A wireless local access network service set identifier (WLAN SSID) is a name that identifies a specific wireless network. The WLAN SSID allows users to recognize a specific network from a list and provides a simple method for humans to remember network names. Typically, a WLAN SSID is broadcast from a wireless access point such as a router. The broadcasts may be turned off, but then only people aware of the WLANs existence may log in.
A WLAN SSID is the primary method most users use for locating a wireless access point. On most computers with wireless capabilities, the SSIDs appear in a list of available connections. Each of the names on that list is a broadcast SSID from some local access point.
There are certain specifications and conventions for a WLAN SSID. The only true restriction is that they need a name that is 32 characters or less. There are certain characters that are and are not allowed, but most of the American Standard Code for information interchange (ASCii) letters are allowed, along with a selection of symbols. Since a WLAN SSID is almost exclusively for human use, many people use only human-readable characters, although there are a handful of allowed non-readable characters.
Another common convention is uniqueness in naming. While two SSIDs may share the same name, it is rare that two in the same area have the same name. The reason for this is mostly for convenience. While a computer with auto-logon will know the difference between the two and only log on to the correct one, anytime a human needs to look at the SSID list, he won’t know which to use until after he attempts to logon.
The only common exception to this is when a single network has multiple access points. In this case, each wireless access point will likely broadcast the same SSID. A similar thing happens on a virtual network, where a single LAN may have multiple independent LANs operating on the same hardware. These names often run in sequence or on operational basis. For instance, CorpLAN1 and CorpLAN2 would be for sequential networks, and CorpMarket and CorpResearch would be operational ones.
Most access points allow the user to turn off the broadcast of the WLAN SSID. Depending on the system broadcasting and the system receiving, this will have two different results. Either the network won’t appear at all, or it will appear as an ‘Unnamed Network.’ In order for anyone to log in, he would need to know the network’s SSID.
While many users feel this gives additional security to the network, it actually does not. This will prevent unwanted access from people that would likely not be able to bypass normal security. For a person with knowledge of SSIDs and access points, turning off the broadcast is more of an annoyance than a hindrance.