Chapter 10: Conclusion

Eventually, the Internet will replace the Public Switched Telephone Network (PSTN), but many technological changes will have to take place in order for this forecast to come to fruition. One major element will be the establishment of a faster connection to the Internet from the residence and small enterprise. In the foreseeable future, broadband Internet access will be limited if it is to be delivered by the duopoly of cable modems and Digital Subscriber Lines (DSLs).

802.11 and associated wireless technologies pose the greatest promise for a relatively rapid rollout of ubiquitous broadband Internet access. Clayton Christensen's definition of disruptive technology is that which is "cheaper, simpler, smaller, and more convenient to use." When compared, infrastructure-wise, to DSL (from the telephone company) and cable modems, 802.11 undoubtedly meets Christensen's definition.

Objections to 802.11

Four major objections have been made to the proposal to adopt 802.11 as a Last Mile solution, that is, access to a greater network, be it the Internet or the PSTN. Those objections are range, security, quality of service (QoS), and concern over interference from other Part 15 users in the unlicensed spectrum. In order to replace the PSTN's copper wire or cable TV's coax cable as Last Mile access, 802.11 as a technology must meet or exceed the performance of those forms of access. In addition, 802.11 has qualities of its own where its adoption will outweigh any disadvantages it has vis-à-vis copper wire or cable's coax.

Range as Limitation

One of the first tasks of this book has been to overcome the misperception that 802.11 is limited in range to approximately 100 meters. The range of 802.11 is a function of power and antenna technology. In order for 802.11 to achieve wide acceptance in residential and small office / home office (SOHO) markets, it will have to offer a range that makes it economical for the service provider to cover American suburbs. Achievements in power levels and directional antenna design have enabled 802.11 to facilitate point-to-point access in excess of 20 miles. Phased array antenna technology offers the potential of a "wireless switch" where different subscribers in a locale covered by one phased array antenna can receive differing levels of bandwidth and service.

The next question focuses on how bandwidth is delivered to a residential subscriber if the only source of bandwidth is the telephone company's T1 service. Developments in tiered network technologies and 802.16 offer the promise that bandwidth in excess of 100 Mbps can be distributed to subcarriers who can then deliver service to their subscribers and microcarriers at speeds of 11 Mbps (802.11b), 20 Mbps (802.11g), or 54 Mbps (802.11a). Wireless metro area networks (WMANs) have the potential to service large enterprise customers and subcarriers alike. The construction of infrastructure for this model of bandwidth distribution is far less expensive than fiber optic or other broadband schemes.

Security Fixes for 802.11

Another major objection to 802.11 is the misperception that it is inherently insecure. 802.11 contains a number of security mechanisms; the most prominent is Wired Equivalent Privacy (WEP). Any network security plan must use an equation that balances the value of information on the network (military intelligence, bank records, or email jokes) with the threat to the network (foreign intelligence agencies and inquisitive neighbors) with the cost of security measures in dollar terms (virtual private networks [VPNs], firewalls, and so on). 128-bit WEP contained in 802.11 is probably adequate for most residential and small enterprise applications. Users that need greater security can add VPNs, firewalls, and other additional measures to strengthen security on their network.

QoS or fear of interference from other Part 15 wireless users is perhaps the chief objection to 802.11. Major strides have been made in 802.11 QoS with the introduction of 802.11e, which is specifically aimed at improving QoS in 802.11 networks. 802.11e is based on over a decade of experience in the design of wireless local area network (WLAN) protocols and was built from the ground up for real-world wireless conditions. 802.11e is backwards compatible with 802.11; that is, non-802.11e terminals can receive QoS-enabled application streams.

QoS on 802.11 Networks

802.11 networks are potentially capable of delivering QoS comparable to the PSTN. It should be noted that the Regional Bell Operating Companies (RBOCs) have been losing phone lines to cell phone service providers at an alarming rate (for the RBOCs) over the last year. In fact, the RBOCs have recorded, percentage-wise, their first decline in lines in use since the Great Depression. Cell phone service is admittedly inferior in quality to that of the PSTN. The motivating factor, however, for landline customers to drop their service from the RBOC is the convenience offered by the cell phone as well as certain price advantages (free long distance in offpeak hours). The point here is that, ultimately, the QoS of the PSTN is not an absolute requirement for consumers. Consumers, in the case of cell phones, have traded off QoS for convenience and price. The PSTN is doomed if it must compete with 802.11 in that 802.11 using 802.11e potentially delivers a comparable QoS in both voice and data services while offering data rates up to 11 Mbps (compare with most DSL plans at 256 Kbps).

Voice over 802.11 (Vo802.11)

Segueing from QoS is the concept of routing voice traffic over 802.11 networks. The focus on QoS makes routing voice over 802.11 possible. Here is another performance parameter where 802.11 must match the capabilities of the PSTN in order for the technology to achieve wide acceptance. The Vo802.11 industry is very much in its infancy and is largely limited to in-building enterprise applications interfacing with conventional private branch exchanges (PBXs). However, some case studies point to the use of 802.11 to transmit voice point to point in a range of 19 miles. This is service that competes directly with the telephone company's Last Mile monopoly. The advent of softswitch technologies and Internet Protocol (IP) backbones makes it entirely possible to route phone calls that never touch the PSTN.

Economics of 802.11

Money makes the world go around. 802.11 offers a number of economic advantages over wired networks. In enterprise networks where 802.11 is only marginally cheaper to deploy than wired networks, 802.11 excels over wired network technology in that it offers the potential to make employees more efficient. It also reduces the costs of moves, adds, and changes. The chief market for 802.11 services at the time of this writing is in hotspots. Hotspots cover limited areas such as airports, coffee shops, and hotels. From these hotspots, 802.11 will gradually spread to a point where whole metropolitan areas are covered.

One significant economic advantage of 802.11 over the copper wire of the telephone company is the cost of deploying service. If a firm wants to compete with the phone company for service, it has two options. The first is to lease facilities from the phone company (called unbundled network elements [UNEs]), which are fairly economical if the competitor can get by the legal barriers the incumbents have been known to establish. The second is to deploy their own copper wire to the household, which can cost from $1,000 per household for an urban location to $10,000 for rural deployment. Considering the subscriber may only order basic phone service at $30 a month, the return on investment (ROI) on wired service is too long to be considered feasible; hence, only 8 percent of Americans have their choice of local telephone service providers.

The chief expense to deploy 802.11 service in a residential market is the customer premise equipment (CPE), which may run as much as $300 per residence and is falling quickly as new vendors enter the market. The expense of offering wireless service to a household is potentially considerably less than deploying new copper wire service. It is this difference in cost that will accelerate the deployment of wireless broadband service. The debate rages as to whether this rollout will occur from the top down from existing service providers or from the bottom up from new market entrants. Perhaps the competition between the two camps will expedite the rollout of this service much to the benefit of the consumer. Economists Charles Jackson and Robert Crandall estimate that ubiquitous broadband would reap a $500 billion annual benefit to the U.S. economy.

Regulatory Environment for 802.11

Finally, another objecting view toward 802.11 is the fact that it uses unlicensed spectrum, which means any other competing service or appliance can introduce interference in the network, resulting in poor service to the end user. This is known as the tragedy of the commons. The alternative to unlicensed spectrum is licensed spectrum. Spectrum licenses for a particular frequency or band of frequencies are sold at auction. Licenses for spectrum dedicated to third-generation (3G) services offered by cell phone companies have committed those firms to billions of dollars of license costs. Given the cost of spectrum, few service providers can enter that market space. Other objections run the possibility that incumbents will lobby the government to make "free" spectrum no longer "free" any more.

The solution for the tragedy of the commons is twofold. First, it is entirely possible to engineer around interference regardless of the source. Secondly, the U.S. government is about to alter its spectrum management policy, which is based on the Radio Act of 1927. The Federal Communications Commission (FCC) has issued a series of reports that study issues such as spectrum scarcity, interference, government command and control of the spectrum, and the public's interest. It is possible that the FCC will offer sweeping reform of spectrum management that will favor wireless Internet service providers (WISPs).

Congress may also get into the act. At the time of this writing, new legislation is being introduced into Congress that would open 255 MHz of spectrum for unlicensed usage. With this much more spectrum to use, less likelihood of interference exists.



Wi-Fi Handbook(c) Building 802.11b Wireless Networks
Wi-Fi Handbook : Building 802.11b Wireless Networks
ISBN: 0071412514
EAN: 2147483647
Year: 2003
Pages: 96

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