Cisco Cisco 5508 Wireless Controller Referencia técnica
4
High Availability (SSO) Deployment Guide
D r a f t L a b e l — C i s c o C o n f i d e n t i a l
High Availability in Release 7.3 and 7.4
Both the WiSMs in a HA setup keep track of gateway reachability. Active WLC sends an ICMP ping to the gateway using
the Management IP address as the source, and the Standby WLC sends an ICMP ping to the gateway using the Redundancy
Management IP address. Both the WLCs send an ICMP ping to the gateway at a one-second interval.
the Management IP address as the source, and the Standby WLC sends an ICMP ping to the gateway using the Redundancy
Management IP address. Both the WLCs send an ICMP ping to the gateway at a one-second interval.
To achieve HA between WiSM-2, it can be deployed in a single chassis or can also be deployed between multiple chassis
using VSS as well as by extending Redundancy VLAN between two chassis.
using VSS as well as by extending Redundancy VLAN between two chassis.
This diagram shows HA Connectivity in a single chassis and extending Redundancy VLAN in a multiple chassis VSS setup:
Warning:
The Redundancy VLAN should be a non routable VLAN. In other words, no layer 3 interface should be created for
this VLAN and can be allowed on VSL Link to extend HA setup between multiple chassis in VSS setup. It is important to
make sure this VLAN is dedicated for the HA process and is not part of any Data VLAN, or else it may result in unpredictable
results.
make sure this VLAN is dedicated for the HA process and is not part of any Data VLAN, or else it may result in unpredictable
results.
Note:
The Redundancy VLAN should be created like any normal Data VLAN on IOS® switches. Redundancy VLAN is
configured for redundant port on WiSM-2 blades connected to a backplane. There is no need to configure an IP address
for the Redundancy VLAN as it will receive an auto-generated IP which is discussed later in this document.
for the Redundancy VLAN as it will receive an auto-generated IP which is discussed later in this document.
Note:
On Cisco WiSM2 and Cisco Catalyst 6500 Series Supervisor Engine 2T, if HA is enabled, post switchover, the APs
might disconnect and reassociate with the WiSM2 controller. To prevent this from occurring, before you configure HA, we
recommend that you verify–in the port channel–the details of both the active and standby Cisco WiSM2 controllers, that the
ports are balanced in the same order, and the port channel hash distribution is using fixed algorithm. If they are not in order,
you must change the port channel distribution to be fixed and reset Cisco WiSM2 from the Cisco Catalyst 6500 Series
Supervisor Engine 2T. You can use the command
recommend that you verify–in the port channel–the details of both the active and standby Cisco WiSM2 controllers, that the
ports are balanced in the same order, and the port channel hash distribution is using fixed algorithm. If they are not in order,
you must change the port channel distribution to be fixed and reset Cisco WiSM2 from the Cisco Catalyst 6500 Series
Supervisor Engine 2T. You can use the command
show etherchannel port-channel
to verify the port channel member
order and load value. You can use the
config command port-channel hash-distribution fixed
to make the distribution
fixed.
Note:
To support the active and standby WLCs in different data centers, in release 7.5, back-to-back redundancy port
connectivity between peers is no longer mandatory and the redundancy ports can be connected via switches such that
there is L2 adjacency between the two controllers. See
there is L2 adjacency between the two controllers. See
for more information.
Introduction of New Interfaces for HA Interaction
Redundancy Management Interface
The IP address on this interface should be configured in the same subnet as the management interface. This interface will check
the health of the Active WLC via network infrastructure once the Active WLC does not respond to Keepalive messages on the
Redundant Port. This provides an additional health check of the network and Active WLC, and confirms if switchover should or
should not be executed. Also, the Standby WLC uses this interface in order to source ICMP ping packets to check gateway
reachability. This interface is also used in order to send notifications from the Active WLC to the Standby WLC in the event of
Box failure or Manual Reset. The Standby WLC will use this interface in order to communicate to Syslog, the NTP server, and
the TFTP server for any configuration upload.
the health of the Active WLC via network infrastructure once the Active WLC does not respond to Keepalive messages on the
Redundant Port. This provides an additional health check of the network and Active WLC, and confirms if switchover should or
should not be executed. Also, the Standby WLC uses this interface in order to source ICMP ping packets to check gateway
reachability. This interface is also used in order to send notifications from the Active WLC to the Standby WLC in the event of
Box failure or Manual Reset. The Standby WLC will use this interface in order to communicate to Syslog, the NTP server, and
the TFTP server for any configuration upload.