User's Guide

Table Of Contents
Overview of the HiPath Wireless Controller, Access Points and Convergence Software solution
hwc_intro.fm
HiPath Wireless Controller, Access Points and Convergence Software and your network
9034530-02, March 2010
36 HiPath Wireless Controller, Access Points and Convergence Software V7.11, User Guide
2.3.7 Network availability
The HiPath Wireless Controller, Access Points and Convergence Software
solution provides availability against Wireless AP outages, HiPath Wireless
Controller outages, and even network outages. The HiPath Wireless Controller in
a VLAN bridged topology can potentially allow the user to retain the IP address
in a failover scenario, if the VNS/VLAN is common to both controllers. For
example, availability is provided by defining a paired controller configuration by
which each peer can act as the backup controller for the other's APs. APs in one
controller are allowed to failover and register with the alternate controller.
If a HiPath Wireless Controller fails, all of its associated Wireless APs can
automatically switch over to another HiPath Wireless Controller that has been
defined as the secondary or backup HiPath Wireless Controller. If the AP reboots,
the original HiPath Wireless Controller is restored. The original HiPath Wireless
Controller is restored if it is active. However, active APs will continue to be
attached to the failover controller until the administrator releases them back to the
original home controller.
2.3.8 Quality of Service (QoS)
HiPath Wireless Controller, Access Points and Convergence Software solution
provides advanced Quality of Service (QoS) management to provide better
network traffic flow. Such techniques include:
WMM (Wi-Fi Multimedia) – WMM is enabled per WLAN service. The HiPath
Wireless Controller provides centralized management of the AP features. For
devices with WMM enabled, the standard provides multimedia
enhancements for audio, video, and voice applications. WMM shortens the
time between transmitting packets for higher priority traffic. WMM is part of
the 802.11e standard for QoS. In the context of the HiPath Wireless Solution,
the ToS/DSCP field is used for classification and proper class of service
mapping, output queue seselectin, and priority tagging.
IP ToS (Type of Service) or DSCP (Diffserv Codepoint) – The ToS/DSCP
field in the IP header of a frame indicates the priority and class of service for
each frame. The IP TOS and/or DSCP is maintained and transported within
CTP (CAPWAP Tunneling Protocol) by copying the user IP QoS information
to the CTP header—this is referred to as Adaptive QoS.
Rate Control – Rate Control for user traffic can also be considered as an
aspect of QoS. As part of Policy definition, the user can specify (default)
policy that includes Ingress and Egress rate control. Ingress rate control
applies to traffic generated by wireless clients and Egress rate control applies
to traffic targeting specific wireless clients. The bit-rates can be configured as
part of globally available profiles which can be used by any particular
configuration. A global default is also defined.