and other types of systems.
Dartmouth Deployment o o o o Full VOIP Software by end of 2003 Campus wide WLAN Network 1000 Freshman Outbound, Inbound Calls Free Wired, Wireless & LD PCs, PDAs, other devices Traffic & Usage Study 13, 000 Students, Faculty & Staff
Advantages of Vo. Wi. Fi o o Mobility is the primary selling point, much as it is with cell phones. Vo. Wi. Fi has the advantage of no airtime charges. As a wireless technology, there are no wires to run to Wi-Fi phones. Therefore, network configuration and reconfiguration processes are fast.
Disadvantages of Vo. Wi. Fi o o o Vo. IP and Wi-Fi are both immature technologies, so merging the two into Vo. Wi. Fi carries some associated risks. Standards are still in development, and some early pre-standard versions may not be upgradeable to compliance level. As a data-centric LAN technology, Wi-Fi involves a shared medium in the form of frequency bands creating issues of contention and congestion.
Contd. . o o o Troublesome for stream-oriented communications such as voice, and especially so when handoffs are required as the user roams between APs. Costs have to be considered, of course, and the cost of a Vo. Wi. Fi LAN can be double that of a data-only WLAN. Wi-Fi phones are easily double the cost of a typical cordless phone.
Contd. . o Current Wi-Fi phones don’t have much, although the next generation or two should overcome that issue.
Benefits o o Vo. Wi. Fi delivers a simpler, less expensive and more flexible system for providing mobile data and voice communications than other technologies that require the implementation and maintenance of separate systems for each. Vo. Wi. Fi also offers greater reliability and voice quality than alternatives such as cellular technology.
Technical Challenges o o o Deliver High Quality without Qo. S Deal with High Packet Loss on WLANs Roaming Across WLAN Network Segments Roaming From WLAN to Cellular Compatibility with Firewalls
FUTURE o o o The number of businesses using voice over wireless local area networks (Vo. WLAN) is set to triple over the next two years A new report from Infonetics Research has found that 10 per cent of north American businesses are now using Vo. WLAN. The researchers expect that percentage to reach 31 per cent by 2007. The main reasons now holding back the uptake of wireless LANs in business are fears over security and privacy.
More Places to Use nt 1 02. 8 1 F i tpr oo Wi-Fi PDAs & Laptops Wireless VOIP Growth Mo More Wi-Fi Devices bil e Us ers More Mobile Users
Conclusion o o o Technology exists today to implement Vo. IP over WLANs applications as an integral part of nextgeneration seamless wireless voice/data networks. The wireless industry has already begun to migrate toward an environment where one phone number can be used practically anywhere for voice and data applications. To accomplish this goal, mobile device designers, carriers, service providers and enterprise/home network designers face deployment, provisioning and implementation issues.
References o o o http: //www. wifiplanet. com/news/article. php/1015241 http: //www. cisco. com/en/US/products/hw/phon es/ps 379/products_administration_guide_chapter 09186 a 008024662 c. html http: //www. technologyreview. com/articles/04/0 8/wo_brown 081104. asp http: //www. wired. com/wired/archive/11. 06/star t. html? pg=8 http: //www. wi-fitechnology. com/wifi_forum_submit_news. shtml http: //www. crm 2 day. com/experts/EEp. AZyu. Au. Vg Lprs. EUp. php
o o o o Source: http: //news. zdnet. com/2100 -1035_225571870. html http: //www. wi-fitechnology. com/user. php http: //www. telecomasia. net/telecomasia/article/ article. Detail. jsp? id=168107 http: //www. commweb. com/show. Article. jhtml? art icle. Id=168601894 http: //www. google. com/search? hl=en&q=find+v oice+over+wifi www. intel. com www. doceotech. com
QUESTIONS o o o 1. What are the technical issues and challenges involved in Vo. Wi. Fi? Write about the quality of service in Vo. Wi. Fi? 2. Advantages and Disadvantages of Vo. Wi. Fi? 3. What are the Common Vo Wi. Fi Infrastructure Problems?
SOLUTIONS o o 1. The Technical issues of Vo. Wi. Fi are Quality of Service (Qo. S) Proper bandwidth Security and privacy Interoperability Interference and complexity The Technical challenges are Deliver High Quality without Qo. S Deal with High Packet Loss on WLANs Roaming Across WLAN Network Segments Roaming From WLAN to Cellular Compatibility with Firewalls
o o o 2. The Advantages of Vo. Wi. Fi Mobility is the primary selling point, much as it is with cell phones. Vo. Wi. Fi has the advantage of no airtime charges. As a wireless technology, there are no wires to run to Wi-Fi phones. Therefore, network configuration and reconfiguration processes are fast. Vo. Wi. Fi delivers a simpler, less expensive and more flexible system for providing mobile data and voice communications than other technologies that require the implementation and maintenance of separate systems for each. Vo. Wi. Fi also offers greater reliability and voice quality than alternatives such as cellular technology
o o o o Disadvantages of Vo. Wi. Fi. Vo. IP and Wi-Fi are both immature technologies, so merging the two into Vo. Wi. Fi carries some associated risks. Standards are still in development, and some early pre-standard versions may not be upgradeable to compliance level. As a data-centric LAN technology, Wi-Fi involves a shared medium in the form of frequency bands creating issues of contention and congestion Troublesome for stream-oriented communications such as voice, and especially so when handoffs are required as the user roams between APs. Costs have to be considered, of course, and the cost of a Vo. Wi. Fi LAN can be double that of a data-only WLAN. Wi-Fi phones are easily double the cost of a typical cordless phone. Current Wi-Fi phones don’t have much, although the next generation or two should overcome that issue.
3. Scalability Quality of Service Usability
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