User's Manual Part 1

ZyXEL G-220F User’s Guide
Wireless LAN Network 2-5
2.2 Wireless LAN Security
Wireless LAN security is vital to your network to protect wireless communications.
Configure the wireless LAN security using the Configuration or the Profile Security Settings screen. If
you do not enable any wireless security on your ZyXEL G-220F, the ZyXEL G-220F’s wireless
communications are accessible to any wireless networking device that is in the coverage area.
2.2.1 Data Encryption with WEP
WEP (Wired Equivalent Privacy) encryption scrambles all data packets transmitted between the ZyXEL G-
220F and the AP or other wireless stations to keep network communications private. Both the wireless
stations and the access points must use the same WEP key for data encryption and decryption.
There are two ways to create WEP keys in your ZyXEL G-220F.
• Automatic WEP key generation based on a “password phrase” called a passphrase. The passphrase
is case sensitive. You must use the same passphrase for all WLAN adapters with this feature in the
same WLAN.
For WLAN adapters without the passphrase feature, you can still take advantage of this feature by
writing down the four automatically generated WEP keys from the Security Settings screen of the
ZyXEL Utility and entering them manually as the WEP keys in the other WLAN adapter(s).
• Enter the WEP keys manually.
Your ZyXEL G-220F allows you to configure up to four 64-bit, 128-bit or 256-bit WEP keys and only one
key is used as the default key at any one time.
2.3 Fragmentation Threshold
A Fragmentation Threshold is the maximum data fragment size (between 256 and 2432 bytes) that can be
sent in the wireless network before the ZyXEL G-220F will fragment the packet into smaller data frames.
A large Fragmentation Threshold is recommended for networks not prone to interference while you
should set a smaller threshold for busy networks or networks that are prone to interference.
If the Fragmentation Threshold value is smaller than the RTS/CTS Threshold value (see previously)
you set then the RTS (Request To Send)/CTS (Clear to Send) handshake will never occur as data frames
will be fragmented before they reach RTS/CTS Threshold size.
2.4 RTS/CTS Threshold
A hidden node occurs when two stations are within range of the same access point, but are not within range
of each other. The following figure illustrates a hidden node. Both stations are within range of the access
point (AP) or wireless gateway, but out-of-range of each other, so they cannot “hear” each other, that is
they do not know if the channel is currently being used. Therefore, they are considered hidden from each
other.