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Wireless networks must overcome interference, latency and security challenges

Wireless networks "have issues with firewalls and timing concerns," one user says

By , Network World
May 05, 2009 04:51 PM ET

Network World - [Editor's note: The section of this story on Oklahoma City has been reworked to clarify information originally reported and written.]


Wireless networks bring flexibility, but IT managers say plenty of security and other considerations are necessary to make a deployment successful.

Oklahoma City, for example, for a year has operated a 620 square-mile 802.11g wireless network that now supports about 200 applications accessed by laptops, handheld devices and other endpoints by city police and fire personnel as well as other city departments such as transit and public works. As convenient and reliable as this Tropos Networks-based meshed 802.11g is, the city backs it up using Sprint mobile cards as standard operating procedure for protecting mission critical applications and to extend the range of wireless coverage since the Tropos system deployment was not designed to cover all 620 square miles. The Sprint cards can also come in handy when line-of-sight interference occurs (no significant RF interference has surfaced).

Potential latency issues associated with the 802.11-based network could have complicated Oklahoma City's security plans to transition thousands of employees from re-usable passwords to stronger token-based, two-factor authentication. Wireless networks "have issues with firewalls and timing concerns," says Steve Eaton, Oklahoma City's information security architect, noting that latency -- the time it takes a packet to reach from one designated point to another -- is slower than in wire-only networks.

So when installing the Quest Defender two-factor authentication gateway the city selected, configuration adjustments were made.

Others benefiting from the advantages of wireless say they are also cognizant of its challenges.

Since late last year, Lynchburg, Va.-based Liberty University has deployed hundreds of Aruba 802.11n wireless access points on campus, and also uses the Aruba Endpoint Compliance System (ECS) for network-access control for students.

"The vast majority of our students are now on it," says Bruce Osborne, a network engineer at the university.

Each student needs an ECS software agent, says Jimmy Graham, Liberty's manager of network services, and if any of the roughly 10,000 students lack the requisite antivirus or security patches, they're isolated from wireless access until their computers obtain required security updates, which can be done online.

The tougher challenge has been getting VoIP phones -- in this case Cisco's -- to work optimally on the wireless network. There are challenges related to latency and VoIP's high-bandwidth needs.

"We need quality-of-service to manage this," Osborne says. VoIP traffic over wireless will need to be given priority over other traffic, and until that is all sorted out, the majority of phones will remain wireline-based on the campus.

Sisters of Mercy Health System, the Hatboro, Mo.-based healthcare provider, is benefiting from IP-based phones over wireless in its installation of the Ascom IP DECT System wireless base stations and phones at a number of its hospital sites.

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