The Wireless Internet is not just wireless communications across
town or the country. It is also local—sometimes in a home or
office building. Wireless LANs are just becoming popular with
economically priced wireless Ethernet equipment. Standards
such as IEEE 802.11, HiperLAN2, and Home RF are leading the
way to untethered communications in-building or outside over
small areas. Another important development is the Personal Area
Network, also known as Bluetooth. Let’s take a look at each of
these to see how they further promote Wireless Internet sessions. 90
IT Certification CCIE,CCNP,CCIP,CCNA,CCSP,Cisco Network Optimization and Security Tips
OMNISKY
OmniSky’s Wireless Internet service uses the CDPD packetbased
network, encompassing over 172 million people. The
first service began in May 2000. Data rates are 19.2 Kbps and
users are offered a flat-rate monthly fee for unlimited service.
Much of Omnisky’s success can be attributed to the partners
it has chosen to work with: Palm, Handspring, HP, and
Compaq. However, Omnisky should be feeling the competition
when cellular begins next-generation service.
network, encompassing over 172 million people. The
first service began in May 2000. Data rates are 19.2 Kbps and
users are offered a flat-rate monthly fee for unlimited service.
Much of Omnisky’s success can be attributed to the partners
it has chosen to work with: Palm, Handspring, HP, and
Compaq. However, Omnisky should be feeling the competition
when cellular begins next-generation service.
MOBITEX OR RAM MOBILE DATA
Mobitex enjoys wide acceptance as a global standard for wireless
data networks. This technology was originally developed by
Swedish Telecom as a private network similar in purpose to the
Ardis network. The network became commercial in 1986. Since
then, many networks have been deployed in Europe, the United
States, and Australia. The frequency varies by country but the
United States and Canada mainly use 900 MHz. In the United
States, Mobitex is operated by RAM Mobile Data, a subsidiary of
Bell South. There are over 1,200 base stations installed nationwide
with service in more than 7,700 cities and towns, covering
approximately 93 percent of America’s urban business population.
Mobitex technology offers six distinguishing features that
other networks lack:
• Transparent, seamless roaming
• Store-and-forward
• Dependability (99.99 percent)
• Interoperability and connectivity options
• Capacity to support millions of subscribers
• Security second to none
Channels use 12.5 kHz bandwidth and support a data rate
of 8 Kbps. The network operates in the United States at 935
MHz to 940 MHz for the downlink (base to mobile) and 896
MHz to 901 MHz for the uplink (mobile to base).
data networks. This technology was originally developed by
Swedish Telecom as a private network similar in purpose to the
Ardis network. The network became commercial in 1986. Since
then, many networks have been deployed in Europe, the United
States, and Australia. The frequency varies by country but the
United States and Canada mainly use 900 MHz. In the United
States, Mobitex is operated by RAM Mobile Data, a subsidiary of
Bell South. There are over 1,200 base stations installed nationwide
with service in more than 7,700 cities and towns, covering
approximately 93 percent of America’s urban business population.
Mobitex technology offers six distinguishing features that
other networks lack:
• Transparent, seamless roaming
• Store-and-forward
• Dependability (99.99 percent)
• Interoperability and connectivity options
• Capacity to support millions of subscribers
• Security second to none
Channels use 12.5 kHz bandwidth and support a data rate
of 8 Kbps. The network operates in the United States at 935
MHz to 940 MHz for the downlink (base to mobile) and 896
MHz to 901 MHz for the uplink (mobile to base).
RICOCHET
Ricochet is the only wireless packet data network today that
was built from the ground up to handle high speed data, up to
128 Kbps. Modems are available from third-party sources that
allow connection to laptop computers by at least one Pocket
PC. The network has about 41,000 customers in 15 markets as
of July 2001 but the parent company, Metricom, has filed for
Chapter 11 in bankruptcy court, so anything could happen to
Ricochet. On August 8, 2001, Metricom ceased operations of
Ricochet but the company is negotiating with third parties to
buy the Ricochet network. If a third party can buy the network
at a really good price, then Ricochet may continue in some
form. As of the publishing of this book, the outcome is
unknown. The high costs of building out a nationwide network
far exceeded the revenue, and current economic conditions
make financing very difficult.
The Ricochet radio network utilizes several elements
including microcell radios and wired access points. This provides
true Wireless Internet access to information—regardless
of where it resides either on the Web or the intranet, in an
email message or a video clip.
In many ways the Ricochet network functions similarly to a
wireless Ethernet network. Acquisition is a necessary first step
for each radio on the network. The user radio, when first turned
on, must locate neighboring radios and Ricochet modems by
sending out synchronization packets. On acknowledgment from
neighboring radios, it must then get the authorization from the
name server. Only then does it join the network.
The network operates in two Industrial, Scientific, Medical
(ISM) bands of regulated, unlicensed spectrum, the 900 MHz
band and the 2.4 GHz band, in addition to the licensed 2.3
GHz Wireless Communications Systems (WCS) spectrum. The
physical layer uses Frequency Hopping Spread Spectrum
(FHSS) technology.
was built from the ground up to handle high speed data, up to
128 Kbps. Modems are available from third-party sources that
allow connection to laptop computers by at least one Pocket
PC. The network has about 41,000 customers in 15 markets as
of July 2001 but the parent company, Metricom, has filed for
Chapter 11 in bankruptcy court, so anything could happen to
Ricochet. On August 8, 2001, Metricom ceased operations of
Ricochet but the company is negotiating with third parties to
buy the Ricochet network. If a third party can buy the network
at a really good price, then Ricochet may continue in some
form. As of the publishing of this book, the outcome is
unknown. The high costs of building out a nationwide network
far exceeded the revenue, and current economic conditions
make financing very difficult.
The Ricochet radio network utilizes several elements
including microcell radios and wired access points. This provides
true Wireless Internet access to information—regardless
of where it resides either on the Web or the intranet, in an
email message or a video clip.
In many ways the Ricochet network functions similarly to a
wireless Ethernet network. Acquisition is a necessary first step
for each radio on the network. The user radio, when first turned
on, must locate neighboring radios and Ricochet modems by
sending out synchronization packets. On acknowledgment from
neighboring radios, it must then get the authorization from the
name server. Only then does it join the network.
The network operates in two Industrial, Scientific, Medical
(ISM) bands of regulated, unlicensed spectrum, the 900 MHz
band and the 2.4 GHz band, in addition to the licensed 2.3
GHz Wireless Communications Systems (WCS) spectrum. The
physical layer uses Frequency Hopping Spread Spectrum
(FHSS) technology.
ARDIS (DATATAC)
Advanced Radio Data Information Services (Ardis) sometimes
referred to as the DataTAC network, is a two-way radio service
that is based on Motorola’s RD-LAP technology. It was originally
created and jointly owned by Motorola and IBM to serve
IBM field technicians. Coverage includes about 90 percent of
the urban business population in the U.S with more than 400
metropolitan areas in the United States, Puerto Rico, and the
Virgin Islands.
The network is based on packet-data transfer using data
rates as high as 19.2 Kbps. Some areas may not offer rates as
high as 19.2 Kbps if they are not enhanced with RD-LAP.
Frequencies and protocols are proprietary to Motorola.
Modulation at the physical layer is Gaussian Frequency Shift
Keying (GFSK).
referred to as the DataTAC network, is a two-way radio service
that is based on Motorola’s RD-LAP technology. It was originally
created and jointly owned by Motorola and IBM to serve
IBM field technicians. Coverage includes about 90 percent of
the urban business population in the U.S with more than 400
metropolitan areas in the United States, Puerto Rico, and the
Virgin Islands.
The network is based on packet-data transfer using data
rates as high as 19.2 Kbps. Some areas may not offer rates as
high as 19.2 Kbps if they are not enhanced with RD-LAP.
Frequencies and protocols are proprietary to Motorola.
Modulation at the physical layer is Gaussian Frequency Shift
Keying (GFSK).
COMPAQ
Compaq Pocket PC products have the greatest number of
options for Wireless Internet of all PDAs and Pocket PCs.
Through third-party suppliers, a user may select PCMCIA
modems using CDPD, Ricochet, or CDMA networks.
options for Wireless Internet of all PDAs and Pocket PCs.
Through third-party suppliers, a user may select PCMCIA
modems using CDPD, Ricochet, or CDMA networks.
HP
Wireless Internet solutions for HP products, PDAs, and Pocket
PCs are CDPD modems sold by third parties.
PCs are CDPD modems sold by third parties.
HANDSPRING
Handspring products also use CDPD modems, just like Palm,
for wireless communications. In addition to CDPD modems,
Handspring offers an IEEE 802.11b wireless LAN option,
which offers connection speeds up to 11 Mbps in a WLAN
environment. A third wireless option for Handspring products
is a wireless modem connecting to the Glenayre messaging network
through SkyTel service. This is basically email service
through two-way paging and not suitable for Wireless Internet.
for wireless communications. In addition to CDPD modems,
Handspring offers an IEEE 802.11b wireless LAN option,
which offers connection speeds up to 11 Mbps in a WLAN
environment. A third wireless option for Handspring products
is a wireless modem connecting to the Glenayre messaging network
through SkyTel service. This is basically email service
through two-way paging and not suitable for Wireless Internet.
PALM
Palm offers several Wireless Internet options. Their integrated
wireless solution is the Palm VIIx with service provided by
Mobitex. Other Palm products can add a modem or connect to
a cellular phone. One wireless service used by Palm is OmniSky,
which offers CDPD at 19.2 Kbps. This, of course, operates over
an analog cellular network. Because analog cellular coverage is
very ubiquitous in North America, this provides broad user coverage
when traveling. It also carries all of the advantages of
CDPD, like packet data transmission and always-on mode.
Downloading Web pages with Palm products involves a little
trick called Web clipping. The user requests a particular
piece of information in a query, and the page is returned minus
a lot of the extraneous details. A server gateway is used to optimize
the content for displaying on the handheld PDA.
wireless solution is the Palm VIIx with service provided by
Mobitex. Other Palm products can add a modem or connect to
a cellular phone. One wireless service used by Palm is OmniSky,
which offers CDPD at 19.2 Kbps. This, of course, operates over
an analog cellular network. Because analog cellular coverage is
very ubiquitous in North America, this provides broad user coverage
when traveling. It also carries all of the advantages of
CDPD, like packet data transmission and always-on mode.
Downloading Web pages with Palm products involves a little
trick called Web clipping. The user requests a particular
piece of information in a query, and the page is returned minus
a lot of the extraneous details. A server gateway is used to optimize
the content for displaying on the handheld PDA.
RIM AND BLACKBERRY
Research in Motion makes RIM and Blackberry wireless handheld
models for a variety of applications and personal preferences,
including an OEM version. Some models are primarily for
Internet email, whereas other models include the functionality
to run application software such as calendars, address books,
and much more. The devices fit in the palm of a user’s hand and
are lightweight. Wireless communications is through one of two
different networks, Mobitex or DataTAC (Ardis Network).
Both Mobitex and DataTAC are packet-switched, narrowband
PCS networks designed for wide-area wireless data communication
at a data rate of 19.2 Kbps. They provide always-on connections
with extensive coverage and in-building penetration,
seamless roaming, fast messaging, high reliability, and advanced
messaging services. Dialing up to retrieve emails is unnecessary.
models for a variety of applications and personal preferences,
including an OEM version. Some models are primarily for
Internet email, whereas other models include the functionality
to run application software such as calendars, address books,
and much more. The devices fit in the palm of a user’s hand and
are lightweight. Wireless communications is through one of two
different networks, Mobitex or DataTAC (Ardis Network).
Both Mobitex and DataTAC are packet-switched, narrowband
PCS networks designed for wide-area wireless data communication
at a data rate of 19.2 Kbps. They provide always-on connections
with extensive coverage and in-building penetration,
seamless roaming, fast messaging, high reliability, and advanced
messaging services. Dialing up to retrieve emails is unnecessary.
PDA AND POCKET PC TECHNOLOGIES
Wireless devices are not always cellular phones. In fact, they do
not even need voice capabilities. Does you home PC have a
telephone receiver hanging on it? Of course not: The computer’s
primary function is to do meaningful data crunching!
Personal digital assistants and pocket PCs were created to
provide a certain level of support for the mobile user, which
could only previously be available on a laptop PC, but smaller
and lighter. They are not primarily voice communications
devices—they are for storage, retrieval, and manipulation of
data. Some PDAs and pocket PCs may attach to a cellular
phone or other type of wireless modem, but only for the wireless
connectivity of data communications. At least one manufacturer’s
cellular phone has a PDA built-in. It is immaterial
whether we choose to call it a phone with PDA or a PDA with
a phone built into it.
There is an entire class of devices devoted to wireless
mobile data. Some PDAs are primarily email devices. Others
are more generic and can run many different applications, such
as the Palm Pilot or Visor. All, however, fall into two categories:
They either use public cellular for communications or they use
other public or private networks. They all share the same limitations
for data transmission, and they are limited to the current
state of the art of the physical access channel. Except for
Ricochet, this means 19.2 Kbps or less. When they are upgraded
to next-generation cellular, data rates will increase.
One very interesting thing to watch will be the migration or
upgrade paths for the noncellular networks when competition
for higher data rates begins. Most are using 19.2 Kbps for wireless
PDA and Pocket PC communications.
not even need voice capabilities. Does you home PC have a
telephone receiver hanging on it? Of course not: The computer’s
primary function is to do meaningful data crunching!
Personal digital assistants and pocket PCs were created to
provide a certain level of support for the mobile user, which
could only previously be available on a laptop PC, but smaller
and lighter. They are not primarily voice communications
devices—they are for storage, retrieval, and manipulation of
data. Some PDAs and pocket PCs may attach to a cellular
phone or other type of wireless modem, but only for the wireless
connectivity of data communications. At least one manufacturer’s
cellular phone has a PDA built-in. It is immaterial
whether we choose to call it a phone with PDA or a PDA with
a phone built into it.
There is an entire class of devices devoted to wireless
mobile data. Some PDAs are primarily email devices. Others
are more generic and can run many different applications, such
as the Palm Pilot or Visor. All, however, fall into two categories:
They either use public cellular for communications or they use
other public or private networks. They all share the same limitations
for data transmission, and they are limited to the current
state of the art of the physical access channel. Except for
Ricochet, this means 19.2 Kbps or less. When they are upgraded
to next-generation cellular, data rates will increase.
One very interesting thing to watch will be the migration or
upgrade paths for the noncellular networks when competition
for higher data rates begins. Most are using 19.2 Kbps for wireless
PDA and Pocket PC communications.
WINCE
Windows CE is the modular real-time embedded operating system
from Microsoft. It is a scaled-down, multitasking, multithreading
look-alike of the popular Windows Operating System
designed for 32-bit devices or information appliances.
However, it does not require an Intel x86 family microprocessor.
Several manufacturers, including Compaq, are currently
marketing products using this operating system. Although it
looks similar to Windows, it does not necessarily run all
Windows applications without modifications. When applications
are run on devices other than PCs, some Windows applications
will not run at all but this does not mean that it does
not serve as a useful tool.
The most important thing to remember about WinCE is
that the interfaces run a shell that is very similar to the standard
Windows shell, with the same windowing look-and-feel
and a taskbar at the bottom that can be used to launch and
control applications. Unlike PDAs (like Palm), where a new
interface must be learned, WinCE has a familiar “look and
feel.” One major criticism, however, haunts WinCE—the large
amount of memory required.
from Microsoft. It is a scaled-down, multitasking, multithreading
look-alike of the popular Windows Operating System
designed for 32-bit devices or information appliances.
However, it does not require an Intel x86 family microprocessor.
Several manufacturers, including Compaq, are currently
marketing products using this operating system. Although it
looks similar to Windows, it does not necessarily run all
Windows applications without modifications. When applications
are run on devices other than PCs, some Windows applications
will not run at all but this does not mean that it does
not serve as a useful tool.
The most important thing to remember about WinCE is
that the interfaces run a shell that is very similar to the standard
Windows shell, with the same windowing look-and-feel
and a taskbar at the bottom that can be used to launch and
control applications. Unlike PDAs (like Palm), where a new
interface must be learned, WinCE has a familiar “look and
feel.” One major criticism, however, haunts WinCE—the large
amount of memory required.
Subscribe to:
Posts (Atom)