Cisco Systems OL-6415-04 manual Payload-encapsulation, Snap dot1h

Chapter 2 Configuring Radio Settings

Enabling and Disabling Reliable Multicast to Workgroup Bridges

Beginning in privileged EXEC mode, follow these steps to configure the encapsulation transformation method:

	Command	Purpose
Step 1
	configure terminal	Enter global configuration mode.
Step 2
	interface dot11radio { 0 1 }	Enter interface configuration mode for the radio interface. The
		2.4-GHz radio is radio 0, and the 5-GHz radio is radio 1.
Step 3
	payload-encapsulation	Set the encapsulation transformation method to RFC1042
	snap dot1h	(snap) or 802.1h (dot1h, the default setting).
Step 4
	end	Return to privileged EXEC mode.
Step 5
	copy running-config startup-config	(Optional) Save your entries in the configuration file.

Enabling and Disabling Reliable Multicast to Workgroup Bridges

The Reliable multicast messages from the access point to workgroup bridges setting limits reliable delivery of multicast messages to approximately 20 Cisco Access Point Workgroup Bridges that are associated to the wireless device. The default setting, disabled, reduces the reliability of multicast delivery to allow more workgroup bridges to associate to the wireless device.

Access points and bridges normally treat workgroup bridges not as client devices but as infrastructure devices, like access points or bridges. Treating a workgroup bridge as an infrastructure device means that the wireless device reliably delivers multicast packets, including Address Resolution Protocol (ARP) packets, to the workgroup bridge.

The performance cost of reliable multicast delivery—duplication of each multicast packet sent to each workgroup bridge—limits the number of infrastructure devices, including workgroup bridges, that can associate to the wireless device. To increase beyond 20 the number of workgroup bridges that can maintain a radio link to the wireless device, the wireless device must reduce the delivery reliability of multicast packets to workgroup bridges. With reduced reliability, the wireless device cannot confirm whether multicast packets reach the intended workgroup bridge, so workgroup bridges at the edge of the wireless device's coverage area might lose IP connectivity. When you treat workgroup bridges as client devices, you increase performance but reduce reliability.

Note This feature is best suited for use with stationary workgroup bridges. Mobile workgroup bridges might encounter spots in the wireless device's coverage area where they do not receive multicast packets and lose communication with the wireless device even though they are still associated to it.

A Cisco Access Point Workgroup Bridge provides a wireless LAN connection for up to eight

Ethernet-enabled devices.

This feature is not supported on the 5-GHz radio.

Cisco Wireless ISR and HWIC Access Point Configuration Guide

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