Explanation/Reference:
Explanation: With such an arrangement there is no complex mesh of access points & controllers.
Link: http://www.cisco.com/web/learning/le31/le46/cln/qlm/CCDA/design/understanding-wireless- network-
controller-technology-3/player.html
N+N WLC Redundancy
With N+N redundancy, shown in Figure 5-14. an equal number of controllers hack up each other. For
example, a pair of WLCs on one floor serves as a backup to a second pair on another floor. The top WLC
is primary for API and AP2 and secondary for AP3 and AP4. The bottom WLC is primary for AP3 and AP4
and secondary for API and AP2. There should be enough capacity on
Cisco 640-864 Exam
each controller to manage a failover situation.

N+N+1 WLC Redundancy
With N+N+1 redundancy, shown in Figure 5-15, an equal number of controllers back up each other (as
with N+N), plus a backup WLC is configured as the tertiary WLC for the APs. N+N+1 redundancy functions
the same as N+N redundancy plus a tertiary controller that backs up the secondary controllers. The tertiary
WLC is placed in the data center or network operations center

Exam B