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Speeding on 802.11n
 Speed,
or lack of it, has always deterred CIOs from large scale Wi-Fi adoption. However,
once 802.11n specifications are ratified by IEEE, wireless networks will blaze
at speeds of more than 100 Mbps in 2006. The latest EWC proposal promises Wi-Fi
speeds as high as 600 Mbps. by Kumar Dawada
The worst thing about a new technology is when it promises the moon, but fails
to deliver according to expectations. This has so far been the case with Wi-Fi.
Ever since IEEE (Institute of Electrical and Electronics Engineering) developed
IEEE 802.11 in 1997, a major bottleneck in its adoption by enterprises has been
the slow data throughput. It also had its share of other problems including
easily penetrable security and health concerns.
Impending Revolutions
802.11n, Wi-Fi’s high-speed next generation standard,
promises to resolve at least two major issues—speed and security. 802.11n
adds multiple-input multiple-output (MIMO) and orthogonal frequency division
multiplexing (OFDM) to the previous 802.11 standards. See Box: Tiding over Wi-Fi
security glitches for more details on known Wi-Fi security issues and proposed
solutions.
| MIMO (Multiple Input Multiple Output) is a technique
of transmitting data by using multiple signal paths (first conceptualised
in 1985). It uses multipath signal propagation to increase throughput, or
reduce bit error rates instead of attempting to eliminate effects of multipath.
In 1996, Airgo Networks introduced new approaches to MIMO called MIMO OFDM
(Orthogonal Frequency-Division Multiplexing) to increase its efficiency.
Airgo is the leader in MIMO products. It is the
only company currently producing the MIMO chips. Intel and Broadcom are
unable to produce MIMO chips because they committed not to produce or
market the pre 802.11n standardisation chips. Delay can only help Airgo
become a de facto MIMO standard.
According to Airgo, in simple terms MIMO means transmitting
two or more unique radio signals in the same radio channel. Each signal
carries different digital information. MIMO is the backbone technology
of 802.11n. OFDM is a transmission technique based on FDM (Frequency Division
Multiplexing). In FDM, multiple signals are sent out at the same time,
but on different frequencies. In OFDM, a single transmitter transmits
on many different orthogonal (independent) frequencies. This modulation
technique results in a signal which is resistant to interference.
OFDM is used along with channel coding (an error
correction technique) to create coded orthogonal FDM. The system is used
in broadcasting and computer networking technology because such signals
show resistance to multipath fading.
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Tiding Over Wi-Fi Security Glitches
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Satyen Naik
Assistant Manager-IS
Sumul Dairy
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Satyen Naik, Assistant Manager, IS, Sumul Dairy feels that
802.11n will find application in all major verticals. “It will be a boon
to business and enterprises which cover a large geographical area, especially
remote areas. Some day wireless network will replace all leased lines, VSAT,
ISDN solutions and the entire wired network architecture because these have
deployment hurdles as well as high recurring maintenance costs. High speed WLAN
technology such as 802.11n will be the cheapest and easiest solution to deploy,”
says Naik.
| From 2001 onwards, weaknesses were exposed in 802.11
WEP (wired equivalent of privacy), the security mechanism defined in the
original 802.11 standard. AT&T had verified attacks. Black hat hackers
were able to intercept transmissions and gain unauthorised access to wireless
networks.
It was clearly demonstrated at this time that Wi-Fi
equipment could be used to steal personal information such as passwords
transmitted from Wi-Fi users, if proper protections are not used. It was
shown that WEP can be breached easily even when it is configured correctly.
As a result, the wireless products in the market supported the stronger
Wi-Fi Protected Access (WPA) encryption protocol.
Even today, many large corporations with sensitive
customer information, especially in BFSI sector, are reluctant to deploy
Wi-Fi solutions. This causes security risks in a network by allowing an
unauthorised wireless access point (rogue access point). Wireless routers
allow employees to connect an unauthorised access point out of ignorance
or malice. This exposes the secure corporate network to anyone who is
wardriving. To reduce the risk of rogue access points large organisations
install wireless intrusion detection systems to monitor the premises for
wireless signals and immediately report any unauthorised access points.
The IEEE set up a dedicated task group to create
802.11i (WPA2) for enhancing security It was ratified in June 2004 and
uses advanced encryption standard. In January 2005, IEEE set up a task
group to create 802.11w to protect management and broadcast frames, which
so far were sent unsecured.
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Genesis Of N
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Some day wireless network will replace all leased lines,
VSAT, ISDN solutions and the entire wired network architecture because
these have deployment hurdles as well as high recurring maintenance costs.
High speed WLAN technology such as 802.11n will be the cheapest and easiest
solution to deploy
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IEEE formed a new 802.11 Task Group (TGn) to develop 802.11n
standard for WLAN in January 2004. The real data throughput is estimated to
reach 540 Mbps.
In July 2005 competitors TGnSync and WWiSE (See Box: Players
involved in 802.11n standardisation for more details on TGnSync and WWiSE) agreed
to merge their proposals as a draft and send it to the IEEE in September 2005.
They also agreed to submit a final version in November so that the standardisation
process could be completed by the second half of 2006.
| IEEE 802.11 TGn: This is the group responsible
for setting the 802.11n standard specifications.
WWise (World-Wide Spectrum Efficiency): Leading
the WWiSE group is Airgo Networks, the chief proponent of MIMO. WWiSE
also has the support of Texas Instruments, Broadcom, Conexant, AT&T,
Motorola, Nokia, HP, Siemens and others.
TGnSync: Its members includes Cisco, Hitachi,
Infineon, Intel, Marvell, MetaLink, Mitsubishi, Nortel, Panasonic, Qualcomm,
Philips, Samsung, SANYO, Sharp, Sony, Toshiba, Via, and others.
Joint Proposal team: The JP Team consists
of 42 companies that are part of the TGn Synch, and WWiSE groups of companies.
The target for the JP team is to deliver a final Joint Proposal to the
802.11n Task group at the November IEEE meeting in Vancouver, Canada.
EWC (Enhanced Wireless Consortium): Its members
are Wi-Fi industry leaders including Intel, Atheros, Broadcom, Marvell,
Cisco, D-Link, Linksys, Netgear, US Robotics, Apple, Lenovo, Sony, Toshiba
and others.
Wi-Fi Alliance: IEEE sets standards. It does
not test equipment for compliance with the standards. Wi-Fi Alliance is
a trade group which provides Wi-Fi certification to the companies selling
802.11 equipment. The Wi-Fi trademark can be used only on compliant equipment
and it is intended to guarantee interoperability.
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802.11n: So Near Yet So Far
Until recently the 802.11 TGn (Task Group n) entrusted with ratifying the 802.11n
standard was split into two groups WWiSE and TGn Sync. If none of them gets
the 75 percent majority to enable their proposal to be accepted as the draft
standard then the selection process will start all over again at the next meeting
in January 2006. This might delay 802.11n specification from being standardised
until mid 2007.
To prevent this, the groups agreed to work together on a joint
proposal by forming a JP (Joint Proposal) Team. Its target was to deliver a
final Joint Proposal to the 802.11n Task group at the November IEEE meeting.
Now a new group called EWC (Enhanced Wireless Consortium) has also been formed.
They claim that the JP Team does not have a joint proposal yet. EWC’s goal
is to speed up the introduction of the new wireless standard and promote a technology
specification for next generation WLAN products. Their proposal offers Wi-Fi
speed of 600 Mbit/s.
| The IEEE TGe (Task Group e) has recently finalised
the 802.11e standardisation. It enhances the MAC (media access control)
layer of 802.11 chips. As a result, wireless networks provide better performance
for VoIP and multimedia applications. The 802.11e standard aims at improving
video, audio and voice traffic on wireless networks. |
The Indian Take
Ranajoy Punja, Vice-president, Marketing, Cisco Systems feels that Indian enterprise
has warmed up to wireless networking due to 802.11 a, b and g standards. They
offer sufficient performance with existing wireless applications. “802.11n
will deliver a minimum throughput of 100 Mbps. Enterprises will have the flexibility
to extend the use of wireless networks to areas not reachable with wired systems,”
says Punja.
However, Rajendra Dhavale, Consulting Director, Computer Associates is cautious
about implementation of 802.11n. He feels that more than technology, compatibility
is a major issue. “The standards are yet to be drafted by IEEE. Vendors
have already started shipping ‘pre-n’ devices which use MIMO technology.
However, they cannot be fully compliant with 802.11n specifications as there
is no defined standard yet. This will create compatibility issues when the actual
standard is set and released,” says Dhavale.
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Suresh Shenoy
Vice-president - IT
Wockhardt
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Suresh Shenoy, Vice-president – IT, Wockhardt feels that
the healthcare and manufacturing verticals will benefit the most from high speed
wireless networking. “Handhelds and portable devices will dominate the
communications scenario. The technology will have a significant impact on all
industry verticals where time is critical. It will be ideal for professionals
like doctors, especially during medical emergencies and in the course of post
operative treatment,” says Shenoy.
Due to the high level of throughput it will deliver, 802.11n is likely to be
used beyond traditional enterprise and home environments. This will encompass
areas such as cellular telephony, mobile radio and VoIP. In 2006, we ought to
see many industries adapting wireless technology for their mobile staff.
However, the bottom line is that no amount of standardisation will resolve
all issues. They can only help improve product efficiency but the actual design
and manufacturing issues alone will decide the performance of the final product.
kumard@networkmagazineindia.com
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