Most of the existing security mechanisms available in literature add complexity and overhead to handover management. Hence it is very important to maintain trade-off between security and QoS during handover. The tradeoff among these two parameters will increase more when service provider is different from network provider. In such cases, it is essential for a roaming user to get authenticated both from network provider as well as service provider. Here, AAA protocol is used for authentication, which is more costly. Furthermore the distance from the home network and visited network is higher which adds handover delay (Faraz et al., 2007). MPA (Media-Independent Pre-Authentication) (dutta et al., 2008) is another effective authentication methodology used in handover. MPA mechanism does not provide security while exchanging messages during handover and more packets are lost if handover takes place before the completion of binding update. But it also adds latency during the handover process. The Extensible Authentication Protocol (EAP) is a client server protocol which uses the authentication server to implement authentication process (Gaabab et al., 2007). (Reem et al. 2014) have utilized EAP Authentication and Key Agreement (EAP-AKA) for IMS based WiMAX/LTE secure handover. But EAP-AKA process involves various exchange of messages and repeated execution every time when a handover occurs. IPSec is one of the techniques used for data security, for providing security to those messages that run over IP protocols, i.e., IPv6.For real-time services, such as voice and video, the SIP (Rosenberg et al., 2002) is becoming the leading signaling protocol in IP networks and has already been accepted as the signaling standard by IETF and 3GPP. SIP is used as the signaling protocol for IMS networks. Furthermore SIP has the provision for encapsulating the IP Sec packets within the SIP request and Response message structure.