1. Technical Field
The present invention relates to a communication method and a communication system that achieve a seamless connection between apparatuses.
2. Related Art
With the development of communication networks in recent years, network address translation (NAT) has been commonly used in view of securing a certain number of IP addresses and ensuring security. Routers and servers equipped with NAT functions relay communications while translating private addresses into global addresses and vice versa.
Also, in some cases, mobile terminals frequently move to different address spaces, and address translation frequently occurs due to the movement. Specifically, in view of increasing the communication speed of mobile terminals, reducing loads in mobile carrier communication, and so on, more and more mobile terminals are now using both mobile carrier communication and Wi-Fi communication. A mobile terminal connects to a Wi-Fi base station when within an area capable of Wi-Fi communication, and connects to a base station for mobile carrier communication when within an area other than Wi-Fi areas. A mobile terminal also switches its connection from a Wi-Fi base station to a different Wi-Fi base station in some cases.
Meanwhile, there have been systems that use both TCP and UDP (see Japanese Patent Application Publication No. 2014-49905, for example) in order to ensure reliable data communication and prevent data delay. In this system described in Japanese Patent Application Publication No. 2014-49905, relay software captures TCP packets from an application, converts the TCP packets into UDP packets, and transfers the data of the UDP packets.