This MIB is intended to be implemented on all those
devices operating as Central controllers, that
terminate the Light Weight Access Point Protocol
tunnel from Cisco Light-weight LWAPP Access Points.

Network management stations learn the audio/video
traffic quality observed on WLANs through this MIB.

The relationship between CC and the LWAPP APs
can be depicted as follows:

      +......+     +......+     +......+
      +      +     +      +     +      +
      +  CC  +     +  CC  +     +  CC  +
      +      +     +      +     +      +
      +......+     +......+     +......+
        ..            .             .
        ..            .             .
       .  .            .             .
      .    .            .             .
     .      .            .             .
    .        .            .             .
+......+ +......+     +......+      +......+
+      + +      +     +      +      +      +
+  AP  + +  AP  +     +  AP  +      +  AP  +
+      + +      +     +      +      +      +
+......+ +......+     +......+      +......+
           .              .             .
         .  .              .             .
        .    .              .             .
       .      .              .             .
      .        .              .             .
   +......+ +......+     +......+      +......+
   +      + +      +     +      +      +      +
   +  MN  + +  MN  +     +  MN  +      +  MN  +
   +      + +      +     +      +      +      +
   +......+ +......+     +......+      +......+


The LWAPP tunnel exists between the controller and
the APs.  The MNs communicate with the APs through
the protocol defined by the 802.11 standard.

LWAPP APs, upon bootup, discover and join one of the
controllers and the controller pushes the configuration,
that includes the WLAN parameters, to the LWAPP APs.
The APs then encapsulate all the 802.11 frames from
wireless clients inside LWAPP frames and forward
the LWAPP frames to the controller.

This MIB provides the information about the per-client
/per-AP packet latency, packet jitter, packet loss and
roaming time in the network which does affect quality 
of audio/video traffic. These parameters are called 
Traffic Stream Metrics. When TSM collection is enabled 
on all 802.11a/802.11b interfaces, the metrics are 
collected by controller from AP in every 90 seconds 
window.

	Information provided by this MIB can be used by the
NMS applications to present measurements of audio and 
video traffic quality. 

                   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.

Central Controller ( CC )

The central entity that terminates the LWAPP protocol
tunnel from the LWAPP APs.  Throughout this MIB,
this entity is 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
Central Controller.

Mobile Node ( MN )

A roaming 802.11 wireless device in a wireless
network associated with an access point.

Traffic Stream Metrics (TSM)

These  are parameters like the per-client / per-AP
packet latency, packet jitter, packet loss and roaming
time in the network, which does affect quality of
audio/video traffic.  These statistics are collected
to study and characterize the pattern of data
traffic and perform appropriate management tasks to
regulate the same for the smooth functioning of the
network. 

Channel Utilization (CU)
The Channel Utilization is defined as the percentage of time,
the QAP sensed the medium was busy, as indicated by
either the physical or virtual carrier sense (CS) mechanism.

Picc
Picc is the time consumed by AP for receiving frames
not destined to itself on a particular Radio interface
from co-channel APs and Clients.

Pib
Pib is the time consumed by AP for receiving frames on 
a particular Radio interface which are not correctly de-modulated.
                       
REFERENCE

[1] Wireless LAN Medium Access Control ( MAC ) and
Physical Layer ( PHY ) Specifications.

[2] Draft-obara-capwap-lwapp-00.txt, IETF Light 
Weight Access Point Protocol