Chapter 8: Wds - Wireless Distribution Service; Summit Wm Lan Wds Solution Overview - Extreme Networks Summit WM Technical Reference Manual

8 WDS – Wireless Distribution Service
For 802.11, the Distribution Service (DS) is what connects APs in a wireless network. The Wireless
Distribution Service (WDS) is a feature that allows an AP to connect via the wireless medium to another
AP and use this wireless link instead of the Ethernet link to connect to the controller and the network
infrastructure. In WDS terminology, the AP that uses the WDS link to access the network infrastructure
is the child in that particular WDS link, and the AP that provides access to the infrastructure is the
parent in that particular WDS link. In general, the same AP can be a child for one WDS link and a
parent for another WDS link, which means that the WDS links can be cascaded. A parent may serve
more than one child, but each child has only one parent, hence the naming. All APs linked together by
WDS links operating on the same channel form what it is called a WDS tree. The AP that is a parent to
at least another AP but it is not a child to any AP is called the root of the WDS tree. The root provides
access to the wired infrastructure and to the controller for all APs in the WDS tree. An AP that is both
child and parent is called a repeater AP, while an AP that is only a child is called a satellite.

Summit WM LAN WDS solution overview

Dedicating a radio for WDS is not necessary — the radio used for WDS can also be used to provide
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normal user access. However, if needed, the user can reserve one radio only for WDS backhaul in
order to achieve much better performance.
Every member of the WDS tree — root, repeater, or satellite — can support normal AP operation on
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the same radio used for WDS.
The WDS feature is completely integrated into the Summit WM framework and supports most of its
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features (for example, multiple WM-AD per radio, availability, WPAv1/v2, WMM/11e, all WM-AD
types: bridged at AP, routed and bridged at WM) with only certain exceptions (for example,
intrusion detection, DRM) detailed below.
The VLAN tagging/de-tagging for bridged at AP WM-ADs as well as the WASSP encapsulation/de-
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capsulation for the tunneled WM-AD are performed at the AP to which the client is associated.
Therefore, the Extreme Networks WDS provides only transparent transport without the need to
know about all the WM-ADs that it transports. As a result:
Each AP in a WDS tree can be configured with a different set of WM-ADs.
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With the exception of the size of the MAC address table in the L2 bridge, there are no other
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processing requirements that increase with the complexity of the WDS tree.
WDS supports (as a configurable option) wireless bridging of the Ethernet traffic from satellite or
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repeater APs.
The WDS WM-AD is conveniently managed via the controller's GUI — the Summit WM Graphical
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User Interface (GUI).
The vehicle used to configure WDS, is a WM-AD, thus allowing multiple WDS networks to coexist
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on the same network and even on the same AP. Each WDS WM-AD can be used to configure one or
more WDS trees on a single channel but also on different 11a and 11b/g channels. However, It is
recommended to use a separate WM-AD per each tree whenever possible.
The same AP may be a member of multiple WDS WM-ADs. The same AP can be configured with
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different roles in each WDS WM-AD (for example, child in one WDS WM-AD and a parent in the
other) but also with the same role (for example, child for both WDS WM-ADs). If configured so, the
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