The default NMSP echo interval between Cisco MSE and a Wireless LAN Controller is 15 seconds. This interval determines how frequently the MSE sends echo messages to the WLC to maintain the NMSP connection and ensure that the link is active and operational. References := (CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide) Reference: https://www.cisco.com/en/US/docs/wireless/mse/3350/6.0/CAS/configuration/guide
/msecg_ch4_CAS.html