Cisco Cisco Aironet 350 Mini-PCI Wireless LAN Client Adapter Guia Do Desenho
C H A P T E R
6-1
Enterprise Mobility 4.1 Design Guide
OL-14435-01
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Cisco Unified Wireless Multicast Design
Introduction
This chapter describes the Cisco Unified Network Multicast in IP multicast forwarding and provides
information on how to deploy multicast in a wireless environment. A prerequisite for using the multicast
performance functionality is that a multicast-enabled network must be configured on all routers between
the controllers and the APs. To accommodate networks that do not support multicast, the controller
continues to support the original unicast packet forwarding mechanism.
information on how to deploy multicast in a wireless environment. A prerequisite for using the multicast
performance functionality is that a multicast-enabled network must be configured on all routers between
the controllers and the APs. To accommodate networks that do not support multicast, the controller
continues to support the original unicast packet forwarding mechanism.
IP multicast is a delivery protocol for information to a group of destinations. It uses the most efficient
strategy to deliver the information over each link of the network. It sends only one copy of the
information at each hop of the network, creating copies only when the links to the destinations split.
Typically, many of today’s networks applications use unicast packets i.e., from one source to one
destination. However when multiple receivers require the same data, replicating the data from the source
to all the receivers as individual unicast packets increases the network load. IP multicast enables efficient
transfer of data from a set of sources to a dynamically formed set of receivers.
strategy to deliver the information over each link of the network. It sends only one copy of the
information at each hop of the network, creating copies only when the links to the destinations split.
Typically, many of today’s networks applications use unicast packets i.e., from one source to one
destination. However when multiple receivers require the same data, replicating the data from the source
to all the receivers as individual unicast packets increases the network load. IP multicast enables efficient
transfer of data from a set of sources to a dynamically formed set of receivers.
IP multicast is typically used today for one way streaming media, such as video to large groups of
receivers. Many cable TV operators, educational institutions and large enterprises have deployed IP
multicast for their content delivery needs. Additionally, there have been some uses of audio and video
conferencing using multicast. Another widespread use of multicast within campus and commercial
networks is for file distribution, particularly to deliver operating system images and updates to remote
hosts. IP multicast has also seen deployment within the financial sector for applications such as stock
tickers and hoot-n-holler systems.
receivers. Many cable TV operators, educational institutions and large enterprises have deployed IP
multicast for their content delivery needs. Additionally, there have been some uses of audio and video
conferencing using multicast. Another widespread use of multicast within campus and commercial
networks is for file distribution, particularly to deliver operating system images and updates to remote
hosts. IP multicast has also seen deployment within the financial sector for applications such as stock
tickers and hoot-n-holler systems.
Overview of Multicast Forwarding in Cisco Unified Wireless
Networks
Networks
With Cisco Unified Wireless Network Software Release 4.1, significant enhancements are made to
support the effective use of multicast in a wireless network. In 3.1 and prior software releases, packets
intended to be multicast were actually unicast on the wireless network. Multicast support was added in
3.2, but there were some configuration limitations that required broadcast to be enabled. With 4.1,
controller software release separate broadcast and multicast support is enabled, allowing networks to be
configured with just multicast, broadcast, or the use of both multicast and broadcast.
support the effective use of multicast in a wireless network. In 3.1 and prior software releases, packets
intended to be multicast were actually unicast on the wireless network. Multicast support was added in
3.2, but there were some configuration limitations that required broadcast to be enabled. With 4.1,
controller software release separate broadcast and multicast support is enabled, allowing networks to be
configured with just multicast, broadcast, or the use of both multicast and broadcast.
With the current Cisco Unified Wireless multicast support, each multicast frame received by the
controller from a VLAN on the first hop router was copied and sent to the multicast group configured
on the controller for the AP that are associated, as shown in
controller from a VLAN on the first hop router was copied and sent to the multicast group configured
on the controller for the AP that are associated, as shown in
. The multicast LWAPP packet
containing the multicast packet uses a WLAN bitmap, which tells the receiving AP which WLAN it must