U3 Interface between WLC and CWC(Cellular WLAN Controller) 
is present to support Real-Time Traffic Steering(RTTS) of 
client between 3GPP networks and WLAN. Throughput needs to
be calculated at WLC and shared with the CWC to take decision 
to steer the traffic to WLAN or not. It is also defined to 
reject client in case if throughput is not satisfactory 
along with periodic updation of throughput.

           GLOSSARY

 Access Point ( AP )

 An entity that contains an 802.11 medium access
 control ( MAC ) and physical layer ( PHY ) interface
 and provides access to the distribution services via
 the wireless medium for associated clients.  

 LWAPP APs encapsulate all the 802.11 frames in
 LWAPP frames and sends it to the controller to which
 it is logically connected to.

 Central Controller ( CC )

 The central entity that terminates the LWAPP protocol
 tunnel from the LWAPP APs.  Throughout this MIB,
 this entity also referred to as 'controller'.

 Light Weight Access Point Protocol ( LWAPP ) 

 This is a generic protocol that defines the
 communication between the Access Points and the
 controllers.
 
 Cellular WLAN Controller ( CWC )

 A decision making entity to steer traffic over LTE or
 WLAN.