Информационное Руководство для Cisco Cisco 2000 Series Wireless LAN Controller
the Cisco Wireless LAN Controller Configuration Guide, Release 6.0.
Q. Can I configure a LAG connection that spans across multiple
switches?
switches?
A. Yes. LAG with VSS, or a stacked switch (3750/2960) setup, will work as long as the
fragments of an IP packet are sent to the same port. The idea is that if you go to multiple
switches, the ports must belong to the same L2 entity with regards to load balancing
decisions.
fragments of an IP packet are sent to the same port. The idea is that if you go to multiple
switches, the ports must belong to the same L2 entity with regards to load balancing
decisions.
Q. How does a WLC switch packets?
A. All the client (802.11) packets are encapsulated in a LWAPP packet by the LAP and sent
to the WLC. WLC descapsulates the LWAPP packet and acts based on the destination IP
address in the 802.11 packet. If the destination is one of the wireless clients associated to the
WLC, it encapsulates the packet again with the LWAPP and sends it to the LAP of the client,
where it is decapsulated and sent to the wireless client. If the destination is on the wired side
of the network, it removes the 802.11 header, adds the Ethernet header, and forwards the
packet to the connected switch, from where it is sent to the wired client. When a packet
comes from the wired side, WLC removes the Ethernet header, adds the 802.11 header,
encapsulates it with LWAPP, and sends it to the LAP, where it is decapsulated, and the
802.11 packet is delivered to the wireless client. For more information about this, refer to the
LWAPP Fundamentals section of the document Deploying Cisco 440X Series Wireless LAN
Controllers.
to the WLC. WLC descapsulates the LWAPP packet and acts based on the destination IP
address in the 802.11 packet. If the destination is one of the wireless clients associated to the
WLC, it encapsulates the packet again with the LWAPP and sends it to the LAP of the client,
where it is decapsulated and sent to the wireless client. If the destination is on the wired side
of the network, it removes the 802.11 header, adds the Ethernet header, and forwards the
packet to the connected switch, from where it is sent to the wired client. When a packet
comes from the wired side, WLC removes the Ethernet header, adds the 802.11 header,
encapsulates it with LWAPP, and sends it to the LAP, where it is decapsulated, and the
802.11 packet is delivered to the wireless client. For more information about this, refer to the
LWAPP Fundamentals section of the document Deploying Cisco 440X Series Wireless LAN
Controllers.
Q. When should I use the master controller mode on a WLC?
A. When there is a master controller enabled, all newly added access points with no primary,
secondary, or tertiary controllers assigned associate with the master controller on the same
subnet. This allows the operator to verify the access point configuration and assign primary,
secondary, and tertiary controllers to the access point using the All APs > Details page.
secondary, or tertiary controllers assigned associate with the master controller on the same
subnet. This allows the operator to verify the access point configuration and assign primary,
secondary, and tertiary controllers to the access point using the All APs > Details page.
The master controller is normally used only when adding new access points to the Cisco
Wireless LAN solution. When no more access points are being added to the network, Cisco
WLAN solution recommends that you disable the master controller.
Wireless LAN solution. When no more access points are being added to the network, Cisco
WLAN solution recommends that you disable the master controller.
Q. Does the 4400 WLC route packets between VLANs?
A. The 4400 WLC is an appliance that attaches to your network but does not function like a
router. There must be a Layer 3 device to route packets between VLANs. The WLC maps the
SSID of the clients to the VLAN subnet and puts them back out on the management interface
for the upstream routers to route packets.
router. There must be a Layer 3 device to route packets between VLANs. The WLC maps the
SSID of the clients to the VLAN subnet and puts them back out on the management interface
for the upstream routers to route packets.
Q. How do I configure WLAN on a WLC?
A. WLAN is similar to that of SSID in the access points. It is required for a client to associate
with its wireless network. In order to configure a WLAN on a WLC, refer to the sample
configuration in the document Guest WLAN and Internal WLAN using WLCs Configuration
Example.
with its wireless network. In order to configure a WLAN on a WLC, refer to the sample
configuration in the document Guest WLAN and Internal WLAN using WLCs Configuration
Example.