Overview
Wireless
by Chris Ludwig, Regional Director of Practice Managers
Cisco offers a variety of access points today. Here is a brief look at some of the differences between the various models:
1240 Series – The 1240 series of Cisco access points is the series that companies recommend for most implementations. The 1240 series are 802.11 a/b/g access points that support both autonomous and LWAPP mode. In addition, the 1200s will have a version of code in Q1 2006 that will support REAP (remote edge lightweight access point). REAP allows an LWAPP access point to continue service for existing wireless devices should it be unable to contact the wireless controller. Additional benefits include:
- Full diversity support
- Supports multiple roles (root bridge, non-root bridge, workgroup bridge, access point, repeater)
- External antennas selection that allows versatility in coverage patterns
- Better wall penetration
- Console port to recover software problems
- Simultaneous support of 802.11a and 802.11g/b
- Operating temperature of -4F to 131F and storage temperature of -40F to 185F
- Power options include: local power, Cisco pre-standard power, 802.11af switches, power injectors
- Supports LWAPP or autonomous models
- Native diversity support
- Internal antennas only
- Lower wall penetration compared to the 1200 series due to antenna selection
- No console port to recover if a problem is incurred
1000 Series – The 1000 series of Cisco access points support LWAPP solutions only. They are not stand-alone autonomous access points which means they will require a wireless controller in order to configure. The 1000 series has three different models of access points which are listed below. All three models support 802.11 a/b/g in a dual mode.
1010 model:
- Does not support diversity
- Does not support external antennas
- Low wall penetration compared to 1200 series
- No console port to recover if a problem is incurred
1020 model:
- Supports external antennas
- Low wall penetration compared to 1200 series
- No console port to recover if a problem is incurred
1030 model
- Supports external antennas
- Low wall penetration compared to 1200 series
- No console port to recover if a problem is incurred
- Supports REAP (ability to support CURRENT wireless clients in the case of a controller failure)
Importance and Benefits of Site Surveys
All wireless environments are never the same. The problems range from things you can see (metal shelving units, cubicles, chairs, desks etc) to things you cannot see (Background RF, Wall/Floor construction type). Until tested, all of these present unique challenges for each building. Running voice over wireless also brings some challenges that need to be taken into account when surveying for wireless. The number of clients and the RSSI value on the phones becomes very important to have good voice quality on the WLAN.
If an area is not correctly surveyed you could end up purchasing too many or too few Access Points. One of the common mis-conceptions is "I don't need a survey, I will just put up more than enough APs." The problem with that is there are only 3 non-overlapping channels in the 802.11b/g spectrum. This means that you have to correctly space them out, if you have too much overlap, you will reduce the throughput and increase errors on the wireless network. Ultimately, getting the correct coverage requires that the AP's be correctly spaced as well as the channel selections need to be correctly set. The other problem with that assumption, is the cabling. You need to have CAT5 cabling pulled to the locations of the AP's. This is normally something that is not easily moved if it is pulled to the wrong locations. So moving the AP's to a new location to solve a coverage area after implementation has taken place can be a very costly solution. One last problem becomes fixing coverage areas after you have already allowed users on the wireless network. This creates an issue with bringing down the WLAN during the correction of the problem. This causes both the IT staff and users heartache while you are trying to fix a defective wireless design.
NWN Corporation does all of our wireless projects by first performing a site survey. This survey will be conducted by wireless experts who can spot the potential issues and purpose solutions before equipment is purchased. The testing/survey is done with the same wireless equipment that NWN recommends purchasing and each location will be marked out and noted so that when the installation is done you have exactly the correct AP's/Antennas/Locations/Channel selections and power settings. We have found that this is the best way to implement wireless so it is successful the first time.
To learn more about wireless site surveys contact your NWN account manager.
