Latest News
Updated:
04/21/2003
Is
802.11 Ready for VOIP?
5-Minute
Security Advisor - Strengthening Wireless Authentication
Catch-22
of WLANs
eWEEK
Excellence Awards: Networking Infrastructure
IEEE
Plots Speedier WLAN
Extreme
Springs Switch Surprise
Nortel
Launches WWAN-WLAN Products
Nortel
Preps 'Security Switch'
Wi-Fi
Developers Pursue Plans for More Services
How
to Fine-Tune Your VPN Strategy
Cisco
to Buy Linksys
Verizon's
Surprise Evolution
WLANs
Spur Security Questions
Verizon
Plans 2.4-Mbits/s Wireless Rollout
Study
Exposes WLAN Security Risks
Roaming
From WLAN to WAN
Wireless
Clouds Of Connectivity
WLAN:
The Four S's
Cisco
Bolsters Its WLAN Hand
Cisco
to License WLAN Technology
Telesuite
Virtual Conference Room
IBM
Connects Wireless Networks, Enterprise Systems
Ten
Steps to a Secure Wireless Network
Top
Vulnerabilities in Web Applications
Hospital
Cures WLAN Insecurity
System
Boosts WLAN Security
Overview of Wireless Wide Area Networks (WWANs)
Wireless WANs, which can bridge branch offices of a company, cover a much more extensive area than wireless local area networks (WLANs). Unlike WLANs, which offer limited user mobility and instead are generally used to enable the mobility of the entire network, WWANs facilitate connectivity for mobile users such as the traveling businessman. In general, WWANs allow users to maintain access to work-related applications and information while away from their office.
In wireless WANs, communication occurs predominantly through the use of radio signals over analog, digital cellular, or PCS networks, although signal transmission through microwaves and other electromagnetic waves is also possible. Today, most wireless data communication takes place across 2G cellular systems such as CDMA, PDC and GSM, or through packet-data technology over old analog systems. Although traditional analog networks, having been designed for voice rather than data transfer, have some inherent problems, some 2G (second generation) and new 3G (third generation) digital cellular networks are fully integrated for data/voice transmission. With the advent of 3G networks, transfer speeds should also increase greatly.
WWAN connectivity requires wireless modems and a wireless
network infrastructure, provided as a fee-for service by a wireless service
carrier. Portable devices receive communications as the connected wireless
modems and wireless networks interact via radio waves. The modem directly
interfaces with radio towers, which carry the signal to a mobile switching
center, where the signal is passed on to the appropriate public or private
network link (i.e., telephone, other high speed line, or the Internet).
From here, the signal can be transferred to an organization's existing
network.
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Similarly, WWANs can communicate with the Internet. For small devices such as handhelds and mobile phones, a universal specification known as wireless application protocol (WAP) exists to facilitate the delivery and presentation of Web content. The request for Web content is sent through the wireless network to a WAP gateway, where it is processed and the required information is retrieved and returned. WAP supports most wireless networks and mobile device operating systems.
As with wireless LANs, wireless WANs have many interference problems related to their reliance on terrestrial radio networks. Inclement weather conditions, rugged terrain and other naturally occurring conditions can cause prolonged latency and other disruptions to a radio channel. Nevertheless, wireless WANs have many intrinsic benefits, namely enhancing productivity through real-time information access.
Digital Cellular Systems and Personal Communications Service (PCS )
Digital cellular systems transmit information between the cellular telephone and base station in digital form, including encoded voice communications. PCS systems use the same technology as digital cellular, but occupy new higher frequency bands. Compared to analog cellular, digital cellular systems offer security through authentication and encryption, short message service (SMS - similar to paging), more flexible data services, a variety of value-added voice services (such as caller ID), longer battery life, higher capacity and ultimately lower cost of deployment per subscriber.