In order to help ISPs to deploy a mobile IP network into current internet environment with satisfying users? mobility requirements, this paper evaluates and compares the performance of MIPv4 and MIPv6 networks. This paper shows that TCP performance in MIPv6 network outperforms that of MIPv4 network in terms of amount of dropped packets and lasting the connection with mobile node and corresponding node. And so, in this paper, we design a simple deployment approach which all mobile node operates in MIPv6 networks under fixed IPv4 network environments.