User guide

Troubleshooting Wireless Connectivity
136 Check Point ZoneAlarm User Guide
• Check the Transmission Power parameter in the WLAN's advanced settings.
• Make sure that you are not using two access points in close proximity and on the
same frequency. For minimum interference, channel separation between nearby
access points must be at least 25 MHz (5 channels).
• The ZoneAlarm router supports XR (Extended Range) technology. For best
range, enable XR mode in the wireless network's advanced settings, and use XR-
enabled stations.
• Range outdoors is normally much higher than indoors, depending on
environmental conditions.
Note: You can observe any changes in the wireless reception in the My Computers
page. Make sure to refresh the page after making a change.
Note: Professional companies are available for help in setting up reliable wireless
networks, with access to specialized testing equipment and procedures.
There are excessive collisions between wireless stations. What should I do?
If you have many concurrently active wireless stations, there may be collisions between
them. Such collisions may be the result of a "hidden node" problem: not all of the stations
are within range of each other, and therefore are "hidden" from one another. For example,
if station A and station C do not detect each other, but both stations detect and are detected
by station B, then both station A and C may attempt to send packets to station B
simultaneously. In this case, the packets will collide, and Station B will receive corrupted
data.
The solution to this problem lies in the use of the RTS protocol. Before sending a certain
size IP packet, a station sends an RTS (Request To Send) packet. If the recipient is not
currently receiving packets from another source, it sends back a CTS (Clear To Send)
packet, indicating that the station can send the IP packet. Try setting the RTS Threshold
parameter in the wireless network's advanced settings to a lower value. This will cause
stations to use RTS for smaller IP packets, thus decreasing the likeliness of collisions.
In addition, try setting the Fragmentation Threshold parameter in the wireless network's
advanced settings to a lower value. This will cause stations to fragment IP packets of a
certain size into smaller packets, thereby reducing the likeliness of collisions and
increasing network speed.