WMM addresses wireless QoS

NETWORK WORLD NEWSLETTER: NETWORKING TECHNOLOGY UPDATE
09/26/05

Dear networking.world@gmail.com,

In this issue:

* The Wi-Fi Alliance provides prioritization of data packets to
clear the way on wireless networks
* Links related to Networking Technology Update
* Featured reader resource
_______________________________________________________________
This newsletter is sponsored by Nokia
Empower Your Mobile Enterprise

Nokia believes that business mobility will fundamentally change
the way work gets done-and for the better. To allow the entire
organization to get the most from this paradigm shift in
productivity, Nokia Enterprise Solutions focuses on delivering
increased efficiency through enhanced mobility. Learn more by
downloading this white paper today!
http://www.fattail.com/redir/redirect.asp?CID=115786
_______________________________________________________________
Network World New Data Center
Spotlight on Advanced IP

Piecing Together the Next Generation IT Architecture. This 5th
installment in a 6 part series takes a look at at On-demand
services, automated management, and management technologies.
PLUS, see how two IT Execs are plotting their way to an all
IP-world. This NDC issue has it all, click here to read now,
http://www.fattail.com/redir/redirect.asp?CID=115645
_______________________________________________________________

Today's focus:

WMM addresses wireless QoS

By Ben Guderian

As audio, video and voice applications proliferate on wireless
networks, QoS mechanisms are needed to make sure applications
with low tolerance for latency and jitter are treated with
higher priority than less-sensitive data applications. QoS is
critical because wireless LANs have less bandwidth and are less
tolerant of packet collisions than wired LANs.

The IEEE is finalizing a wireless QoS standard, 802.11e , that
is expected to be approved this year. Eager to spur
interoperable QoS among different vendors' wireless gear, the
Wi-Fi Alliance developed a subset of 802.11e called the Wi-Fi
Multimedia (WMM) specification. Makers of wireless access points
as well as wireless client devices such as laptops, phones and
consumer electronics products are incorporating support for WMM
into their wares.

WMM is designed to support consumer and corporate applications
and works with all three 802.11 wireless physical layer
standards - 802.11a, 802.11b and 802.11g. The specification
provides basic prioritization of data packets based on four
categories - voice, video, best effort and background. In its
current form, WMM doesn't provide mechanisms for scheduling or
controlling network access to improve QoS, but these
enhancements may be added in future releases.

Prioritization is based on the original Carrier Sense Multiple
Access/Collision Avoidance Protocol in the initial 802.11
standard. A mechanism called Distributed Coordination Function
(DCF) uses a simple listen-before-talk algorithm to minimize the
chance of packet collisions caused by more than one device
accessing the wireless medium at the same time. A client must
wait for a randomly selected time period and then "listen" to
find whether any other device is communicating before starting
to transmit. The random back-off period gives all devices a fair
opportunity to transmit.

However, WMM stipulates different fixed and random wait times
for the four prioritization categories to provide more favorable
network access for applications that are less tolerant of packet
delays. Devices that have less time to wait have a better chance
of being able to transmit than those that have a longer wait. In
order of highest priority, the access categories are voice,
video, best effort and background. These WMM prioritization
categories map to Ethernet 802.1d prioritization tags to allow
consistent QoS across wireless and wired network segments.

To read more, please see:
<http://www.networkworld.com/nltechupdate7589>

The top 5: Today's most-read stories

1. McAfee, Omniquad top anti-spyware test
<http://www.networkworld.com/nltechupdate6919>

2. IT pros share their tales of making ITIL work
<http://www.networkworld.com/nltechupdate7689>

3. The rise of the IT architect
<http://www.networkworld.com/nltechupdate7022>

4. Wireless: Volunteers give voice to evacuees
<http://www.networkworld.com/nltechupdate7690>

5. How to solve Windows system crashes in minutes
<http://www.networkworld.com/nltechupdate7691>

_______________________________________________________________
To contact:

Guderian is vice president of Market Strategies and Industry
Relations for SpectraLink. He can be reached at
bguderian@spectralink.com
_______________________________________________________________
This newsletter is sponsored by Nokia
Empower Your Mobile Enterprise

Nokia believes that business mobility will fundamentally change
the way work gets done-and for the better. To allow the entire
organization to get the most from this paradigm shift in
productivity, Nokia Enterprise Solutions focuses on delivering
increased efficiency through enhanced mobility. Learn more by
downloading this white paper today!
http://www.fattail.com/redir/redirect.asp?CID=115785
_______________________________________________________________
ARCHIVE LINKS

Technology Update archive:
http://www.networkworld.com/news/tech/index.html
_______________________________________________________________
FEATURED READER RESOURCE

The Trend Micro Threat Map

The Trend Micro Threat Map dynamically displays real-time data
to show worldwide trends in virus and content security threats
as they happen. Collected from actual computer infections, the
Threat Map can be used to help determine appropriate security
policies, based on the prevalence of threats that can adversely
affect your business.

<http://www.networkworld.com/go/trendmicro/trend_frr>
_______________________________________________________________
May We Send You a Free Print Subscription?
You've got the technology snapshot of your choice delivered
at your fingertips each day. Now, extend your knowledge by
receiving 51 FREE issues to our print publication. Apply
today at http://www.subscribenw.com/nl2

International subscribers click here:
http://nww1.com/go/circ_promo.html
_______________________________________________________________
SUBSCRIPTION SERVICES

To subscribe or unsubscribe to any Network World e-mail
newsletters, go to:
<http://www.nwwsubscribe.com/Changes.aspx>

To change your e-mail address, go to:
<http://www.nwwsubscribe.com/ChangeMail.aspx>

Subscription questions? Contact Customer Service by replying to
this message.

This message was sent to: networking.world@gmail.com
Please use this address when modifying your subscription.
_______________________________________________________________

Have editorial comments? Write Jeff Caruso, Newsletter Editor,
at: <mailto:jcaruso@nww.com>

Inquiries to: NL Customer Service, Network World, Inc., 118
Turnpike Road, Southborough, MA 01772

For advertising information, write Kevin Normandeau, V.P. of
Online Development, at: <mailto:sponsorships@nwfusion.com>

Copyright Network World, Inc., 2005