NDC comm Instant Wave - Manual (Page 13)

Roaming
InstantWave High Rate products are equipped with seamless roaming capabilities.
Roaming is necessary to prevent mobile Stations from being disconnected from the
network as they move around.
InstantWave High Rate is designed to 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 6)
b) The APs must be configured to have the same Domain name (see AP
COMFig Service, page13)
c) The mobile Stations must have the same Domain name as that of the APs
d) *It is advisable that APs on different TCP/IP subnets be given different
Domain names to avoid roaming confusion (seeAP COMFig Service ,
page13)
Note: If you want to move your mobile PC between different APs without
terminating the existing networking link, you need to enable the roaming
function on the Mobile Station. The APs that a Mobile Station will roam to
must also be configured with the same domain name. If a Station detects
that the signal quality with the current linked AP is weak, it will search for
an AP in the same domain with a better signal quality and automatically
establish a new connection with it. When a Station is roaming, it will
always use the same IP address. The TCP/IP router will not route
information packets to a Mobile Station if it re-associates with a AP that is
in 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 fail to communicate with other
network devices via TCP/IP. To avoid running into such an awkward
situation, you must assign different domain names to different TCP/IP
subnets.
InstantWave High Rate Access Point 7