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You can bundle all eight
ports on a Cisco 5508 Controller into a single link.
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Terminating on two different
modules within a single Catalyst 6500 series switch provides redundancy and
ensures that connectivity between the switch and the controller is maintained
when one module fails. The controller’s port 1 is connected to Gigabit
interface 3/1, and the controller’s port 2 is connected to Gigabit interface
2/1 on the Catalyst 6500 series switch. Both switch ports are assigned to the
same channel group.
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LAG requires the EtherChannel
to be configured for 'mode on' on both the controller and the Catalyst switch.
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Once the EtherChannel is
configured as on at both ends of the link, the Catalyst switch should not be
configured for either Link Aggregation Control Protocol (LACP) or Cisco
proprietary Port Aggregation Protocol (PAgP) but be set unconditionally to LAG.
Because no channel negotiation is done between the controller and the switch,
the controller does not answer to negotiation frames and the LAG is not formed
if a dynamic form of LAG is set on the switch. Additionally, LACP and PAgP are
not supported on the controller.
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If the recommended
load-balancing method cannot be configured on the Catalyst switch, then
configure the LAG connection as a single member link or disable LAG on the
controller.
Figure 3. Link Aggregation with the
Catalyst 6500 Series Neighbor Switch
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You cannot configure the
controller’s ports into separate LAG groups. Only one LAG group is supported
per controller. Therefore, you can connect a controller in LAG mode to only one
neighbor device.
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When you enable LAG or make
any changes to the LAG configuration, you must immediately reboot the
controller.
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When you enable LAG, you can
configure only one AP-manager interface because only one logical port is
needed. LAG removes the requirement for supporting multiple AP-manager
interfaces.
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When you enable LAG, all
dynamic AP-manager interfaces and untagged interfaces are deleted, and all
WLANs are disabled and mapped to the management interface. Also, the
management, static AP-manager, and VLAN-tagged dynamic interfaces are moved to
the LAG port.
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Multiple untagged interfaces
to the same port are not allowed.
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When you enable LAG, you
cannot create interfaces with a primary port other than 29.
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When you enable LAG, all
ports participate in LAG by default. You must configure LAG for all of the
connected ports in the neighbor switch.
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When you enable LAG, if any
single link goes down, traffic migrates to the other links.
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When you enable LAG, only one
functional physical port is needed for the controller to pass client traffic.
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When you enable LAG, access
points remain connected to the controller until you reboot the controller,
which is needed to activate the LAG mode change, and data service for users
continues uninterrupted.
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When you enable LAG, you
eliminate the need to configure primary and secondary ports for each interface.
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When you enable LAG, the
controller sends packets out on the same port on which it received them. If a
CAPWAP packet from an access point enters the controller on physical port 1,
the controller removes the CAPWAP wrapper, processes the packet, and forwards
it to the network on physical port 1. This may not be the case if you disable
LAG.
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When you disable LAG, the
management, static AP-manager, and dynamic interfaces are moved to port 1.
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When you disable LAG, you
must configure primary and secondary ports for all interfaces.
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When you disable LAG, you
must assign an AP-manager interface to each port on the controller. Otherwise,
access points are unable to join.
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Cisco 5500 Series Controllers
support a single static link aggregation bundle.
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LAG is typically configured
using the Startup Wizard, but you can enable or disable it at any time through
either the GUI or CLI.
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When you enable
LAG on Cisco 2500 Series Controller to which the direct-connect access point is
associated, the direct connect access point is disconnected since LAG enabling
is still in the transition state. You must reboot the controller immediately
after enabling LAG.
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In 8500 when more than 1000 APs joining WLC flapping occurs, to
avoid this do not add more than 1000 Aps on a single catalyst switch for Capwap
IPv6.