Extreme Networks Summit WM Technical Reference Manual page 95

connects again to a controller. However, if a repeater AP with link persistence enabled loses its WDS
uplink — its link to its parent — the repeater AP disconnects its own children in order to scan all
channels for a new parent.
Mode persistent is not supported in conjunction with WDS because the WDS child APs must first
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connect to the controller in order to offer any service.
WDS and parent availability
If during scanning the WDS child AP does not find its preferred parent, it will connect to the back-
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up parent, if available, or it will continue searching for a parent, if neither of the parents are
available.
If a WDS child AP loses its uplink connection to its current parent (either preferred or back-up), it
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will stop service, then scan for parents and connect to the preferred parent, if found, or otherwise to
the back-up parent.
WDS and QoS
The WDS feature provides transparent transport of the frames and therefore preserves the L2 and L3
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QoS tagging. The packets are prioritized on the WDS links according to their 802.1p L2 tags.
In the downlink direction, the QoS tags are as received from the wired infrastructure.
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In the uplink direction, the QoS tags are set by the satellite or repeater AP that received the
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frame, according to the QoS settings for the WM-AD to which the client belongs.
The Admission Control (TSPEC) feature is fully supported on WDS APs. However, the bandwidth
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allocation is performed only for the AP to which the client is associated and it is not performed for
the repeaters and the root through which the admitted stream will travel. To overcome this
limitation, it is recommended to use a dedicated radio (typically 11a) for WDS links only.
WDS security
The WDS links support only the strongest encryption. For example, AES.
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The WDS parents ignore probe requests, authentication requests, and association requests from
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normal clients on the WDS WM-AD. Normal clients cannot connect to the WDS WM-AD.
WDS bridge
If the WDS bridge option is enabled on a satellite or repeater AP, the Ethernet port of that AP will be
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bridged to the Ethernet port of the root.
If the wireless bridge option is enabled on multiple WDS satellite or repeater APs, the Ethernet ports
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of those APs will be bridged together with the Ethernet port of the root.
The WDS bridge implements all packet forwarding rules as any other L2 switch, but no GARP, STP,
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etc.
The WDS bridge is transparent to 802.1q VLAN tags, but it does not restrict forwarding of
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broadcasts/multicasts or packets with unknown destinations based on the VLAN tag.
The WDS bridge preserves both L2 and L3 QoS tags. The packets are prioritized based on the their
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802.1p L2 tags.
Summit WM Technical Reference Guide, Software Version 5.1
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