Cisco Cisco Catalyst 6000 Multilayer Switch Feature Card MSFC2 White Paper

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At a sporting event, for example, there are certain areas that will require ubiquitous and instant access during the

entire event. Ticketing, vendor sales, staff, and press areas will generally require the highest amount of access.

Of these, the press area is the only one that requires a high level of capacity in the arena itself. For the fans

attending the event, only a percentage will be active on the WLAN at any one time From experience we see a 20

to 30 percent take rate with some well defined peaks occurring during period breaks. During play, very few fans

are accessing the WLAN. However, this is changing as applications such as video replay, instant stats, and

concession orders from the seat become more commonplace.

Observation and understanding of the requirements of WLAN users and situational requirements will guide the

development of reasonable design goals. 500 users in a room who require simultaneous access to a single

resource is a different design challenge than 1,000 or 1,500 users who only occasionally use the wireless network.

Also, be aware that user patterns can and do change with time. This has been seen with the increase in the

number of network clients per user. Monitoring network access and keeping good statistics will allow wireless

engineers to stay on top of user trends on the university campus. Good management platforms such as Cisco

WCS or Cisco Network Control System (NCS) are essential for managing the resulting network in real time and

monitoring trends in a proactive manner.

Access Point Placement and Coverage Strategies

Often one of the biggest challenges in a high-density environment is access and aesthetics. A large meeting hall

is impressive because of its size and a great deal goes into the aesthetics of the environment. The best approach

to engineering a specific space is to do a qualified sight survey. Once the APs are mounted, physical adjustments

become a lot more complex, so it is best to test while installing and make certain that the coverage that has been

defined in the design is what is installed.

APs have evolved rapidly in short period of time. If an AP with external antenna capabilities is to be used, it is

essential that an antenna that was designed for that AP also be used. MIMO or 802.11n APs need MIMO

antennas to perform properly. Even if HT rates are not being counted on, the antenna and the radios are a system

and the system is designed to perform with all of these elements. A good overview of antennas and pattern

information can be found in

Antenna Patterns and Their Meaning

Omnidirectional Antennas Versus Directional Antennas for High-Density Coverage

Mounting APs or directional antennas directly overhead in an environment may not be acceptable to the building

owners. There are several ways to solve this problem and, depending on the environment and restrictions

imposed, several methods may be used together.

The best approach to engineering a specific space for a high-density WLAN is to first do a thorough, active site

survey to determine how and where the APs should be optimally installed. This will clarify what is possible in the

space and provide a design to work from. Any changes to the optimal placement imposed by restrictions will

require another survey because the final throughput for the space will likely change. If the environment and

requirements necessitate the use of directional antennas, remember that once the APs are mounted, physical

adjustments can become a lot more complex, depending on the mounting location. So it is best to test them while

they are being installing to ensure that the anticipated coverage results from what is installed.