H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 19)

7
Other related procedures
1. De-authentication
A de-authentication frame can be sent by either an AP or wireless client to break an existing link.
In a wireless system, de-authentication can occur due to many reasons, such as:
{
Receiving an association/disassociation frame from a client which is unauthenticated.
{
Receiving a data frame from a client which is unauthenticated.
{
Receiving a PS-poll frame from a client which is unauthenticated.
2. Dissociation
A dissociation frame can be sent by an AP or a wireless client to break the current wireless link. In
the wireless system, dissociation can occur due to many reasons, such as:
{
Receiving a data frame from a client which is authenticated and unassociated.
{
Receiving a PS-Poll frame from a client which is authenticated and unassociated.
IEEE 802.11 overview
The WLAN-MAC primarily includes the implementation of IEEE 802.11 MAC layer functionality. Various
modes of MAC are:
• Local-MAC Architecture
• Split-MAC Architecture
In local-MAC architecture, most WLAN services are provided by the AP only. Currently, local-MAC
architecture is not supported.
In split-MAC architecture, the AP and the AC manage different services.
AC-AP tunnel overview
An AC and AP communicate with each other over an AC-AP tunnel. The AC-AP tunnel uses a generic
encapsulation and transport mechanism, as shown in Figure 5 .
Figure 5 AC-AP tunnel
The AC-AP tunnel is built on a standard client/server model and employs UDP. Data packets to be sent
to the AC are encapsulated, and these packets can be raw 802.11 packets. Remote AP configuration and
management, and WLAN and mobile management are also supported.
The AC-AP tunnel supports both IPv4 and IPv6.
AC-AP tunnel link backup
Dual link establishment
To achieve AC backup, an AP can establish two tunnels with two ACs that must have the same AP
configurations. Only the AC which works in master mode provides services to all the APs in the network