Cisco Cisco Aironet 350 Mini-PCI Wireless LAN Client Adapter Guia Do Desenho
2-2
Enterprise Mobility 4.1 Design Guide
OL-14435-01
Chapter 2 Cisco Unified Wireless Technology and Architecture
LWAPP Overview
Figure 2-1
LWAPP APs Connected to a WLC
The LWAPP protocol comprises of a number of functional components; however, only those that
influence the design and operation of a centralized WLAN network are discussed in this document.
influence the design and operation of a centralized WLAN network are discussed in this document.
The key features of LWAPP are:
•
Split MAC tunnel
•
L2 or L3 based tunnels
•
WLC discovery process.
Split MAC
A key component of the LWAPP protocol is the concept of split MAC, where part of the 802.11 protocol
operation is managed by the LWAPP AP, while the remaining parts are managed by the WLC. A diagram
of the split MAC concept is shown in
operation is managed by the LWAPP AP, while the remaining parts are managed by the WLC. A diagram
of the split MAC concept is shown in
.
A generic 802.11 AP, at the simplest level, is nothing more than an 802.11 MAC-layer radio that bridges
WLAN clients to a wired network based on association to a Basic Service Set Identifier (BSSID). See
WLAN clients to a wired network based on association to a Basic Service Set Identifier (BSSID). See
. The 802.11 standard extends the single AP concept (above) to allow multiple APs to
provide an extended service set (ESS), where multiple APs use the same ESS identifier (ESSID,
commonly referred to as an SSID) to allow a WLAN client to connect to a common network via more
than one AP. See
commonly referred to as an SSID) to allow a WLAN client to connect to a common network via more
than one AP. See
.
The LWAPP split MAC concept takes all of the functions normally performed by individual APs and
distributes them between two functional components: an LWAPP AP and a WLC. The two are linked
across a network by the LWAPP protocol and together provide equivalent radio/bridging services in a
manner that is simpler to deploy and manage than individual APs.
distributes them between two functional components: an LWAPP AP and a WLC. The two are linked
across a network by the LWAPP protocol and together provide equivalent radio/bridging services in a
manner that is simpler to deploy and manage than individual APs.
Note
Although ‘split MAC’ facilitates Layer 2 connectivity between the WLAN clients and the wired
interface of the WLC; this does not mean that the LWAPP tunnel will pass all traffic. The WLC forwards
only IP Ethertype frames, and its default behavior is to not forward broadcast and multicast traffic. This
is important to keep in mind when considering multicast and broadcast requirements in a WLAN
deployment.
interface of the WLC; this does not mean that the LWAPP tunnel will pass all traffic. The WLC forwards
only IP Ethertype frames, and its default behavior is to not forward broadcast and multicast traffic. This
is important to keep in mind when considering multicast and broadcast requirements in a WLAN
deployment.
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LWAPP
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Layer 2 or
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