Cisco Systems OL-8550-09 Controller and Switch Interaction, Internal Ports

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Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
AppendixA Configuring the Catalyst 3750G Integrated Wireless LAN Controller Switch
Understanding the Wireless LAN Controller Switch
Controller and Switch Interaction
The Catalyst 3750G switch and its internal controller are managed separately. You can manage the
switch by using the switch CLI, eXpresso, or CNA. You can manage the controller by using the
controller CLI, the embedded controller GUI, or WCS. To use the GUI or WCS, you must configure the
controller management interface, either through the 3750 CLI, the controller CLI, eXpresso, or Express
Setup. See the Catalyst 3750 Integrated Wireless LAN Controller Switch Getting Started Guide for how
to use eXpresso and express setup. To access the controller CLI, enter the session switch-number
processor 1 privileged EXEC command.
When you power on the wireless LAN controller switch, POST is performed separately by both the
Catalyst 3750 switch and by the wireless controller. Both maintain separate configuration files, which
must be separately saved or cleared.
Note these switch and controller interactions:
•The Catalyst 3750G switch and the controller maintain separate configuration files. They are not
automatically synchronized.
•When the switch resets, this automatically resets the controller. When the controller is reset by the
switch, the controller configuration is not automatically saved.
•Password recovery functions separately on the switch and on the controller.
– You can trigger the password recovery procedure on the switch by pressing the switch Mode
button. (See Chapter49, “Troubleshooting”for information about the switch password recovery
procedure.)
– Password recovery on the controller can be performed by selecting clear config from a hidden
boot-up menu accessible if the user initiates an escape from the controller bootup process. This
requires serial console access to the controller through the second console port.
Internal Ports
The two internal Gigabit Ethernet ports connect the switch and controller hardware. These ports carry
the wireless control and data traffic, as well as the switch and controller management traffic. The links
are automatically configured to allow internal traffic between the switch and the controller. In addition,
an internal VLAN ID is chosen by the Catalyst 3750G switch and communicated to the controller. You
cannot configure the internal VLAN.
In order to operate correctly with the controller, the internal ports (identified as Gigabit Ethernet ports
27 and 28) must have these characteristics:
•IEEE 802.1Q trunk mode
•static Ether Channel ports with Port Aggregation Protocol (PAgP) and Link Aggregation Control
Protocol (LACP) disabled
•generation of Dynamic Trunking Protocol (DTP) frames disabled)
•spanning tree protocol (STP) Port Fast mode enabled
•Cisco Discovery Protocol (CDP) disabled
•UniDirectional Link Detection (UDLD) disabled