Wireless/Redundant Edge Services xl Module Management and Configuration Guide WS.01.03 or greater

4-10
Redundancy Groups
High Availability for Wireless Services
Adopting RPs
In a typical configuration with the primary module in active mode and the
redundant module in standby mode, the primary module adopts all the RPs it
can detect—until it reaches its maximum number of RP licenses. In standby
mode, the redundant module adopts RPs only in certain circumstances:
■ The redundant module does not receive a heartbeat from the primary
module for the length of time specified in the hold period option.
■ The primary module fails to adopt an RP, although it has enough RP
licenses to adopt the RP.
Table 4-1 describes some of these situations.
Table 4-1. Situations in Which the Redundant Module (in Standby Mode)
Adopts RPs
If the primary module is unavailable and the redundant module adopts all the
RPs, the redundant module continues to support these RPs even after the
primary module becomes available again. This minimizes the danger of two
modules attempting to adopt the same RP.
RP Licensing for Redundancy Groups
Because only the primary module has RP licenses, the total number of licenses
installed on this module is the maximum number of licenses available to the
entire redundancy group. If the primary module becomes unavailable, the
redundant module is authorized to adopt the maximum number of RPs for the
redundancy group. (For information about licenses, see “Radio Port Licenses”
on page 2-76.)
Situation Possible Causes
The redundant module misses
heartbeats from the primary
module.
• The primary module has failed.
• The wireless services-enabled switch in which the
primary module is installed has failed.
• A failed network connection has isolated the wireless
services-enabled switch from the network.
The primary module fails to adopt
an RP.
• The primary module’s internal downlink port has not
been tagged for the RP VLAN.
• The primary module is explicitly prohibited from
adopting the RP.