Roaming
InstantWave products allow wireless stations to roam freely within an infrastructure domain composed of multiple APs with overlapping signal coverage (as in the Type 3 network configuration described in the previous section). For example, roaming enables Station 1 to move from the AP 1 signal coverage area to the AP 2 signal coverage area without disconnecting from the network. The handover is achieved transparently; the Station 1 user would not realize he had moved from AP 1 to AP 2.
The requirements for a roaming environment are:
a)Multiple APs with overlapping signal coverage (see “Multiple AP Installation,” page 18)
b)The APs must be configured to have the same domain name (SSID) and security (WEP) settings (see “Encryption,” page 27).
c)The mobile stations must have the same domain name (SSID) and security (WEP) settings as the APs.
It is advisable that APs on different TCP/IP subnets be given different domain names to avoid roaming confusion (see the note below).
Note: For a mobile station to move between APs without losing its network link, the Roaming function must be enabled on the station, and the APs that the station roams to must be configured with the same domain name. If a station detects that the signal quality on the link to the current AP is poor, it will search for an AP in the same domain with better signal quality and automatically associate (establish a connection) with it. The station’s IP address, however, will not change. A TCP/IP router will not route packets to a mobile station that has associated with an AP on a different TCP/IP subnet. In other words, if your network consists of two subnets connected by a router, a mobile station may roam to a different subnet with the same domain name and then be unable to communicate with other network devices via TCP/IP. To avoid this problem, you must assign different domain names to different TCP/IP subnets.
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