Next Generation Networks (NGNs) are primarily propelled by huge potential market for systems of communication and services to suit individuals, which yield ubiquitous and tether-less access to users. Providing seamless handover and ubiquitous services in NGN presents many new research challenges. Priority based call management scheme is necessary to provide low call dropping probability for high priority services by means of channel reservation separately for new call and handoff call. Most of the existing call admission control (CAC) schemes do not consider the vertical handoff from WLAN to Cellular and surprisingly users do not access WLAN even when WLAN facility is available. Proposed call management scheme, which considers all possible vertical handoff scenarios and provides the maximum usage of WLAN. As result, any blocked request in WLAN is taken back by the overlaying Cellular system, if channels are available. So, a request is dropped/blocked only when all the channels of both Cellular and WLAN systems are busy. Main effort is essential to design a Call management scheme for the interworking of Cellular/WLAN, in which service type of the user has been considered. The analytical model has been derived for the call management scheme and validates the same with necessary OPNET simulation results. We provide an extensive numerical result to show that proposed scheme performs better than the existing complementary WLAN (C-WLAN) scheme. © 2006-2017 Asian Research Publishing Network (ARPN). All rights reserved.