H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 337)

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WLAN Roaming Configuration
The sample output in this manual was created on the WX5004. The output on your device may
vary.
The grayed out functions or parameters on the Web interface indicate that they are not supported
or cannot be modified.
The models listed in this manual are not applicable to all regions. Please consult your local sales
office for the models applicable to your region.
WLAN Roaming Overview
The Inter AC Tunneling Protocol (IACTP) is a tunneling protocol of H3C which defines how access
controllers (ACs) communicate with each other. IACTP provides a generic encapsulation and transport
mechanism between ACs to provide secure AC-AC communications based on the standard TCP
client/server model.
A mobility group is a group of ACs that communicate with each other using the IACTP protocol. A
maximum of 8 ACs can be present in a mobility group in current version. Formation and maintenance of
a mobility group is done using IACTP.
IACTP provides a control tunnel for applications such as roaming to share/exchange messages. It also
provides a data tunnel to encapsulate data packets to be transported between ACs. It can be used
either with IPv4 or with IPv6.
Whenever a station supporting key caching associates to any of the ACs in a mobility group (which
would be it’s Home-AC (HA)) for the first time, it will go through 802.1X authentication followed by 11
Key exchange. The station information will be synchronized across the ACs in the mobility group prior to
the roaming of the station within an AC/across ACs. When this station roams to another AC in the
mobility group (which would be its Foreign-AC (FA)), the station information is used to fast authenticate
the station by skipping 802.1X authentication, and performing only 802.11 key exchange to facilitate
seamless roaming within the mobility group.
Terminology
HA: The AC to which a wireless station is connected by associating with an AP for the first time is
the HA of the station.
FA: An AC that is other than the HA and to which a station is currently connected is an FA of the
station.